Abstracts ISHHC 2009 Synthesis, Characterization and Catalytic Evaluation of...

ISHHC XIV 13-18 September 2009

International Symposium on Relations between

Homogeneous and Heterogeneous Catalysis

Foto: KJ Szabó

Abstracts

Jan‐Erling Bäckvall, Ed. Stockholm University, Sweden

SPONSORS We would like to thank our sponsors for their invaluable financial support for ISHHC XIV

Granholms stiftelse

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Scientific program

Plenary lecture (PL), Keynote lecture (KL), Oral contribution (OC)

Sunday, September 13, 2009

15.00-19.00 Registration in Aula Magna

18.00 Get together

Monday, September 14, 2009

Lecture Hall Aula Magna (Left)

09.00 Opening remarks

Chair person: John Meurig Thomas

09.15 PL1 Gabor Somorjai, University of California, Berkeley, USA Selective Nanocatalysis of Organic Transformation by Metals. Concepts, Instruments and Model Systems

10.00 PL2 Karl Petter Lillerud, University of Oslo, Norway MOFs Tuning Heterogeneous Catalysts towards Enzyme Functionality

10.45 Coffee

Chair person: Christina Moberg

11.15 PL3 Robert Grubbs, California Institute of Technology, USA Olefin Metathesis Catalysts for the Synthesis of Molecules and Materials

12.00 PL4 Takao Ikariya, Tokyo Institute of Technology, Japan Recent Progress in Concerto Molecular Catalysis

12.45 Lunch

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Lecture Hall Aula Magna (Right)

Chair person: Björn Åkermark Chair person: Oscar Pàmies

14.30 OC1 Hiroaki Sasai, Exploring a New Paradigm in Immobilization of Multicomponent Asymmetric Catalyst

OC8 Christina Moberg, Minor Enantiomer Recycling

14.50 OC2 Dehua He, Hydroformylation of Olefins over Immobilized Rh-P Complex Catalysts

OC9 Martin Albrecht Mode of Action of Normal and Abnormal Carbene Metal Complexes in Hydrogenation Catalysis

15.10 OC3 Masaya Sawamura, Directed ortho-Borylation of Functionalized Arenes Catalyzed by a Silica–Supported Compact Phosphine–Iridium System

OC10 Thoru Yamada, Enantioselective CO2 Incorporation to Propargylic Alcohols Catalyzed by Silver Complexes

15.30 Coffee Coffee

Chair person: Sven Oscarsson Chair person: Hans Adolfsson

16.00 OC4 Valentin P. Ananikov, Catalyst Leaching - an Efficient Tool for Constructing New Catalytic Reactions: Pd and Ni Chalcogenides in Selective Carbon-Heteroatom Bond Formation

OC11 Axel Jacobi von Wangelin, On Direct Iron-Catalyzed Cross-Coupling Reactions

16.20 OC5 Carmen Claver, Catalytic activity of Metal Nanoparticles stabilized with Chiral Modular Ligands

OC12 Katrin Baer, Synthesis of chiral 1,3-diols with two stereogenic centres by using organo- and biocatalysis

16.40 OC6 Juliane Keilitz, Homogenization of Heterogeneous Catalysts: Stabilization of Metal-Nanoparticles by Soluble Dendritic Architectures and Applications thereof

OC13 Kai Szeto, Selective methane coupling to ethane and hydrogen catalyzed by grafted Tantalum or Tungsten hydride

17.00 OC7 Elin Larsson, Plasmonics meets Catalysis: A Novel Highly Versatile Remote Sensing Technique to Monitor Catalytic Reactions

OC14 Ken-ichi Shimitzu, Direct Dehydrogenative Amide Synthesis from Alcohols and Amines Catalyzed by γ-Alumina Supported Silver Cluster

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Tuesday, September 15, 2009


09.00 Introduction to IDECAT day (Gabriele Centi)

Chair person: Gabriele Centi

09.10 PL5 Manfred Reetz, Max-Planck-Institut, Mülheim, Germany Directed Evolution of Enantioselective Enzymes as Catalysts in Organic Chemistry

09.55 PL6 Claudio Bianchini, ICCOM-CNR, Florence, Italy Molecular and nanosized catalysts for the conversion of renewables into energy & chemicals

10.40 Coffee

Chair person: Kálmán Szabó

11.05 PL7 Rutger van Santen, Eindhoven University of Technology, The Netherlands, Molecular Recognition in Heterogeneous Catalysis

11.50 KL1 Alessandra Quadrelli, University of Lyon, France, Dinitrogen Dissociation on an Isolated Surface Tantalum Atom

12.25 KL2 David Cole-Hamilton, St. Andrews University, Scotland Biphasic and flow systems involving water or supercritical fluids

13.00 Lunch

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Chair person: Carmen Claver

14.30 KL3 Dirk De Vos, Katholieke Universiteit Leuven, Belgium Dynamic Kinetic Resolution with heterogeneous and biocatalysts: Concepts and applications to fine chemicals synthesis

15.05 KL4 Matthias Beller, University of Rostock, Germany, Development of Catalysts for Hydrogen Generation

15.40 Coffee

Chair person: Lynne McCusker Chair person: Pierluigi Barbaro

16.10 OC15 Hendrikus C. L. Abbenhuis, Hybrid Catalysis with Nanostructured POSS Metal derivatives

OC19 Juan Cámpora, Group 10 PCP Pincer Complexes as Models for Catalytic Alcohol Carboxylation

16.30 OC16 Elena Groppo, Sub-nanometric Pd particles stabilized inside highly cross-linked polymeric matrices

OC20 Christine Czauderna, Development of Chiral Wide Bite-Angle Diphosphine Ligands

16.50 OC17 Chloé Thieuleux, Selective localisation of Pt nanoparticles in the pores or/and walls of a mesostructured silica matrix via the control of hydrophobic/hydrophilic interactions

OC21 Marina Gruit, Gold and platinum-catalyzed intramolecular cyclization of alkynes: Synthesis of pyrrolo-azepinone derivatives

17.10 OC18 Robertus J.M. Klein Gebbink, Extraordinary catalytic performance of dendritic triphenyl-phosphines (Dendriphos) in Suzuki-Miyaura cross-coupling

OC22 José M. Fraile, The modulation of diastereo- and enantioselectivity by immobilization of chiral catalysts

17.30-19.00 Poster session 1 and refreshments

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Wednesday, September 16, 2009


Chair person: Belén Martín-Matute

09.00 PL8 David Milstein, Weizmann Institute of Science, Israel, Design of New Catalysis Based on Cooperative Pincer-Ligand Systems

09.45 PL9 Antonio Echavarren, ICIQ, Tarragona, Spain, New Rearrangements for the Building of Molecular Complexity via Gold Catalysis

10.30 Coffee

Chair person: Per-Ola Norrby

10.50 PL10 Odile Eisenstein, University of Montpellier, France Using DFT Calculations for optimizing a catalyst

11.35 KL5 Xinhe Bao, Dalian Institute of Chemical Physics, China, Unique Catalytic Chemistry of the Nano-confined Systems

12.10 KL6 Christina White, University of Illinois at Urbana Champaigne, USA

12.45 Poster session 2

Ca 13.40 Lunch

14.45 Boat trip in the Stockholm archipelago

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Thursday, September 17, 2009


Chair person: Dirk De Vos

09.00 PL11 Benoit Pugin, Solvias AG, Basel, Switzerland, Immobilized Catalysts for Enantioselective Hydrogenation: When will they be used ?

09.45 PL12 Nicholas Turner, University of Manchester, United Kingdom, Directed Evolution of Enzymes: New Biocatalysts for Organic Synthesis

10.30 Coffee

Chair person: Alessandra Quadrelli

11.00 KL7 Noritaka Mizuno, University of Tokyo, Japan, Green Oxidation Reactions by Polyoxometalate-Based Catalysts: From Molecular to Solid Catalysts

11.35 KL8 Christopher Jones, Georgia Institute of Technology, USA, Heterogenized M-Salen Catalysts for Enantioselective Reactions: Catalyst Design, Structure-Reactivity Trends, and Deactivation Pathways

12.10 KL9 Miquel Salmeron, Lawrence Berkeley National Laboratory, USA, In-situ microscopy and spectroscopy for structural and catalytic studies

12.45 Lunch

14.00 Poster session 3

15.30 Coffee

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Lecture Hall Aula Magna (Right)

Chair person: Lucien Saussine Chair person: Timo Privalov

15.50 OC23 Montserrat Gómez, Palladium nanoparticles in ionic liquids: homogeneous versus heterogeneous catalytic behaviour

OC28 Licheng Sun, Visible light driven water oxidation catalyzed by molecular Ru complexes in homogeneous systems

16.10 OC24 Marco Haumann, Supported Ionic Liquid Phase (SILP) Catalysts – Advanced Materials for Process Intensification and Improved Screening in Homogeneous Catalysis

OC29 Mei Wang, Photoinduced H2-production with Fe- and Co-based molecular catalysts

16.30 OC25 Peter Steffen Schulz, NMR-Spectroscopy as a tool for Investigation of Ionic Liqiuds properties

OC30 Vincent Artero, Cobaloxime-Catalyzed Hydrogen Electro- and Photo-Production

16.50 OC26 Peter Wasserscheid, The SILP catalysis concept – molecular catalysis in heterogeneous systems

OC31 Sven Rau, Modelled after nature - photocatalytic water splitting with redoxactive metal complexes

17.10 OC27 Igor Ignatyev, Cellulose Hydrogenolysis in Ionic Liquids

OC32 Björn Åkermark, Towards Catalytic Water Oxidation: Model Systems for PS II

19.30 Banquet at the Vasa museum

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Friday, September 18, 2009


Chair person: Xiaodong Zou

09.30 PL13 John Meurig Thomas, University of Cambridge, United Kingdom, Single-site Nanoporous Solids Which Unite the Advantages of Heterogeneous and Homogeneous Catalysis

10.15 KL10 Wenbin Lin, University of North Carolina, USA, Chiral Metal-Organic Frameworks for Asymmetric Catalysis

10.50 Coffee

Chair person: Alexey Tsyganenko

Chair person: Mats Johnsson

11.10 OC33 Aleix Comas-Vives, Nucleophilic Addition Step of the Wacker Process: Mechanistic Answers from Molecular Dynamics in Water

OC36 Regis Gauvin, Well-defined silica-grafted calcium reagents: hybrid materials for supported catalysis

11.30 OC34 Yurii V. Geletii, An All-Inorganic, Highly Active Tetraruthenium Homogeneous Catalyst for Water Oxidation. Reaction Mechanism

OC37 Emmanuelle Göthelid, Biomimetic Oxidation Catalyst Immobilised on Silicon Wafers and Silicon Particles

11.50 OC35 Philippe Kalck, High Pressure Infrared and NMR Studies of Catalytic Systems in Carbonylation Reactions

OC38 Gary Attard, Studies of Enantioselectivity at Well Defined Supported Heterogeneous Catalysts

12.10 Poster award and Closing

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Plenary lectures

PL1-PL13

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Selective Nanocatalysis of Organic Transformation by Metals Concepts, Instruments and Model Systems

Gabor A. Somorjai

Department of Chemistry and Lawrence Berkeley National Laboratory, University of California, Berkeley

Monodispersed transition metal (Pt, Rh, Pd) nanoparticles (NP) in the 0.8-10 nm range have been synthesized and are being used to probe catalytic selectivity in multipath organic transformation reactions. The turnover rates and product distributions depend on their size, shape, oxidation states, and their composition in case of bimetallic NP systems. Less than 2 nm dendrimer-supported platinum and rhodium NPs usually have higher oxidation states and can be utilized for catalytic cyclization and hydroformylation reactions that previously were produced only by homogeneous catalysis. Transition metal nanoparticles in metal core (Pt, Co)–inorganic shell (SiO2) structure exhibit exceptional thermal stability and are well-suited to perform catalytic reactions at high temperatures (> 400 ºC). Instruments developed in our laboratory permit the atomic and molecular level study of NPs under reaction conditions (SFG, ambient pressure XPS and high pressure STM). These studies indicate continuous restructuring of the metal substrate and the adsorbate molecules, changes of oxidation states with NP size and surface composition variations of bimetallic NPs with changes of reactant molecules. The facile rearrangement of NP catalysts required for catalytic turnover makes nanoparticle systems (heterogeneous, homogeneous and enzyme) excellent catalysts.

PL-1

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MOFs Tuning Heterogeneous Catalysts towards Enzyme Functionality

Karl Petter Lillerud, Mats Tilset and Unni Olsbye

inGAP/Kjemisk Institutt, Universitetet i Osl,o PB 10033Blindern, Norway

Everyone that works within the field of catalysis is looking towards the amazing functionality of nature’s catalysts, the enzymes. It is particularly the mild conditions that these catalysts are able to operate at and the selectivity that they demonstrate that make these materials dream targets for scientists involved in the art of synthesizing homogeneous and heterogeneous industrial catalysts. But enzymes have also a week points, their low thermal stability and their often too slow reaction rates for an economical industrial process has to be overcome. The obvious solution would be the copy the catalytic active centre into a robust open framework. A key property to an enzyme is the selectivity, this property is partly regulated by steric constraints surrounding the catalytically active cite. The microporous zeolite based catalysts show in some cases impressive selectivity based on the geometrical constraints imposed by the size and shape of the regular channels in these crystalline silicate phosphate based structures and enzyme like properties has been claimed but the pure inorganic nature of the selective internal surface in these materials make it impossible to mimic many important enzymatic properties. The new generation of microporous materials, Metal Organic Frameworks are hybrid organic inorganic structures. This dualistic nature offers an unprecedented flexibility in the possibility to incorporate both organic and metallic functional groups into the ordered crystalline lattice and thereby opening up for a much grater possibility to copy structural motives known from enzymes into much simpler but also more stable open structures. Several groups are working on development of new catalyst by this approach. We will illustrate these approaches with structures that mimic anhydrase and C-H activation.

Zr-MOF-UiO-67_bipyridine with tetrahedral cobalt in a position that might mimic the active site in the enzyme carbonic anhydrase. MOF structure left active site in anhydrase right.

PL-2

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Olefin Metathesis Catalysts for the Synthesis of Molecules and Materials

Robert H. Grubbs

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125 email: [email protected]

Ruthenium based olefin metathesis catalysts have provided new routes to olefins that appear in a variety of structures. Their functional group tolerance and ease of use allow their application in the synthesis of multifunctional bioactive molecules. The same systems are also useful for the synthesis of an array of new materials from multifunctional polymers to supramolecular systems. Underlying these developments has been the discovery of active catalysts with controlled selectivity through the synthesis of new ligands that control the geometry of the intermediate carbene and metallacycle complexes.

References "Cyclic Ruthenium-Alkylidene Catalysts for Ring-Expansion Metathesis Polymerization." A. J. Boydston, J. A.

Kornfield, I. A. Gorodetskaya, R. H. Grubbs "Well-Defined Silica-Supported Olefin Metathesis Catalysts" D. P. Allen, M. M. Van Wingerden, R. H. Grubbs

Org. Let. 2009, 1261-1264 "Pulsed-Addition Ring-Opening Metathesis Polymerization: Catalyst-Economical Syntheses of Homopolymers

and Block Copolymers" J. B. Matson, S. C. Virgil, R. H. Grubbs , J. Am. Chem. Soc. 2009, 131, 3355-3362 "Ring-Expansion Metathesis Polymerization: Catalyst-Dependent Polymerization Profiles" Y. Xia, A. J.

Boydston, Y. F. Yao, J. A. Kornfield , I. A. Gordodetskaya, H. W. Spiess, R. H. Grubbs J. Am. Chem. Soc. 2009, 131, 2670-2677.

"A Direct Route to Cyclic Organic Nanostructures via Ring-Expansion Metathesis Polymerization of a Dendronized Macromonomer" Boydston AJ, Holcombe TW, Unruh DA, J. M. Frechet, R. H. Grubbs J. Am. Chem. Soc. 2009, 131, 5388

"Effects of NHC-Backbone Substitution on Efficiency in Ruthenium-Based Olefin Metathesis" K. M. Kuhn, J-B. Bourg, C. Chung, S. C. Virgil, R. H. Grubbs J. Am. Chem. Soc. 2009, 131, 5313-5320

"Conformations of N-Heterocyclic Carbene Ligands in Ruthenium Complexes Relevant to Olefin Metathesis" I. C. Stewart, D. Benitez, D. J. O'Leary, E. Tkatchouk, M. W. Day, W. A. Goddard, R. H. Grubbs J. Am. Chem. Soc. 2009, 131, 1931-1938

PL-3

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mailto:[email protected]

Recent Progress in Concerto Molecular Catalysis

Takao Ikariya

Tokyo Institute of Technology, Japan

Recent advance in the conceptually new chiral bifunctional transition metal based catalysts promoted asymmetric reactions, the concerto molecular catalysis, is described. This bifunctional molecular catalyst originated from a metal/NH acid-base synergy effect offered a great opportunity to open up fundamental aspects for stereoselective transformation including enantioselective C–H, C–C, C–N bond formation and is now realized to be a powerful tool to access chiral compounds in organic synthesis. I will focus on the reductive and oxidative transformation including aerobic oxidation alcohols developed with the bifunctional mono- and di-nuclear metal catalysts

PL-4

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Directed Evolution of Enantioselective Enzymes as Catalysts in Organic Chemistry

Manfred T. Reetz

Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim/Ruhr, Germany E-mail: [email protected]

Some time ago we proposed and implemented experimentally a new approach to asymmetric catalysis, namely the directed evolution of enantioselective enzymes as catalysts in synthetic organic chemistry and in biotechnology. It is based on repeating cycles of gene mutagenesis, expression and high-throughput screening for enantioselectivity. The most often used mutagenesis methods in the emerging field of directed evolution are error-prone PCR (epPCR), saturation mutagenesis and DNA shuffling, methods that we used in our original proof-of-principle study using a lipase back in 1996-1997. Subsequently we applied our approach to other enzymes, and a number of industrial and academic groups have likewise contributed to this new area of asymmetric catalysis. However, as in modern synthetic organic chemistry, methodology development is crucial for further progress. The challenge is to devise Darwinian methods and strategies for probing protein space more efficiently than in the past, enabling fast directed evolution. To this end we have developed Iterative Saturation Mutagenesis (ISM) in its two embodiments: CASTing for controlling enantioselectivity and B-FIT for improving the thermostability of enzymes. In order to assess the efficacy of these methodological developments, we have devised a deconvolution strategy which allows the construction of fitness landscapes. Applications in enantioselective transformations using lipases, epoxide hydrolases, reductases and monooxygenases such as Baeyer-Villigerases will be highlighted in the talk.

PL-5

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Molecular and nanosized catalysts for the conversion of renewables into energy & chemicals

Claudio Bianchini

Istituto di Chimica dei Composti Organometallici (ICCOM-CNR) Via Madonna del Piano 10, 50019 Sesto Fiorentino (FI), Italy

[email protected], www.iccom.cnr.it

Many relevant renewable resources from agriculture such as alcohols and sugars are appropriate anolytes for both direct fuel cells (DFCs) and electrolyzers for H2 production. The oxidation of the fuel in a DFC can be controlled by the anode electrocatalyst that can be appropriately designed to convert the fuel into energy and higher added value products. Likewise, the production of H2 in an electrolyzer can be achieved at much lower overpotentials by replacing water with a suitable anolyte that can be selectively converted into a chemical product.

In this lecture are described molecular and nanosized metal catalysts for the conversion of renewables into energy & chemicals and their application in effective DFCs and electrolyzers. Two examples of the concept forwarded in this lecture are illustrated in Scheme 1.

CH3CH2OH/H2O CH3COOH + energy

CH3CH2OH/H2OElectrolyzer

CH3COOH

DFC

+ H2

Scheme 1

References 1) Bambagioni, V.; Bianchini, C.; Filippi, J.; Oberhauser, W.; Marchionni, A.; Vizza, F.; Psaro, R.;

Sordelli, L.; Foresti, M. L.; Innocenti, M. ChemSusChem, 2009, 2, 99. 2) Bambagioni, V.; Bianchini, C.; Filippi, J.; Oberhauser, W.; Marchionni, A.; Vizza, F.; Teddy, J.; Serp,

P.; Zhiani, M. J. Power Sources 2009, . 3) Bianchini, C.; Bambagioni,, V.; Filippi, J.; Marchionni, A.; Vizza, F.; Bert, P.; Tampucci, A.

Electrochem. Commun. 2009, 4) Bert, P., Bianchini C.; Catanorchi, S.; Filpi, A.; Nugent, D.; Ragnoli, M.; Tampucci A., Vizza, F.; Ren,

X. PCT/EP2007/062555, WO/2008/061975. 5) Bert, P., Bianchini C.; Giambastiani G.; Marchionni, A.; Tampucci A., Vizza, F. PCT/EP2008/055706. 6) Bianchini, C.; Shen, P. K. Chem. Rev. 2009 7) Cui, G.; Song, S.; Shen, P. K.; Kowal, A.; Bianchini, C. J. Phys. Chem. 2009.

PL-6

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http://www.iccom.cnr.it/

Molecular Recognition in Heterogeneous Catalysis

Rutger A. van Santen

Schuit Institute of Catalysis, Laboratory of Inorganic Chemistry and Catalysis, Eindhoven University of Technology, The Netherlands

A classical issue in heterogeneous catalysis is the dependence of selectivity or activity on catalyst particle size. For stereochemically controlled reactions the influence of shape and connectivity of nanoporous materials on catalytic selectivity and activity is still not well understood.

We will address these issues using as guiding principle the concept of molecular recognition, as proposed in molecular enzyme catalysis. We ask ourselves the question whether there is an analogue to molecular recognition in heterogeneous catalysis. Such a question has become useful due to advances in computational catalysis. Computational techniques now provide transition state energies and structures of elementary chemical reaction steps on reactive surfaces.

Using such detailed information we will give an interpretation of the three different classes of structure sensitivity that are observed for reactions catalyzed by transition metal particles. It will appear that reactions that show a strong increase in rate with decreasing particle size and reactions that behave independently of particle size, are complementary. They relate to reactions in which σ bonds are activated. The other class of reactions that show a maximum in rate as a function of particle size relate to reactions in which π bonds are activated.

Bulk chemical reactions that take place in hydrogen storage systems can also show strong particle size dependence. Now a significant parameter is the difference of surface and bulk energies. A comparison of NaH and AlH3 shows that particle size dependent hydrogen desorption behaves very different. This difference in behavior relates to the difference in chemical bonding in these systems. Whereas bonding in NaH is predominantly ionic, covalent and hydrogen bonding is typical for AlH3.

Zeolites are prototype systems for reactivity analysis in which match of transition state structure shape and size with that of zeolite cavity becomes important.

For proton catalyzed reactions as well as reactions catalyzed by cation exchanged zeolites pretransition state rearrangement of reacting molecules essentially controls the stereoselctivity. References: 1. R.A. van Santen, Acc. Chem. Res., ASAP Article, 10.1021/ar800022m (2008). 2. R.A. van Santen, M. Neurock, Molecular Heterogeneous Catalysis, Wiley, 2008 3. E.A. Pidko, P. Mignon, P. Geerlings, R.A. Schoonheydt, R.A.van Santen, J. Phys. Chem. 112, 5510 (2008). 4. J.G.O. Ojwang, R.A. van Santen, G.J. Kramer, A.C.T.van Duin, W.A.Goddard III, J. Chem.Phys.

128,164714 (2008).

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Design of New Catalysis Based on Cooperative Pincer-Ligand Systems

David Milstein

Department of Organic Chemistry, The Weizmann Institute of Science, Rehovot 76100, Israel

We have developed a new mode of metal-ligand cooperation, based on reversible de-aromatization of pincer-type ligands, and have designed novel catalytic reactions based on such cooperation, including (a) dehydrogenative coupling of alcohols to form esters and H2

1 (b) hydrogenation of esters to alcohols under mild conditions2 (c) coupling of amines with alcohols to form amides with liberation of H2

3 (d) selective synthesis of primary amines directly from alcohols and ammonia4 (e) direct formation of acetals by dehydrogenative coupling of alcohols5. These reactions are efficient, proceed under neutral conditions, produce no waste and hold promise for organic synthesis. They are catalyzed by pincer-type ruthenium complexes based on pyridine (reactions a-c) and on acridine (reactions d-e), and involve as a key mechanistic step aromatization - de-aromatization of the hetero-aromatic ligand core. Metal-ligand cooperation of this type has led to a distinct approach towards a complete cycle for water splitting, based on consecutive thermal H2 generation and light-induced O2 liberation6.

References (1) Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. J. Am. Chem. Soc. 2005, 127, 10840. (2) Zhang, J.; Leitus, G.; Ben-David, Y.; Milstein, D. Angew. Chem. Int. Ed. 2006, 45, 1113 (3) Gunanathan, C.; Ben-David, Y.; Milstein, D. Science, 2007, 317, 790 (4) Gunanathan, C.; Milstein, D. Angew Chem. Int. Ed. 2008, 47, 8661 (5) Gunanathan, C.; Shimon, L. J. W.; Milstein, D. J. Am. Chem. Soc. 2009, 131, 3146 (6) Kohl, S. W.; Weiner, L.; Schwartsburd, L.; Konstantinovski, L.; Shimon, L. J. W.; Ben-David, Y.; Iron, M.; Milstein, D. Science 2009, 324, 74

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New Rearrangements for the Building of Molecular Complexity via Gold Catalysis

Antonio M. Echavarren,* Eloísa Jiménez-Núñez, Mihai Raducan, Thorsten Lauterbach, Kian Molawi, César R. Solorio

Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona (Spain) [email protected]

Gold(I) complexes are the catalysts of choice for the cyclization of 1,6-enynes and related substrates under mild conditions.1 We have found that, whereas propargyl acetates react undergo 1,2- or 1,3-acetate migration,2 propargyl alcohols, ethers, and silyl ethers 1 react with cationic gold catalysts by a new type of intramolecular 1,5-migration of OR groups.3 This reaction leads stereospecifically to tricyclic compounds 2, which are related to the sesquiterpenes globulol (3a), epiglobulol (3b), and halichonadin F (3c).

HH

H

XH

3a: 4R, X = OH3b: 4S, X = OH 3c: 4S, X = NH2

[Au(I)]

1

H

2

RO

HH

OR

The migration proceeds via allyl-gold cations 4 by a syn-addition of the alkyne and the OR group to the alkene. Thus, gold-catalyzed reaction of 5a with norbornene gave cyclopropane 6, while trapping of the migration intermediate using indole gave adduct 7. Enyne 5b with an allyloxy group gave 8 as a single stereoisomer as a result of a 1,5-migration followed by an intramolecular cyclopropanation.

RO

5a: R = Me5b: R = Allyl

H OMe

8 (65%)

O

HH

H

NH

H

OMeH

6 (75%, dr = 3.2:1) 7 (79%)

indole

[Au(I)][Au(I)]

[Au(I)]

4

AuL

R'

ORH

Acknowledgements. This work was supported by the MICINN (CTQ2007-60745/BQU, Consolider Ingenio 2010, Grant CSD2006-0003), the AGAUR, and the ICIQ Foundation. 1. E. Jiménez-Núñez, A. M. Echavarren, Chem. Rev. 2008, 108, 3326-3350 2. (a) A. Fürstner, P. Hannen, Chem. Commun. 2004, 2546-2547. (b) A. Fürstner, P. Hannen, Chem. Eur. J.

2006, 12, 3006-3019 3. Jiménez-Núñez, E.; Raducan, M.; Lauterbach, T.; Molawi, K.; Solorio, C. R.; Echavarren, A. M. Angew.

Chem. Int. Ed. 2008, 48, 6152-6155.

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Using DFT Calculations for optimizing a catalyst

Odile Eisenstein

Institut Charles Gerhardt, CNRS-Université Montpellier 2, Place Eugène Bataillon 34095 Montpellier, France

Computational studies are currently carried out together with experimental studies to obtain a better understanding of the nature and energy profile of reaction paths. An efficient catalytic cycle is thus associated with a rather flat energy profile without stable intermediates and energetically high transition states. While a perfectly valid condition, this is not sufficient for obtaining an efficient catalytic cycle because secondary unwanted reactions may compete with the main path. The determination of the mechanisms and energy profiles for the main wanted reaction and secondary unwanted reactions is thus needed for a rational design of catalysts. This will be illustrated for olefine metathesis catalysts supported on silica.

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Immobilized Catalysts for Enantioselective Hydrogenation: When will they be used?

B. Pugin

Solvias AG, Catalysis Research, R-1060.P18, CH-4002 Basel. [email protected]

A modular approach for the immobilization of catalysts by covalent binding and for the preparation of extractable / water soluble catalysts will be presented and illustrated with the story of S-Metolachlor, an important herbicide which today is produced in a >10'000 t/y scale with a homogeneous Ir-catalyst. In addition, factors such as the type of support, the pore size, the catalyst surface loading that can influence the properties of immobilized catalysts will be discussed. It will be shown that immobilized catalysts with properties that are of industrial interest can be prepared but that these catalysts tend to be substantially more complex and expensive than their homogeneous counterparts.

To the best of our knowledge, there are not yet examples for the use of immobilized metal complex catalysts in industrial processes. The second part will therefore address the question ‘When and where will immobilized catalysts be used in industry?’. Different methods for the preparation of catalysts that can be separated by filtration or extraction will be discussed and assessed from our personal view. In our opinion, decisive factors will be e.g.

- demand for homogeneous catalysis, - benefit of immobilization, - ease of access to and costs of immobilized catalysts - catalytic properties of immobilized catalysts

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Directed Evolution of Enzymes: New Biocatalysts for Organic Synthesis

Nicholas J. Turner

School of Chemistry, University of Manchester, Manchester Interdisciplinary Biocentre, 131 Princess Street, Manchester, M20 3DH, UK. E-mail: [email protected]

The ability to change, and improve upon, the properties of a biocatalyst using directed evolution techniques has emerged as a powerful strategy in the past 10 years. By employing appropriately designed high-throughput screening methods, coupled with random mutagenesis to generate large libraries of enzyme variants, it is possible to identify biocatalysts with broader substrate tolerance, improved enantioselectivity and importantly enhanced properties (e.g. turnover, thermostability, solvent stability) when operating under process conditions. This lecture will review the state-of-the-art in this area, including examples from our own laboratory, in which a range of different enzymes (e.g. amine oxidases [1-5], alcohol oxidases [6-7], racemases, ammonia lyases, P450 monooxygenases [8] and transaminases [9]) have been subjected to directed evolution to change one or more properties. A key focus has been the development of deracemisation reactions, or their equivalent, in which chiral amines, alcohols and amino acids are obtained in high yield and enantiomeric excess. References [1] R. Carr, M. Alexeeva, A. Enright, T.S.C. Eve, M.J. Dawson and N.J. Turner, Angew. Chem. Int. Ed., 2003, 42,

4807-4810. [2] R. Carr, M. Alexeeva, M.J. Dawson, V. Gotor-Fernández, C.E. Humphrey and N.J. Turner, ChemBioChem,

2005, 6, 637-639. [3] C.J. Dunsmore, R. Carr, T. Fleming and N.J. Turner, J. Am. Chem. Soc., 2006, 128, 2224-2225. [4] T.S.C. Eve, A.S. Wells and N.J. Turner, Chem. Commun., 2007, 1530-1531. [5] K.R. Bailey, A.J. Ellis, R. Reiss, T.J. Snape and N.J. Turner, Chem Commun., 2007, 3640-3642; K.E. Atkin,

R. Reiss, V. Koehler, K.R. Bailey, S. Hart, J.P. Turkenburg, N.J. Turner, A.M. Brzozowski and G. Grogan, J. Mol. Biol., 2008, 384, 1218-1231.

[6] F. Escalettes and N.J. Turner, ChemBioChem, 2008, 9, 857-860. [7] M.D. Truppo, F. Escalettes and N.J. Turner, Angew. Chem. Int. Ed., 2008, 47, 2639-2641. [8] A. Robin, G.A. Roberts, J. Kisch, F. Sabbadin, G. Grogan, N. Bruce, N.J. Turner and S.L. Flitsch, Chem.

Commun., 2009, 2478-2480. [9] M.D. Truppo, N.J. Turner and J.D. Rozzell, Chem. Commun., 2009, 2127-2129; M.D. Truppo, J.D. Rozzell,

J.C. Moore and N.J. Turner, Org. Biomol. Chem., 2009, 7, 395-398.

PL-12

24

Monofunctional, Bifunctional and Trifunctional Single-Site Solid Catalysts

John Meurig Thomas and Robert Raja

Dept. of Materials Science, University of Cambridge, CB23QZ, School of Chemistry, Southampton University, SO17

A general strategy for designing monofunctional single-site heterogeneous catalysts(SSHCs), of the kind shown in the accompanying diagram, in which active centers are either anchored to or constitute an integral part of the framework of the inner walls of nanoporous silica or high-area aluminas, has been available for some time[1-4]. With such catalysts many organic conversions of intrinsic chemical novelty or of industrial importance may be carried out under environmentally benign conditions. These include: the production of nicotinonitrile or nicotinic acid (vitamin B3); the reduction of 5-hydroxymethyl furfural (HMF) to the potential biofuel, 2,5-dimethyl furan(DMF); styrene to styrene oxide, paraxylene to terephthalic acid; and benzyl alcohol to benzaldehyde, as well as many others- [1,2].

Immobilization of many organometallic catalysts, like the Grubbs Ru-carbenes, also show promising results that should reap the benefits of heterogenizing for ring-closing and ring-opening reactions [5].

Until very recently, there was great difficulty[6,7] in routinely preparing chiral, open-structure catalysts that should facilitate production of enantiopure fine chemicals. Significant progress has been made by Lin[8], Bu[9] and others (see references in[7]) in producing homochiral solids. Good enantioselective performance of monofunctional MOF (metal-organic frameworks) has been reported in the hydrogenation of prochiral ketones[8]. And when chiral organometallic catalysts are anchored inside nanoporous silicas, where spatial congestion is pronounced, many high–performance enantioselective processes (e.g. methyl benzyl-forma [10,11]te to methyl mandelate) are possible .

An example of bifunctional SSHC entails the use of microporous MALPOs (metal-ion, framework substituted alumino phosphates), where a redox site and a Bronsted one are juxtaposed in the same cavity, thereby enabling the formation of hydroxylamine in situ and its acid-catalyzed reaction of cyclohexanone to form the oxime[12]. Trifunctional SSHCs are typified by the conversion of ethene to propene (invoving dimerization, isomerization and metathesis) over catalysts such as Ni-MCM-41 (reported by Iwamoto[13] and anchored WH3 groups by Taoufik et al [14]. Another example is the production of caprolactam (the precursor of nylon-6) in a trifunctional MALPO catalyst[12].

[1] J.M. Thomas et al, Topics in Catalysis 2009, 52, 1630. [2] J.M. Thomas et al, PhysChemChem Phys 2009, 11, 2799. [3] J.M. Thomas, J. Chem. Phys. 2008, 128, 182502. [4] J.M. Thomas, R. Raja and D.W. Lewis, Angewandte Chemie 2005, 44, 6456. [5] H.Balcar et al, Topics in Catalysis (in press). [6] J.Sun et al, Nature 2009, 458, 1154. [7] K.D.M. Harris and J.M. Thomas, ChemCatChem 2009, 1, in press [8] L.Mac.Abney and W.Lin, Chem. Soc. Rev. 2009, 38, 1248

[9] J.Zhang,S.Chen and X.Bu, Angewandte Chemie 2009, 48, 6099 [10] J.M. Thomas and R.Raja, Acc .Chem. Res. 2008, 41, 708 [11] C.Li et al, Chem. Commun. 2007, 547 [12] J.M. Thomas and R.Raja, PNAS 2005, 102, 13732 [13] M.Iwamoto and Y.Kosugi, J. Phys. Chem. C 2007,111, 13 [14] M.Taoufik, E.Leroux, J.Thivolle-Cazat and J.M. Basset, Angewandte Chemie 2007, 46, 7202

PL-13

25

26

Keynote lectures

KL1-KL10

27

28

Dinitrogen Dissociation on an Isolated Surface Tantalum Atom

E. A. Quadrellia,* P. Avenier,a M.Taoufik,a,* A. Lesage,b X. Solans-Monfort,c L. Veyre,a A. Baudouin,a A. de Mallmann,a O. Eisenstein,d,* J.-M. Basset,a,* L. Emsley.b

a Université de Lyon, ICL, UMR 5265 C2P2 CNRS- Université Lyon 1- CPE-Lyon, LCOMS, 43 Blvd du 11 Novembre 1918, BP 2077 69616, Villeurbanne, France.

b Centre de RMN à Très Hauts Champs, Université de Lyon, CNRS-ENS Lyon – UCBL1, 69100 Villeurbanne, France.

cDepartament de Química, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. d Institut Charles Gerhardt, CNRS- ENSCM, UM1, Université Montpellier 2, F-34095 Montpellier France.

Both industrial and biochemical ammonia syntheses, producing both over 108 T/an of NH3, are thought to rely on the cooperation of multiple metals in breaking the strong triple bond of dinitrogen. Such multimetallic cooperation for dinitrogen cleavage is also the general rule for dinitrogen reductive cleavage with molecular systems.[1] We have observed the unprecedented cleavage of dinitrogen by dihydrogen at 250°C and atmospheric pressure on isolated silica surface–supported TaIII and TaV hydride centers [(≡SiO)2TaH] and [(≡SiO)2TaH3], leading to the TaV amido imido product [(≡SiO)2Ta(=NH)(NH2)].

We assigned the product structure based on extensive characterization by IR and solid-state NMR, isotopic labeling studies, supporting data from EXAFS and theoretical simulations, and by comparison with the product directly obtained from ammonia. Reaction intermediates revealed by in situ IR monitoring of the reaction support a mechanism highly distinct from those previously observed in enzymatic, organometallic, and heterogeneous N2 activating systems. A mechanism will be proposed based on DFT studies and catalytic H/D exchanges studies.[4]

OTa

SiO

Si

H

SiO

O

O

HH2

OTa

Si

H H

H

O

Si

HSi

O

O

O+ NH3

+ N2+H2

OSi

OTa

Si

NHH2N

NH2/H

OOSi

O

(RT, 3h)

(250°, 4dd)

or

either

____ [1] (a) A. Nielsen, Ed. “Ammonia: Catalysis and Manufacture” (Springer Verlag, Berlin, 1995). (b) R. R.

Schrock, forward of Nitrogen Fixation Special Issue, Proc. Natl. Acad. Sci. U.S.A. 103 (2006). (c) D. V. Yandulov, R. R. Schrock, Science 301, 76 (2003).

[2] P. Avenier, M. Taoufik, A. Lesage, X. Solans-Monfort, A. Baudouin, A. de Mallmann, L. Veyre, J.-M. Basset, O. Eisenstein, L. Emsley, E. A. Quadrelli Science 317, 1056-1060 (2007).

[3] P. Avenier, A. Lesage, M. Taoufik, A.Baudouin, A. De Mallmann, S. Fiddy, M. Vautier, L. Veyre, J.-M. Basset, L. Emsley, and E. A. Quadrelli, J. Am. Chem. Soc. 129(1), 176-186 (2007).

[4] P. Avenier, X. Solans-Monfort, L. Veyre, F. Renili, J.-M. Basset, O. Eisenstein, M. Taoufik, and E. A. Quadrelli Topics in catalysis, Special Issue “Nitrides, oxynitrides and nitrogen containing materials”, published online 27 May (2009).

KL-1

29

Biphasic and flow systems involving water or supercritical fluids

David J. Cole-Hamiltona, Simon L. Desseta, Ruben Duquea, Eva Öschnera, Steven P. Nolan a, Herve Claviera and Marc Auduitb

a EaStCHEM, School fo Chemistry, University of St. Andrews, St. Andrews, Fife, KY16 9ST b Ecole Nationale Supérieure de Chimie de Rennes, Av. du Général Leclerc, 35700 Rennes, France.

The separation of catalysts from the solvent and reaction products remains one of the major problems of homogeneous catalytic reactions, which are otherwise advantageous because of their high activity, tuneable selectivity and ease of study. In recent years a large number of different strategies has been employed to address this problem, ranging from the use of soluble and insoluble supports, sometimes with ultrafiltration, to the application of biphasic systems.1, 2 Ideally, the reactions would be carried out in continuous flow mode with the catalyst remaining in the reactor at all times, whilst the substrates and products flow over the catalyst. A variety continuous flow reactions has been proposed.3 In this presentation we shall highlight the use water as a benign solvent, discussing new strategies for obtaining high rates in aqueous biphasic catalysis with fast separation and good catalyst retention.4, 5 We shall also discuss continuous flow processes involving supported ionic liquid phase catalysts, over which the substrates flow dissolved in supercritical carbon dioxide (scCO2). The products are also removed by the flowing scCO2 stream.6

The low solubility of hydrophobic compounds in water makes aqueous biphasic reactions involving them slow because of mass transport limitations. By adding compounds such as 1-octyl-3-methyl imidazolium bromide, we have been able to increase the reaction rates by almost 2 orders of magnitude whilst retaining fast phase separation and low catalyst leaching to the products phase. Evidence will be presented that the additives act as weak surfactants, increasing the interfacial surface area, but breaking as soon as the stirring is stopped.

In an alternative approach, “switchphos” ligands have been developed which allow the catalytic reaction to be carried out in the organic phase, but which transport the catalyst into water on bubbling CO2. After phase separation and replacement of the organic phase, the catalyst can be switched back into the organic phase by bubbling N2 with gentle heating. This process allows the reactions to be carried out at very high rates with the catalyst being very efficiently separated from the products and recycled.

For the flow systems, the catalyst is supported within a thin film of an ionic liquid supported within the pores of a microporous silica. Substrates and products flow through the system dissolved in scCO2. Futher details are available in the poster abstract of Ruben Duque.

Fig. 1. Reversible CO2 phase switching for catalyst recovery during the hydroformylation of 1-octene

1. D. J. Cole-Hamilton, Science, 2003, 299, 1702. 2. D. J. Cole-Hamilton and R. P. Tooze, eds., Catalyst Separation, Recovery and Recycling; Chemistry and

Process Design, Springer, Dordrecht, 2006. 3. D. J. Cole-Hamilton, T. E. Kunene and P. B. Webb, in Multiphase Homogeneous Catalysis, ed. B. Cornils,

Wiley VCH, Weinheim, 2005, vol. 2, pp. 688. 4. S. L. Desset and D. J. Cole-Hamilton, Angew. Chem. Int. Ed., 2009, 48, 1472. 5. S. L. Desset, S. W. Reader and D. J. Cole-Hamilton, Green Chem., 2008, 11, 630. 6. U. Hintermair, G. Y. Zhao, C. C. Santini, M. J. Muldoon and D. J. Cole-Hamilton, Chem. Commun., 2007,

1462.

KL-2

30

Dynamic Kinetic Resolution with heterogeneous and biocatalysts: Concepts and applications to fine chemicals synthesis

Dirk De Vos, Stijn Wuyts, Andrei Parvulescu, Joost Janssens and Pierre Jacobs

Centre for Surface Chemistry and Catalysis, K.ULeuven Kasteelpark Arenberg 23, 3001 Leuven, Belgium

Dynamic kinetic resolution (DKR) is an elegant method to convert racemic reagents to enantiopure compounds in a single step. It overcomes the 50% yield limitation of classical kinetic resolution by combining the enzymatic resolution catalyst (usually an enzyme) in one pot with a racemization catalyst. As trivial as racemization of a chirally pure compound might seem, the key issue is to avoid undesired transformations to products other than its enantiomer. Additionally, when combined in one reaction mixture, neither the resolution catalyst nor the racemization catalyst should influence the other catalysts' activity or selectivity.

In groundbreaking work, Bäckvall and others have used homogeneous coordination compounds, in particular of ruthenium, as racemization catalysts for DKR of alcohols or amines.1 Since recuperation and re-use of the homogeneous catalyst is not always a simple task, we have explored the potential of various classes of heterogeneous catalysts in DKR. A main advantage is that enzyme deactivation by dissolved metal complexes is completely excluded when truly heterogeneous catalysts are used.

For racemic secondary alcohols as reagents, we discovered various efficient racemization catalysts, such as Ru immobilized on hydroxyapatite, acid zeolites, or insoluble VOSO4.2 Side reactions that can be efficiently suppressed during the racemization are the formation of ketones, or the dehydration followed by oligomerization. With acid zeolites as the racemization catalyst, we developed a two-phase reaction system, with the zeolite as the racemization catalyst and an immobilized lipase as the resolution catalyst. Enantiopure esters were obtained in over 90% yield with > 99% ee. Importantly, since both catalysts are solids, the complete catalytic system is very easy to re-use. The racemization proceeds via carbenium ion intermediates, not only for these acid zeolites, but also for VOSO4, which is a surprizingly active alcohol racemization catalyst.

DKR of secondary amines faces similar selectivity issues, for instance with undesired formation of secondary amines. We demonstrated that Pd catalysts are suitable for the racemization, at least when supported on neutral to basic supports like CaCO3 or aminopropylated silica. For the tough DKR of aliphatic amines, even a classical standard material like Raney Ni appears to be suitable.

Finally, we will demonstrate the applicability of this methodology to DKR of homoserinelactones. Acylated homoserinelactones are capable of interfering with bacterial communication and are therefore promising alternatives to antibiotics.

1. O. Pamiès, J. E. Bäckvall, Chem. Rev., 10 (2003) 3247. 2. Wuyts, De Vos, et al., J. Catal. 219 (2003) 417; Wuyts, De Vos, et al., Chem. Eur. J. 11 (2004) 386; Wuyts,

De Vos, et al., Chem. Commun. 15 (2003) 1928; Wuyts, Wahlen, De Vos, Green Chem. 9 (2007) 1104. 3. Parvulescu, De Vos, Jacobs, Chem. Commun. (2005) 5307; Parvulescu, Jacobs, De Vos; Chem. Eur. J. 13

(2007) 2034; Parvulescu, De Vos, J. Catal. 255 (2008) 206; Adv. Synth. Catal. 350 (2008) 113; Appl. Catal. A, in the press.

KL-3

31

Development of Catalysts for Hydrogen Generation Matthias Beller

Leibniz-Institut für Katalyse e.V. an der Universität Rostock Albert-Einstein-Straße 29a, 18059 Rostock

[email protected]

The sufficient and sustainable supply of energy remains one if not the most important challenge for our future. Clearly, the development of technologies which allow for the replacement of contemporary fuels which are based on fossil resources is an important task for all scientific disciplines. In this respect advancements in hydrogen technology are of particular interest, since hydrogen allows for an efficient conversion of chemical into electrical energy via fuel cells, which proceeds in principle waste free with water as the only product. Catalysis might be one of the key technologies to generate hydrogen in a sustainable

manner! In the talk the catalytic generation of hydrogen from potential hydrogen storage materials such as formic acid will be presented. Molecular-defined catalysts have been developed, which allow for the professional generation of hydrogen at ambient conditions.1 1. a) B. Loges, A. Boddien, H. Junge, M. Beller, Angew. Chem. Int. Ed. 2008, 47, 3962-3965; b) B. Loges, A. Boddien, J. Noyes, H. Junge, M. Beller, Chem. Commun. 2009, in press.

KL-4

32


Unique Catalytic Chemistry of the Nano-confined Systems

Xinhe Bao

State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, the Chinese Academy of Sciences, Dalian 116023, P. R. China

In the present presentation, the unique characters of the catalysis with the nano-confined systems will be demonstrated, and the emphasis will be laid on the variation of the electron properties derived from the quantum well states in the 2-D nano film and the confinement effects in the interface between the nano-islands of the oxides and noble metallic substrates.

The effect of electron quantum confinement on the catalytic activities of 2D ultra-thin metal films is explored by comparing the work function change and the initial reaction rate of atomically flat films of different thickness of lead layers on silicon surfaces, using complementary microscopy and spectroscopy techniques. The obvious oscillations of the oxidation rate of lead films are observed, which are attributed to be a manifestation of the Fabry-Pérot interference modes of electron de Broglie waves (quantum well states) in the films. The modulation of the electron density of states near the Fermi level opens a new dimension for tuning the catalytic performance of metal systems via size- and thickness-dependent quantum size effects, which will be illustrated through two examples.

Coordinatively unsaturated iron species, especially those in low valent states, are pivotal for the activation of oxygen-containing reactants. As a result, highly active oxygen species are generated which are essential for the selective oxidation reactions. In the present, we will demonstrate a novel concept to construct a unique high active Fe-oxo species on noble metal surfaces through a structural confinement derived by the strange interaction. The Fe atoms at the edges of the structures show the nature of the coordinatively unsaturated low-valent state, i.e. FeO1-x, at which the adherence of molecular oxygen is remarkably enhanced, and the dissociation of the adsorbed dioxygen presents a barrierless character. The preferential formation of desiccative oxygen species at the boundary of Fe-oxo inland modifies essentially the adsorption dynamics between the carbon monoxide and oxygen, which causes a dramatically change of the catalytic performance towards oxidation of carbon monoxide on the surface. An integrated test of the real catalyst with 1 kw PEM fuel cell for 1000 hours shows that under the operating condition, with 20% water steam, 30ppm of CO in the reforming hydrogen can be completed removed.

Selected Publications: 1. Teng Ma, Qiang Fu*, Hai-Yan Su, Hong-Yang Liu, Yi Cui, Zhen Wang, Ren-Tao Mu, Wei-Xue Li, and Xin-He Bao*, CHEMPHYSCHEM, 10(2009)1013-1016 2. Rentao Mu, Qiang Fu, Hongyang Liu, Dali Tan, Runsheng Zhai, and Xinhe Bao, Appl. Surf. Sci., 255(2009)7296-7301 3. Junming Sun and Xinhe Bao, CHEMISTRY-A EUROPEAN JOURNAL (Invited Concept article), (2008)(14)7478-7488 4. Hui Zhang, Qiang Fu, Yunxi Yao, Zhen Zhang, Teng Ma, Dali Tan, Xinhe Bao, Langmuir, 24(2008)10874-10878 5. Hai-Yan Su, Xin-He Bao, and Wei-Xue Li, J. Chem. Phys., 128(2008)194707 6. Xucun Ma, Peng Jiang, Yun Qi, Jinfeng Jia, Yu Yang, Wenhui Duan, Wei-Xue Li, Xinhe Bao, S. B. Zhang and Qi-Kun Xue, P NATL ACAD SCI USA (PNAS), 104(2007)(22)9204-9208 7. Junming Sun, Ding Ma, He Zhang, Xiumei Liu, Xiuwen Han, Xinhe Bao*, Gisela Weinberg, Norbert Pfaender, Dangsheng Su, J. Am. Chem. Soc., 128 (49) (2006) 15756-15764

KL-5

33

C—H: A New Functional Group for Streamlining Synthesis

M. Christina White*

Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, IL 61801, USA

Among the frontier challenges in chemistry in the 21st century are (1) increasing control of chemical reactivity and (2) synthesizing complex molecules with higher levels of efficiency. Although it has been well demonstrated that given ample time and resources, highly complex molecules can be synthesized in the laboratory, too often current methods do not allow chemists to match the efficiency achieved in Nature. This is particularly relevant for molecules with non-polypropionate-like oxidation patterns (e.g. Taxol). Traditional organic methods for installing oxidized functionality rely heavily on acid-base reactions that require extensive functional group manipulations (FGMs) including wasteful protection-deprotection sequences. Due to their ubiquity in complex molecules and inertness to most organic transformation, C—H bonds have typically been ignored in the context of methods development for total synthesis.

R

H

robust latentfunctionality

OAc

O O

alkyl

Br

O

ONHBoc

13 examplesJACS 2006, 128, 9032

>50 examplesJACS 2005, 127, 6970;

2006, 128, 15076; 2008, 130, 11270; ACIE 2008, 47, 6448

17 examplesJACS 2004, 126, 1346

OL 2005, 7, 223ACIEE 2006, 45, 8217

OBn

OBn

NTsO

O

8 examplesJACS 2007, 129, 7274.

H

highly robust latentfunctionality

OO

OBnNTs

CO2Me

N

N

N

Me

OO

O

On = 4 n = 2

15 examplesJACS 2008, 130, 3316.

n = 2

NH

AcO

OH

O

F3C21 examples

Science 2007, 318, 783.

3o C—H Oxidation

Linear C—HOxidation

Linear C—H Amination

Branched C-H Oxidation/Oxidative Heck

OxidativeMacrolactonization

Branched C-HAmination

OO

Science 2007, 318, 783.

AliphaticLactonization

C-HAlkylation

OR

Me

NN

N CO2Me

NO2

25 examplesJACS 2008, 130, 14090

Highly selective oxidation methods, similar to those found in Nature, for the direct installation of oxygen, nitrogen and carbon functionalities into allylic and aliphatic C—H bonds of complex molecules and their intermediates will be discussed. Unlike Nature which uses elaborate enzyme active sites, we rely on the subtle electronic and steric interactions between C—H bonds and small molecule transition metal complexes to achieve high selectivities. Our current understanding of these interactions gained through mechanistic studies will be discussed. Novel strategies for streamlining the process of complex molecule synthesis enabled by these methods will be presented. Collectively, we aim to change the way that complex molecules are constructed by redefining the reactivity principles of C—H bonds in complex molecule settings.

KL-6

34

Green Oxidation Reactions by Polyoxometalate-Based Catalysts: From Molecular to Solid Catalysts

Noritaka Mizuno*

Department of Applied Chemistry, School of Engineering, The University of Tokyo 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan

Oxidation reactions are very important in industry and the developments of highly atom-efficient catalytic selective oxidation processes with environmentally friendly H2O2 or O2 (air) have extensively been demanded. Recently, the catalytic functions of polyoxometalate (POM)-based compounds for the oxidation reactions have attracted much attention because their properties can be controlled at atomic/molecular levels.

We succeeded in the developments of highly atom-efficient catalytic systems for efficient green oxidations of alkanes, alkenes, and alcohols with hydrogen peroxide or molecular oxygen by fine design and synthesis of novel POM-based molecular catalysts. For example, lacunary POM TBA4[γ-SiW10O34(H2O)2] (TBA = tetra-n-butylammonium) catalyzed the epoxidation of common alkenes and sulfides using hydrogen peroxide with perfect epoxide selectivity and H2O2 utilization.[1] Transition metal-substituted POM TBA4[γ-SiV2W10O38(μ-OH)2][2] and TBA4[γ-H2SiW10O36Cu2(μ-1,1-N3)2][3] catalyzed the chemo-, regio-, and diastereoselective epoxidation of alkenes and the aerobic oxidative alkyne-alkyne homocoupling, respectively.

We synthesized the organic-inorganic hybrid support by covalently anchoring N-octyldihydroimidazolium cation fragment onto SiO2.[4,5] The above POM-based molecular catalysts could be immobilized on the support via the anion exchange. The supported catalysts showed high performance for the oxidations without the loss of their intrinsic catalytic nature of the corresponding homogeneous analogues. In addition, we have developled supported metal hydroxide catalysts with on the basis of the information of the catalytically active sites with POM. For example, the monomerically dispersed ruthenium hydroxide catalyst was found to act as an efficient heterogeneous catalyst for the aerobic oxidations of various substrates including alcohols,[6,7] amines,[8,9] alkylarenes,[10] and 2-naphthols.[11]

Synthesis of POM-Based Molecular Catalysts

Immobilization Extraction of Active Sites

Lewis acid

References [1] Science, 2003, 300, 964-966. [2] Angew. Chem. Int. Ed., 2005, 44, 5136-5141. [3] Angew. Chem. Int. Ed., 2008, 47, 2407-2410. [4] J. Am. Chem. Soc., 2005, 127, 530-531. [5] Chem. Eur. J., 2006, 12, 4176-4184. [6] Angew. Chem. Int. Ed., 2002, 41, 4538-4542. [7] Angew. Chem. Int. Ed., DOI: 10.1002/anie.200900418. [8] Angew. Chem. Int. Ed., 2003, 42, 1480-1483. [9] Angew. Chem. Int. Ed., 2008, 47, 9249-9251. [10] Org. Lett., 2004, 6, 3577-3580. [11] J. Am. Chem. Soc., 2005, 127, 6632-6640.

Figure 1. Design of polyoxometalate-based catalysts.

Brønsted base

supportM

OH

OH

OH

OH

OH

OH

OH

OH

OH OO

SiO

N

N+

OOSi

O

N

N+

O OSi

O

N

N+

O OSi

O

N

N+

O OSi

N

N

O

+

O OSi

N

N

OO O

Si

N

N

O

+

OOSi

N

N

O

+

OOSi

N

N

OOO

Si

N

N

O

+

OH

OH

OH

OH

OH

OH

OH OH

OH

OH

OH

OH

OHO

H

SiO2

KL-7

35

Heterogenized M-Salen Catalysts for Enantioselective Reactions: Catalyst Design, Structure-Reactivity Trends, and Deactivation

Pathways

Christopher W. Jones

School of Chemical & Biomolecular Engineering, School of Chemistry and Biochemistry, Georgia Institute of Technology, 311 Ferst Dr., Atlanta, GA 30332, USA

*Affilitation for Fourth Author

Metal salen complexes are widely applied as catalysts for numerous important enantioselective reactions. The reactions catalyzed by metal salen complexes generally follow either (i) monometallic mechanisms (e.g. Mn-salen for epoxidation or Ru-salen for cyclopropanation), whereby a single metal complex promotes the catalytic reaction or (ii) bimetallic mechanisms, where cooperation between two metal complexes is required for efficient catalysis (e.g. Co-salen for epoxide ring-opening or Al-salen conjugate additions of cyanide). The design of effective heterogenized catalysts should therefore take into account the reaction mechanism, as reactions in category (i) are hypothesized to be optimized by accessible yet isolated supported metal salen complexes, whereas reactions of type (ii) are hypothesized to require efficient complex mobility, facilitating metal salen – metal salen cooperative interactions.

Here, several new designs for (a) soluble polymer or oligomer supported metal salen complex catalysts, (b) insoluble polymer resin supported complexes, and (c) insoluble porous silica supported are reported. Their utility in the cooperative Co-salen catalyzed hydrolytic kinetic resolution of epoxides and the monometallic Ru-salen catalyzed enantioselective cyclopropnantion of olefins is reported. The kinetics of the reactions using both fresh and recycled catalysts are compared. Most catalysts are shown to deactivate during use, and the mechanisms of deactivation are explored. Strategies to reduce or mitigate catalyst deactivation are explored.

KL-8

36

In-situ microscopy and spectroscopy for structural and catalytic studies

M. Salmeron

Lawrence Berkeley National Laboratory and Materials Science and Engineering Dept. University of California, Berkeley. CA 94720. USA

Over the last decades my laboratory has developed and applied microscopy and spectroscopy techniques for in situ studies of the surface structure of catalysts in the presence of various gases. These include high pressure Scanning Tunneling Microscopy (HP-STM), in situ x-ray spectroscopies, including high pressures x-ray absorption (XAS) and X-ray photoelectron spectroscopy (HP-XPS). We applied these techniques to the study of various reactions and surfaces on single crystals and nanoparticles. I will illustrate the capabilities of these techniques with several examples. These include the restructuring of Pt single crystals in the presence of CO, the structure of Rh(111) in the presence of CO and NO, the determination of the surface phase diagram of Pd oxides in equilibrium with O2, and others. In the area of nanoparticles, I will show the application of XAS and HP-XPS to study the structure and activity of Co nanoparticles for CO+H2 methanation as a function of particle diameter from 3 to 20 nm. The particles Co were found to remain metallic and covered by CO during reaction. The reactivity per Co atom was found to decrease when the particle size became smaller than 10 nm, an effect that was related to the decreased activity of the particles to dissociate H2, while the rate limiting step did not change. Using HP-XPS also we observed the structural modifications of core-shell Rh-Pd and Rh-Pt alloy nanoparticles during oxidative and reducing conditions.

KL-9

37

Chiral Metal-Organic Frameworks for Asymmetric Catalysis

Wenbin Lin

Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599, USA. [email protected]

The chemistry of hybrid solids constructed from organic linkers and metal nodes has received much recent attention, owing to the propensity of incorporating and fine-tuning desired properties via judicious choices of their building blocks. The Lin group has explored the rational design of functional solids based on metal-organic frameworks (MOFs) over the past few years, with particular focuses on applying MOFs in nonlinear optics,1 hydrogen storage,2 biomedical imaging,3 and drug delivery.4 In this lecture, I would like to discuss our recent success in the design and synthesis of chiral porous MOFs by connecting metal nodes with chiral bridging ligands that have orthogonal functionalities. Two complementary strategies have been successfully utilized to synthesize catalytically active chiral MOFs. In the first approach, the primary functional groups are linked by metal-connecting units to form extended networks whereas the orthogonal secondary chiral groups can then be used to generate asymmetric catalytic sites by coordinating to a secondary metal center (Figure 1). Such chiral porous MOFs have been shown to provide excellent catalysts for the additions of diethylzinc and alkynylzinc to aromatic aldehydes with very high enantioselectivities.5,6 In the second approach, the primary functional groups are used to generate robust transition metal precatalysts which are then linked by the metal nodes to form porous extended networks via the secondary functional groups.7,8 These chiral porous solids have been used for highly enantioselective asymmetric reduction of unsaturated substrates such as ketones and ketoesters as well as oxidation reactions of alkenes. The present complementary synthetic strategies have thus led to ideal heterogeneous asymmetric catalysts in which both the catalytic sites and the secondary environments around them are identical throughout the solid. In comparison to other immobilization approaches, the present strategy allows the synthesis of heterogeneous asymmetric catalysts with higher catalyst loading and more accessible catalytic centers.

Figure 1

REFERENCES

[1] Evans, O.R.; Lin, W. Acc. Chem. Res. 2002, 35, 511-522. [2] Kesanli, B.; Cui, Y.; Smith, M.; Bittner, E.; Bockrath, B.; Lin, W. Angew. Chem. Int. Ed. 2005, 44, 72-75. [3] Taylor, K.M.L.; Rieter, W.J.; Lin, W. J. Am. Chem. Soc. 2008, 130, 14358-14359. [4] Rieter, W.J.; Pott, K.M.; Taylor, K.M.L.; Lin, W. J. Am. Chem. Soc. 2008, 130, 11584-11585. [5] Wu, C.-D.; Hu, A.; Zhang, L.; Lin, W. J. Am. Chem. Soc. 2005, 127, 8940. [6] Wu, C.-D.; Lin, W. Angew. Chem. Int. Ed. 2007, 46, 1075-1078. [7] Hu, A.; Ngo, H.L.; Lin, W. J. Am. Chem. Soc. 2003, 125, 11490 [8] Ma, L.; Abney, C.; Lin, W. Chem Soc. Rev. 2009, 38, 1248-1256.

KL-10

38

Oral contributions

OC1-OC38

39

40

Exploring a New Paradigm in Immobilization of Multicomponent Asymmetric Catalyst

Hiroaki Sasai*, Shinobu Takizawa, Mahesh L. Patil and Kazuyoshi Marubayashi

The Institute of Scientific and Industrial Research (ISIR), Osaka University 8-1 Mihogaoka, Ibaraki-shi, Osaka 567-0047, Japan

Several methodologies for the immobilization of multicomponent asymmetric catalysts (MAC), which consist of plural molecules of ligands and metals, have been developed. In the first place, MACs such as Al-Li-bis(binaphthoxide) and/or Ga-Na-bis(binaphthoxide) catalyst (ALB and GaSB, respectively) were introduced to dendrimers and soluble polymers containing dendron units (Figure 1).1 The immobilized catalysts showed comparable catalytic activity and enantioselectivity to those of parent homogeneous catalysts. Since dendritic molecules require multi-step synthesis, efficient usage of nanoparticles derived from either a micelle-derived polymer (MDP) or a monolayer-protected metal cluster was examined. Secondly, we found that “catalyst analog” is effective to position the ligands suitably to construct MAC on the polymer backbone (Figure 2).1-2 Thirdly, utilizing metal-bridged polymers, a simple and efficient method for immobilization of MAC without the need for a polymer support has been realized (Figure 3). Heterogeneous ALB, GaSB and μ-oxodititanium complexes thus obtained have been used as catalysts for the enantioselective Michael addition and the carbonyl-ene reactions, respectively. The metal-bridged polymer catalysts displayed high activity affording the corresponding products with high enantiocontrol.1-3

MAC Catalyst analogR

Copolymerization

-

+

: Connecting group or element: Metal or functional group

R',

Figure 2. Immobilization of MAC using catalyst analog.

LiAlH4

HOHO

OHOH

THF

O

O

O

OAl

Li

O

OAl

O

OAl

Li

Al-bridged Polymer(R,R)-6,6'-Bi(BINOL)

Figure 3. Synthesis of Al-bridged polymer catalyst.

1) Takizawa, S.; Arai, T.; Sasai, H. J. Synth. Org. Chem. Jpn. 2009, 67, 194. 2) Takizawa, S.; Patil, M. L.; Marubayashi, K.; Sasai, H. Tetrahedron, 2007, 63, 6512. 3) Takizawa, S.; Somei, H.; Jayaprakash, D.; Sasai, H. Angew. Chem. Int. Ed. 2003, 42, 5711.

OC-1

41

Hydroformylation of Olefins over Immobilized Rh-P Complex Catalysts

Wei Zhou, Dehua He*

Innovative Catalysis Program, Key Lab of Organoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, P.R. China

Hydroformylation of olefin is an important reaction to synthesize aldehydes or alcohols. Industrial catalysts for hydroformylation are cobalt- or rhodium-based homogeneous complexes, which suffer from difficult catalyst separation[1]. In the present paper, Rh-P complex was anchored to ordered mesoporous silica SBA-15 by using n-alkyls (C1∼C11) as connection spacers. The prepared immobilized catalysts were employed in the hydroformylation of several olefins and the recycle use of the catalysts was also examined.

The preparation of SBA-15-anchored Rh-P complex catalysts by using n-alkyls as connection spacers and RhCl3 as precursor is described in our previous work[2]. The catalysts were characterized by infrared spectroscopy (IR), isothermal N2 sorption analysis, X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and inductive coupling plasma-atomic emission spectroscopy (ICP-AES). XPS indicated Rh(III) was reduced to Rh(I) after immobilization. On the IR spectra of the immobilized catalysts, stretching of carbonyl[3] was observed at 1969 cm-1

. Hydroformylation was carried out in a 100 mL autoclave under the reaction conditions of 393 K, 5.0 MPa syngas pressuer and 2.5 h with 5 mL substrate and 15mL toluene as solvent. Rh leaching in the reaction liquids was determined by ICP-MS.

The immobilized catalysts showed relatively high activity and selectivity in the hydroformylation of 1-hexene, 1-octene, 2-octene and 1-decene. The immobilized catalysts were stable in the recycle use and Rh leaching into the reaction liquids was found very low. The length of the alkyl spacers has a great effect on the activity of the immobilized catalysts. With the increase of alkyl spacer length, the specific activity of the catalysts increased. The immobilized catalyst using longer alkyl (n-C11) as spacer revealed the activity comparable to the corresponding homogeneous catalyst.

Reference [1] G. van Koten, P. W. N. M. van Leeuwen, in Catalysis: an Integrated Approach, ed. R. A. van Santen, P. W. N.

M. van Leeuwen, J. A. Moulijn, et al, Elsevier, Amsterdam, 2nd edn., 1999, ch. 6. [2] W. Zhou, D. He. Chem. Commun., 2008, 5839. [3] J. Dean, Analytical Chemistry Handbook. Singapore: McGraw-Hill Book Co., 1995.

OC-2

42

Directed ortho-Borylation of Functionalized Arenes Catalyzed by a Silica–Supported Compact Phosphine–Iridium System

Soichiro Kawamorita, Kenji Yamazaki, Hirohisa Ohmiya and Masaya Sawamura*

Department of Chemistry, Faculty of Science, Hokkaido University Sapporo 060-0810, Japan, E-mail: [email protected]

The metal-catalyzed direct functionalization of aromatic C–H bonds is a straightforward method for carbon–carbon and carbon–heteroatom bond formations. Generally, the activation of the C–H bond is facilitated by efficient generation of a coordinatively unsaturated metal species, where the sparsity of the vacant coordination site is important for high catalytic activity and a broad substrate scope. We have developed Silica-SMAP, a silica-supported, caged, compact phosphine ligand. Due to its constrained mobility, this ligand forms a mono(phosphine)–metal complex selectively despite its extreme compactness.1,2 Accordingly, we envisioned that the supported phosphine would be useful in creating a highly active catalytic environment for C–H bond functionalizations.

Here we present that the Silica-SMAP–Ir system, which was prepared from [Ir(OMe)(cod)]2 and Silica-SMAP, showed high activities and selectivities for the borylation of aromatic C–H bonds with B2(pin)2.3 This system was particularly effective for the directed ortho-borylation of functionalized arenes, showing considerable tolerance toward the steric congestion. Moreover, it was applicable to a broad scope of arenes with different directing groups.

Silica-SMAP–Ir (0.5 mol %)

(pin)B-B(pin)hexane or octane2 eq

25 °C, 2 h, 89%50 °C, 3 h, 87%

50 °C, 3 h, 79%

RDG

H

RDG

BO

O

OMe

O

B(pin)

OMe

O

B(pin)Me

MeNMe2

O

B(pin)100 °C, 6 h, 72%

OMOM

B(pin)70 °C, 2 h, 105%

O

O

B(pin)

50 °C, 2 h, 89%

SO3Me

B(pin)50 °C, 4 h, 75%

B(pin)

Clarylboronate

temp, time, isolated yield

Si

P

OSi OO

O

OSi OO

OSiO2

SiMe3

Silica-SMAP–IrIr OMe

F3C

OMe

O

B(pin)

OMe

Cl25 °C, 4 h, 85%

70 °C, 8 h, 113%

O

B(pin)

NEt2

O

(1) SMAP: silicon-constrained monodentate trialkylphosphine. See: (a) Ochida, A.; Hara, K.; Ito, H.;

Sawamura, M. Org. Lett. 2003, 5, 2671. (b) Ochida, A.; Hamasaka, G.; Yamauchi, Y.; Kawamorita, S.; Oshima, N.; Hara, K.; Ohmiya, H.; Sawamura, M. Organometallics 2008, 27, 5494.

(2) (a) Hamasaka, G.; Ochida, A.; Hara, K.; Sawamura, M. Angew. Chem. Int. Ed. 2007, 46, 5381. (b) Hamasaka, G.; Kawamorita, S.; Ochida, A.; Akiyama, R.; Hara, K.; Fukuoka, A.; Asakura, K.; Chun, W. J.; Ohmiya, H.; Sawamura, M. Organometallics 2008, 27, 6495. (c) Kawamorita, S.; Hamasaka, G.; Ohmiya, H.; Hara, K.; Fukuoka, A.; Sawamura, M. Org. Lett. 2008, 10, 4697.

(3) Kawamorita, S.; Ohmiya, H.; Sawamura, M. J. Am. Chem. Soc. 2009, 131, 5058.

OC-3

43

Catalyst Leaching - an Efficient Tool for Constructing New Catalytic Reactions: Pd and Ni Chalcogenides in Selective

Carbon-Heteroatom Bond Formation

Valentin P. Ananikov, Irina P. Beletskaya

Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect 47, Moscow, 119991, Russia; e-mail: [email protected]

Chemistry Department, Lomonosov Moscow State University Vorob’evy gory, Moscow, 119899, Russia

Recently we have developed a novel approach for size- and shape controlled synthesis of Pd and Ni nanoparticles with organic ligands using simple precursors and convenient reaction conditions.[1] Leaching of metal species from the surface of the nanoparticles to solution was found as a convenient tool to control direction of the chemical transformation and selectivity of the catalytic reactions (Scheme 1).

Cover picture

Eur. J. Inorg. Chem. No 9, 2009

Scheme 1 The process of leaching was monitored in real time with 1D and 2D NMR, and the nature of the metal species was established (i.e. the relationship between path A, B and C). It was shown that catalyst leaching is a powerful tool for generating a new catalytic activity from in situ formed species where the parent bulk particles are inactive. In the developed catalytic system a novel synthetic procedures were successfully implemented to access new types of sulfur and selenium compounds in high yields and to carry out S-S and Se-Se bonds activation in organic molecules.

Acknowledgement. The research was supported by RFBR grants 08-03-11003, 07-03-00851 and Programs No 18, 27 of Russian Academy of Sciences.

References 1. (a) V. P. Ananikov, I. P. Beletskaya, et al. J. Am. Chem. Soc., 2007, 129, 7252; (b) Organometallics, 2007, 26, 740; (c) Chem. Eur. J., 2008, 14, 2420; (e) Eur. J. Org. Chem., 2007, 3431; (d) Eur. J. Inorg. Chem., 2009, 1149.

OC-4

44

Catalytic Activity of Metal Nanoparticles stabilized with Chiral Modular Ligands

Carmen Claver, Aitor Gual, Cyril Godard, Karine Philippota, Bruno Chaudreta, Audrey Denicourt-Nowicki b, Alain Roucoux b and Sergio Castillón

Department de Química Física I Inorgànica, Universitat Rovira iVirigli, Tarragona, Spain, E-mail: [email protected] a CNRS; Laboratoire de Chimie de Coordination, Toulouse, France, b Ecole Nationale

Supérieure de Chimie de Rennes, France.

Metallic nanoparticles (NPs) based on Ru, Rh and Ir were prepared by decomposition of organometallic precursors under H2 pressure in the presence of 1,3-diphosphites derived from carbohydrates as stabilising agents.[1,2] Interestingly, structural modifications of the diphosphite backbone influence the nanoparticle size and dispersion as well as their catalytic activity.

OR3

R2

POR1

OO

O

O OO

R3 R2

O R1

OPO

O

OO

Me

OMe

Me

OMe

Me

OMe

Me

OMe

H2

H2

PP

Figure 1. TEM micrographs and size histograms for M-NPs, and their use as nanocatalysts in the hydrogenation of o,m-methylanisole.

In the hydrogenation of o,m-methylanisole, the Rh-NPs showed higher activity than the corresponding Ru-NPs. The Ir-NPs presented the lowest activity of the series. Hydrogenation of o-methylanisole gave rise to a total selectivity in the cis-product, although the product ee was only up to 6 %. With m-methylanisole up to 73 % cis-selectivity without asymmetric induction was achieved. Finally, the catalytic results showed that they are clearly affected by the substrate, the diphosphite ligand and the metal nanoparticle.

1 A. Gual, M.R. Axet, K. Philippot, B. Chaudret, A. Denicourt-Nowicky, A. Roucoux, S. Castillón, C. Claver, Chem. Commun. 2008, 2759-2761. 2 A. Gual, C. Godard, K. Philippot, B. Chaudret, A. Denicourt-Nowicky, A. Roucoux, S. Castillón, C. Claver, Chemsuschem. Submitted.

OC-5

45


Homogenization of Heterogeneous Catalysts: Stabilization of Metal-Nanoparticles by Soluble Dendritic Architectures and

Applications thereof

Juliane Keilitz,a Sabrina Nowag,a Jean-Daniel Marty,b Christophe Mingotaud,b and Rainer Haag*,a

a) Freie Universität Berlin, Institute for Chemistry and Biochemistry, Takustr. 3, 14195 Berlin, Germany; [email protected];

b) Laboratoire des IMRCP, Université de Toulouse, CNRS UMR 5623, 31062 Toulouse Cedex 09, France

Usually homogeneous catalysts are heterogenized to afford recyclability.[1] The opposite approach, the homogenization of heterogeneous catalysts became more popular in the last decades since metal nanoparticles can be stabilized in solution by small molecules or by soluble polymers keeping them recyclable.[2] The small size of the nanoparticles provides them with unique chemical and physical properties different from the properties of the bulk material or single metal ions.[3]

When it comes to catalytic applications, the problem arises to control the nanoparticles size and to stabilize them against aggregation induced by changes in the pH or ionic strength during catalytic reactions. At the same time a strong adsorption of the stabilizer on the particle has to be prevented in order to keep the surface available for reactants and substrates.

We recently presented the stabilization of gold nanoparticles in soluble dendritic core-multishell architectures with a poly(ethylene imine) (PEI) core.[4] Those core-multishell architectures are composed of a hydrophilic core, a hydrophobic inner shell and a hydrophilic outer shell. For catalytic applications PEI was exchanged by polyglycerol (PG) to avoid strong adsorption on the nanoparticles surface.

Here we present the synthesis and stabilization of metal nanoparticles in soluble dendritic core-multishell architectures, their transfer to organic solvents ranging from polar to unpolar and their application in various hydrogenation reactions. [1] M. Heitbaum, F. Glorius, I. Escher, Angew. Chem. Int. Ed. 2006, 45, 4732-4762; E.D. Park, K.H. Lee, J.S.

Lee, Catalysis Today 2000, 63, 147-157; [2] D. Astruc, F. Lu, J.R. Aranzaes, Angew. Chem. Int. Ed. 2005, 44, 7852-7872; C.C. Tzschucke, C. Markert,

W. Bannwarth, S. Roller, A. Hebel, R. Haag Angew. Chem. Int. Ed. 2002, 41, 3964-4000; [3] G. Schmid, Chem. Rev. 1992, 92, 1709-1727; [4] J. Keilitz, M.R. Radowski, J.-D. Marty, R. Haag, F. Gauffre, C. Mingotaud, Chem. Mater. 2008, 20, 2423-

2425.

OC-6

46


Plasmonics meets Catalysis: A Novel Highly Versatile Remote Sensing Technique to Monitor Catalytic Reactions

Elin M. Larsson, Christoph Langhammer, Igor Zoric, Bengt Kasemo

Department of Applied Physics, Chalmers University of Technology, Gothenburg, Sweden

To understand and improve heterogeneous catalyst systems it is important to be able to monitor the catalyst’s state (e.g. reactant coverage or oxidation state) and to follow the reaction in real time. However, there is still a need of new experimental probes that allow such investigations to be made on the often complex catalyst structures and under real reaction conditions. We report a new method that with a remarkably simple optical trans-mission (or reflection) measurement can sensitively follow catalytic reactions in real time and can be applied to both model catalysts and real supported catalysts at atmospheric pressure. This technique is suitable for use in harsh environments and in a remote sensing set up. The principle is “nanoplasmonic” (localized surface plasmon resonance, LSPR) sensing, which has been intensely investigated for biosensing. The plasmon excitation causes a peak in the optical extinction versus wavelength spectrum. The peak position, λmax, measured in the experiment, is sensitive to surface changes of e.g. catalyst particles in the near (nm) proximity of the plasmonic particle. We show that LSPR sensing can be used to detect coverage changes on Pt clusters, with a sensitivity of less than 0.1 monolayers of oxygen during oxidation of H2 or CO. Additionally, we show that NOx storage and release from BaO (commonly used in NOx storage catalysts) can be monitored using this technique [1]. We predict that nanoplasmonic sensing of catalytic reactions on supported and model catalysts will open up a new field in catalysis research and may provide new sensors e.g. for the automotive industry.

Figure 1A shows the plasmon peak shift, Δλmax (blue curves) and the sample temperature shift (brown/red curves), during the oxidation of H2 (H2+½ O2 →H2O) over Pt clusters. The data is plotted as a function of the relative H2 concentration, α = [H2]/([H2]+[O2]). The most notable feature is the discontinuous step up (down) in Δλmax at αcr = 0.5, corresponding to the well known kinetic phase transition in the H2+O2 reaction, where a sudden transition occurs from an oxygen covered surface at low α to a partially hydrogen covered surface at high α. This example demonstrates that LSPR sensing can detect submonolayer coverage changes (estimated sensitivity <0.1 monolayers of oxygen). Similar results were obtained for CO oxidation over Pt clusters (CO+½ O2→CO2).

Figure 1B shows the plasmon peak shift during 30min NO2 storage in BaO, at seven different concentrations (0, 30, 50, 100, 250, 500 and 1000ppm), and subsequent release by exposure to 2% H2 (at t=38min). The peak shift after 30min storage is quantified in figure 1C.

1. E.M. Larsson et al. Nanoplasmonics meets catalysis. Submitted to Science

OC-7

47

Minor Enantiomer Recycling

Christina Moberg,a* Erica Wingstrand,a Anna Laurell,a Linda Franssona,b and Karl Hultb a KTH School of Chemical Science and Engineering, Organic Chemistry, SE 100 44 Stockholm, Sweden;

b KTH School of Biotechnology, Department of Biochemistry, AlbaNova University Center, SE 106 91 Stockholm, Sweden

A minor enantiomer recycling one-pot procedure employing two reinforcing chiral catalysts has been developed. Scalemic O-acylated cyanohydrins are prepared via chiral Lewis acid-achiral Lewis base catalyzed addition of acetyl cyanide to prochiral aldehydes.1 Continuous regeneration of the achiral starting material is effected via selective enzyme catalyzed hydrolysis of the minor product enantiomer. The thermodynamic driving force for the process consists of the formation of acetic acid, which is deprotonated to acetate under the slightly basic conditions. This recycling process provides O-acylated cyanohydrins in close to perfect enantioselectivities, higher than those obtained under optimal conditions in the direct process, and in high yields.. A combination of a (S,S)-salen Ti Lewis acid and Candida antarctica lipase B provides the products with R absolute configuration, whereas an opposite enantiomer is obtained from the (R,R)-salen Ti complex and Candida rugosa lipase or Candida cylindracea lipase.

R H

O

R CN

O

R CN

O

R CN

O

LB, LA*

R CN

OH

O

O

H2O

OH

O

enzymeHCN

toluene

waterbuffer, pH 8

chemical driving force

apparent reaction

stoichiometry

O-

O

1) a) Lundgren, S.; Wingstrand, E.; Penhoat, M.; Moberg, C. J. Am. Chem. Soc. 2005, 127, 11592-11593; b)

Lundgren, S.; Wingstrand, E.; Moberg, C. Adv. Synth. Catal. 2007, 349, 364-372.

OC-8

48

Mode of Action of Normal and Abnormal Carbene Metal Complexes in Hydrogenation Catalysis

Anneke Krüger, Marion Heckenroth, Claudio Gandolfi, Martin Albrecht

School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland and Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland

In recent years, catalyst development has greatly profited from the discovery of N-heterocyclic carbenes as ligands for transition metals. Typically, such carbene complexes are prepared from imidazolium salts via deprotonation and concerted or subsequent metallation at C2. Upon steric or chemical protection of the C2-postion, or upon activation of the C4-position, abnormal carbene bonding and metallation at C4 can be successfully promoted.1 Recent studies have demonstrated that such abnormal carbene bonding increases the electron density at the metal center substantially, thus facilitating oxidative addition reactions and also reactions in which the metal center needs to be nucleophilic.2

NN2

4 5

M

NN2

4 5M

normal abnormalcarbene

NN

NN

MXnLm

N

N

N

N

MXnLm

2

45

2

4

5

1 2

We have exploited the electronic impact of these abnormal carbene ligands in transition metal-mediated catalysis. Specifically, platinum group metal centers such as rhodium and palladium exert significantly improved catalytic activity in direct hydrogenation and transfer hydrogenation when bound to abnormal rather than normal dicarbene ligands (cf. 1 and 2 in Figure above; MXnLm = RhI2(NCMe)2

+ Pd(NCMe)22+, PdCl2).3 We will present our

mechanistic investigations using combinations of in situ NMR spectroscopy, dynamic light scattering, and poisoning experiments, which allowed the catalytically active species to be identified. Furthermore, evidence will be provided for the decisive influence of the wingtip group R’ in order to promote either heterogeneous or homogeneous ruthenium-mediated activation of H2 at high pressure. 1 M. Albrecht, Chem. Commun. 2008, 3601. 2 P. Mathew, A. Neels, M. Albrecht, J. Am. Chem. Soc. 2008, 130, 13534; M. Heckenroth, E.

Kluser, A. Neels, M. Albrecht, Dalton Trans. 2008, 6242; M. Heckenroth, A. Neels, M. G. Garnier, P. Aebi, A. W. Ehlers, M. Albrecht, Chem. Eur. J. 2009, 15, in press.

3 M. Heckenroth, E. Kluser, A. Neels, M. Albrecht, Angew. Chem. Int. Ed. 2007, 46, 6293; L. Yang, A. Krüger, A. Neels, M. Albrecht, Organometallics 2008, 27, 3161.

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49

Enantioselective CO2 Incorporation to Propargylic Alcohols Catalyzed by Silver Complexes

Tohru Yamada*

Department of Chemistry, Keio University, Yokohama 223-8522 Japan

The catalytic amount of silver acetate with combined use of DBU was found to be an efficient catalyst system for the incorporation reaction of carbon dioxide into various propargylic alcohols to afford the corresponding cyclic carbonates in high-to-excellent chemical yields under mild reaction conditions.1) Their geometry of exo-alkene in all the cyclic carbonates was confirmed to be completely Z form by X-ray crystal structure analysis and NOE experiments. Whereas in an aprotic polar solvent, various tertiary and secondary propargyl alcohols were efficiently converted into the corresponding α,β-unsaturated carbonyl compounds in high yield.2) The isotopic experiment using C18O2 revealed that carbon dioxide mediated the intramolecular rearrangement to an alkyne activated by silver catalyst. The preliminary DFT calculation of the model system also suggested that the silver catalyst would activate C-C triple bond as π-Lewis acid. In the presence of the charge-delocalizable amine such as DBU, it was predicted that the silver catalyst would locate in the anti position of carbonate anion to afford the Z form product. Then the optically active ligand would realize the enantioselective CO2 incorporation reaction to propargylic alcohols. It was found the combined use of silver acetate and the Schiff base ligand derived from 2-pyridinecarboxaldehyde and optically active 1,2-diaminocyclohexane activated bispropargylic alcohols effectively to produce the corresponding cyclic carbonate with Z-form exo-olefin in high yield with good enantioselectivity.

OH

R3R2

R1CO2

O

R3R2

R1

O

O

Ag+

AO

O

O

R3

R2 R1

O

O

O

R3

R2

R1

O C OR3 R2

R1O

BAg+

DBU

[3,3]-sigmatropic rearrangement

in toluene

in DMF

Carbonate

Enone

path A

path B

N

NCH3

HO

CH3 CH3

CH3

O

O

Ag

Ph Ph

HO CH3

Ph OO

O

H3CPh

*

5 mol% AgOAc6 mol% LigandCO2

8 hr89% yield73% ee

CHCl3, RT+

(1.0 MPa)

N N

NN

Ligand :

References 1) Yamada, W.; Sugawara, Y.; Cheng, H.-M.; Ikeno, T. Yamada, T.; Eur. J. Org. Chem. 2007, 2604-2607. 2) Sugawara, Y.; Yamada, W. Yoshida, S.; Yamada, T. J. Am. Chem. Soc. 2007, 129, 12902-12903.

OC-10

50

On Direct Iron-Catalyzed Cross-Coupling Reactions

Axel Jacobi von Wangelin*

Department of Chemistry, University of Cologne, Germany

Transition metal-catalyzed cross-coupling reactions have matured to an indispensable class of carbon-carbon bond forming reactions for organic synthesis. The high costs associated with the use (and removal) of palladium and nickel catalysts as well as toxicological aspects have constricted a more general use of such protocols in large scale productions. However, the recent developments of iron-catalyzed cross-coupling procedures have addressed these sustainability issues. The effectiveness of such coupling reactions of organohalides with nucleophilic organomagnesium species has proven effective in the synthesis of building blocks and natural products.[1] In view of industrial processes however, the employment of highly sensitive organomagnesium halides still imposes stringent and cost-intensive safety arrangements on the overall process.

We wish to report on a new, operationally simple protocol for the direct iron-catalyzed cross-coupling reaction of aryl halides with alkyl halides to give substituted arenes in a one-pot procedure under mild conditions. The underlying domino reaction involves the iron-catalyzed formation of small amounts of the prerequisite Grignard species and its immediate consumption in an iron-catalyzed cross-coupling reaction with high selectivity. The overall process utilizes a single cheap pre-catalyst (FeCl3) and obviates the need for the handling of large quantities of hazardous organomagnesium halides.[2]

XR

YR'+

5 mol% FeCl31.1 equ. Mg, 1.1 equ. TMEDA

THF, 0 °C, 2 h RR'

N

OMe

74 %79 % 68 % 58 %

Me2N

75 %

CO2Et

65 %

New mechanistic details and the unprecedented concept of domino iron catalysis will be discussed. Recent extensions of such direct cross-coupling methodology include a novel synthesis of styrenes and biaryl formations without resorting to the handling of pre-formed organometallic species.[3] [1] W. M. Czaplik, M. Mayer, J. Cvengroš, A. Jacobi von Wangelin, ChemSusChem 2009, in press. [2] W. M. Czaplik, M. Mayer, A. Jacobi von Wangelin, Angew. Chem. Int Ed. 2009, 48, 607. [3] W. M. Czaplik, M. Mayer, A. Jacobi von Wangelin, submitted.

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Synthesis of chiral 1,3-diols with two stereogenic centres by using organo- and biocatalysis

Katrin Baer[a] Marina Kraußer[a], Edyta Burda[a], Werner Hummel[b] and Harald Gröger[a]

[a] Department of Chemistry and Pharmacy, Friedrich-Alexander-University of Erlangen-Nuremberg, Henkestr. 42, 91054 Erlangen, Germany; e-mail: [email protected]

[b] Institute of Molecular Enzyme Technology at the Heinrich-Heine University of Düsseldorf, Research Centre Jülich, Stetternicher Forst, 52426 Jülich, Germany

Chiral 1,3-diols with two stereogenic centers are important building blocks for the synthesis of pharmaceutically relevant compounds and natural products.[1] A multitude of methods for the stereoselective synthesis of these compounds has been developed.[2] However, the number of syntheses which offer an access to all four type of stereoisomers is still limited.

In this contribution we describe the stereoselective and sequential formation of the two stereogenic centers of 1,3-diols 4. This two-step process is based on an initial enantioselective organocatalytic aldol reaction according to a modified literature protocol[3] starting from acetone and aromatic aldehydes 1. Subsequent biocatalytic reduction of the formed β-hydroxy ketones 3 using alcohol dehydrogenases gave the desired 1,3-diols of type 4 (Scheme 1).

Scheme 1. Sequential formation of 1,3-diols

The first stereogenic center was formed with enantioselectivities of about 83% ee under solvent free conditions by means of a proline-derived organocatalyst. In the second step two different alcohol dehydrogenases were used to form the second stereogenic center in a highly stereoselective fashion. All stereoisomers of 1,3-diols 4 have been obtained in excellent enantiomeric excess of >99% ee. Thus, such a combination of aldol reaction and biocatalytic reduction represents an attractive access to all four different stereoisomers of 1,3-diols with high diastereo- and enantioselectivities. In addition, the reaction mixtures resulting from the organocatalytic reaction turned out to be compatible with the following enzymatic reduction. Thus, there is no need for workup and isolation steps of the aldol reaction.

[1] A. Kleemann, J. Engels, B. Kutscher, D. Reichert, Pharmaceutical Substances:

Syntheses, Patents, Applications, 4th ed., Thieme-Verlag, Stuttgart, 2001. [2] S. E. Bode, M. Wolberg, M. Müller, Synthesis 2006, 4, 557-588 [3] V. Maya, M. Raj, V. K. Singh, Organic Letters 2007, 2593-2595

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Selective methane coupling to ethane and hydrogen catalyzed by grafted Tantalum or Tungsten hydride

Kai C. Szeto, Sébastien Norsic, Nicolas Merle, Mostafa Taoufik, Jean Thivolle-Cazat, Jean-Marie Basset

Laboratoire de Chimie Organométallique de Surface, UMR 5265 CNRS CPE-Lyon, 43 Bd du 11 Novembre 1918, 69616 Villeurbanne, France

Current approach to design catalysts is addressed to surface organometallic chemistry. The catalyst is prepared by grafting a reactive organometallic complex on conventional support materials with high surface area and functional groups that can react with the complex. Hence, a heterogeneous and well-defined single site catalyst can be obtained after an activation process. Based on this concept, exceptional selective catalysts for coupling of methane to ethane and hydrogen without an oxidation agent have been developed.1 The catalysts are based on Ta-H or W-H grafted on silica or alumina and the reaction is carried out in a fixed-bed reactor at 350 °C and 50 bar. The conversion remains constant at the thermodynamic equilibrium, as shown in Figure 1. Moreover, the converted product is hydrogen and ethane in virtually equivalent quantities and trace amount of propane (≈ 0.3%).

0 20 40 60 800.00

0.05

0.10

0.15

0.20

20 40 60 800

20

40

60

80

100b)

Con

vers

ion

(%)

t (h)

a)

Hydrogen Ethane

Selectivity (%)

Figure 1. Conversion (part a) and selectivity (part b) of methane coupling catalyzed by W-H/Al2O3.

Spectroscopic investigations reveal the presence of methyl, carbene and carbyne species attached to the metal (Ta or W) in an activated catalyst exposed to methane. The mechanism of the reaction is purposed in Figure 2.

Figure 2. Purposed mechanism for methane coupling

Upgrading methane to added value products is attractive for many reasons.2 The presented reaction operates at significantly lower temperature than commercial processes for synthesis gas production. Moreover, coupling of methane is CO2 free and produces the highly demanded hydrogen and ethane which is an important starting material for petrochemical processes.

1 Soulivong, D.; Norsic, S.; Taoufik, M.; Copéret, C.; Thivolle-Cazat, J.; Chakka, S.; Basset, J.-M. J. Am. Chem. Soc. 2008, 130, 5044.

2 Bergman, R. G. Nature 2007, 446, 391.

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Direct Dehydrogenative Amide Synthesis from Alcohols and Amines Catalyzed by γ-Alumina Supported Silver Cluster

Ken-ichi Shimizu, Keiichiro Ohshima, and Atsushi Satsuma

Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-860, Japan

Direct amidation from alcohols and amines driven by H2 removal, reported by Milstein et al.,[1a] is of great interest as an ideal method for amide synthesis. To date, only two homogeneous Ru catalysts with molecularly designed cooperative ligands were reported.[1] However, these expensive catalysts do not tolerate secondary amines and have difficulty in catalyst/product separation and necessity of special handling of metal complexes. Very recently, we reported that γ-alumina-supported silver cluster (Ag/Al2O3)[2] acts as heterogeneous catalyst for the oxidant-free dehydrogenation of alcohols and one-pot C-C cross-coupling reaction from secondary and primary alcohols. Here we report the first example of heterogeneously catalyzed reaction of alcohols with amines to form amides and H2 using the easily prepared and inexpensive heterogeneous catalyst, Ag/Al2O3.

Catalysts were prepared by impregnating oxides with an aqueous solution of silver nitrate followed by evaporation to dryness, calcination, and H2-reduction. The reaction of 4-fluorobenzylalcohol 1 and morpholin 2 was chosen as test reaction in order to optimize all different parameters. Under the optimized condition (alcohol/amine ratio= 1/2, 4 mol% Ag/Al2O3, 20 mol% Cs2CO3, 130˚C), yield of the corresponding amide 3 was 91%. This is the first successful PGM-free catalyst for the title reaction as well as the first example of direct amide formation from secondary amine and alcohol. This method tolerates various primary alcohols, including aliphatic primary alcohols. The silver cluster with smaller particle size, especially below 2 nm, gives higher TOF per surface Ag sites. Basic (CeO2 and MgO) and acidic (SiO2, SiO2-Al2O3) supports resulted in lower activity than Al2O3 having both acidic and basic surface OH groups, indicating important roles of acidic and basic sites of the support. Basic sites at the silver-support interface deprotonate alcohol to give alkoxide intermediate on Al2O3, and protonic OH groups adjacent to silver sites facilitate the removal of hydride species from the silver sites to regenerate a coordinatively unsaturated site on silver cluster.[2a] Coordinatively unsatulated Ag atom is required for the C-H cleavage of alkoxide or hemiaminal species (Scheme 1). Our findings provide a new synthetic strategy of C-H activation catalyst using non-PGM material with inorganic cooperative ligands, i.e. OHδ+/OHδ- groups on alumina.

OH+ toluene(2 mL)

130 oC, 24 h

Ag/Al2O3(4mol%)Cs2CO3(20 mol%)

1 2 3F

OHN N

F

O

O1.0 mmol 2.0 mmol Yield=91%

OHR1

−O

R1 NR2

Agn

O

R1 NR2

H2 H+

+ H+ on Al2O3

R2-NHR3

Agn O−

R1

H H

Agn H-

δ− δ+

Agn

H2 H+

Agn H-

base

+ H+ on Al2O3

R3 R3

Agn

Hδ−

Scheme 1..

[1] a) C. Gunanathan, Y. Ben-David, D. Milstein, Science 2007, 317, 790; b) L. U. Nordstrom, H. Vogt, R. Madsen, J. Am. Chem. Soc. 2008, 130, 17672-17673. [2] a) K. Shimizu, K. Sugino, A. Satsuma, Chem. Eur. J. 2009, 15, 2341; b) K. Shimizu, R. Sato, A. Satsuma, Angew. Chem. Int. Ed., in press.

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Hybrid Catalysis with Nanostructured POSS Metal derivatives

Hendrikus C. L. Abbenhuis,* Nollaig Ni Bhriain, Gijsbert Gerritsen, Pieter C. M. M. Magusin, Lei Zhang, Rutger A. van Santen and Dieter Vogt

Eindhoven University of Technology, Homogeneous Catalysis and Coordination Chemistry, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; hybridcatalysis.com

We have pioneered the development of a new chemical technology for catalysis. This technology bridges the property space between hydrocarbon-ligated metal complexes and oxidic supported catalysts. It imparts new or improved properties to catalytic materials achieving uncannily precise molecular architectures. Catalysts are derived from chemicals known as polyhedral oligomeric silsesquioxanes (POSS) rendering silanolate metal derivatives. POSS catalysts have unique features:

•The chemical composition of the support is a hybrid, intermediate (RSiO1.5) between that of silica (SiO2) and silicones (R2SiO). The support is electron-withdrawing and increases Lewis acidic catalyst activity.

•POSS catalysts can contain one or more covalently bonded reactive functionalities suitable for polymerization, grafting, surface bonding, or other transformations covering the generation of precise catalytic materials and catalyst supports.

•POSS catalysts are physically large and range approximately 1-3nm in size. They can be molecularly enlarged (POSS building block chemistry) to cover applications from homogeneous catalysis via membrane catalyst retention to truly heterogeneous catalysis, either in gas or liquid phase application.

Presented are newly developed catalysts for alkene metathesis, oligomerization, polymerization and epoxidation.

L. Zhang, H.C.L. Abbenhuis, N. Ni Bhriain, P.C.M.M. Magusin P.C.M.M. et al., Chem. Eur. J., 2007, 13, 1210-1221.; R. W. J. M. Hanssen, R. A. van Santen, H. C. L. Abbenhuis, Eur. J. Inorg. Chem., 2004, 675-683.; J.I. van der Vlugt, J. Ackerstaff, T.W. Dijkstra, A.M. Mills, H. Kooijman, A.L. Spek, A. Meetsma, H.C.L. Abbenhuis, D. Vogt; Adv. Synt. Catal.; 2004, 346(4), 399-412.; M. D. Skowronska-Ptaskinska, M. L. W. Vorstenbosch, R. A. Van Santen, H. C. L. Abbenhuis, Angew. Chem. Int. Ed. 2002, 41, 637-639.; H. C. L. Abbenhuis, Chem. Eur. J. 2000, 6, 25-32.

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Sub-nanometric Pd particles stabilized inside highly cross-linked polymeric matrices

E. Groppo, W. Liu, O. Zavorotynska, G. Agostini, C. Lamberti, G. Spoto, S. Bordiga and A. Zecchina

Department of Inorganic, Physical and Materials Chemistry, NIS center of excellence, and INSTM Centro di Riferimento, University of Torino, via P. Giuria 7, I-10125 Torino, Italy

Pd nanoparticles are attracting increasing interest because of their unique properties and potential applicability in many scientific fields, including microelectronics, chemical sensing, data storage, and especially catalysis, where they are employed for hydrogenation and dehydrogenation reactions, oxidation reactions, and for a large number of carbon–carbon bond forming reactions such as Heck or Suzuki coupling. The formation of nanoclusters necessarily requires stabilization to prevent aggregation, which would eradicate most of their desirable advantages compared with bulk material. Recently, a great number of stabilizing methods have been developed for controlled formation of Pd nanoclusters.

An innovative approach is the in situ formation of Pd nanoparticles inside highly cross-linked polymers. In this study, two kinds of DVB cross-linked polymers, a poly(4-vinylpyridine-co-ethylvinylbenzene) (P4VP) and a poly(4-ethylstyrene-co-divinylbenzene) (PS) are successfully used as porous supports for Pd nanoparticles with different size, obtained by in-situ reduction of Pd(OAc)2 precursor. The particle size distribution, accessible surface area, type of exposed sites and optical properties of the Pd nanoparticles are carefully characterized by a large variety of techniques, such as TEM microscopy and in situ EXAFS, FTIR of adsorbed CO, and UV-Vis spectroscopies. We demonstrate that the nature of the polymeric matrix strongly influences the properties of Pd nanoparticles, both in terms of particle size distribution and of electronic properties.

In particular, TEM and EXAFS demonstrate that much smaller Pd nanoparticles are formed in P4VP with respect to PS. These sub-nanometer particles feel a different electronic environment with respect to those present in the PS matrix, due to the proximity of the pyridine units, acting as electron donors. This is evidenced indirectly by FTIR spectroscopy of adsorbed CO and UV-Vis spectroscopy and directly by EXAFS, revealing the presence of nitrogen neighbours close to the sub-nanometer Pd particles in P4VP. Preliminary catalytic results on the two systems will be also presented.

2100 2000 1900 1800 1700

Abs

orba

nce

(a.u

.)

Wavenumber(cm-1)

0.2

Pd/P4VP Pd/PS Pd/P4VP

Pd/PS

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Selective localisation of Pt nanoparticles in the pores or/and walls of a mesostructured silica matrix via the control of

hydrophobic/hydrophilic interactions

Malika Boualleg,1 Jean-Marie Basset,1 Jean-Pierre Candy,1 Pierre Delichere,2 Katrin Pelzer,3 Laurent Veyre,1 Chloé Thieuleux1*

1 Université de Lyon, Institut de Chimie de Lyon, UMR C2P2 - CNRS - Université Lyon 1- ESCPE Lyon, Equipe Chimie Organométallique de Surface 43, Bd du 11 Novembre 1918 F-69616 Villeurbanne, France.

2 Université de Lyon, Institut de Chimie de Lyon, UMR 5256 CNRS-Université de Lyon 1, Institut de Recherches sur la Catalyse et l’Environnement de Lyon (IRCELyon) 2 avenue A. Einstein F-69616

Villeurbanne, France. 3 Fritz-Haber-Institutes of the Max Planck Society, Department for Inorganic Chemistry, Faradayweg 4-6, 14195 Berlin, Germany.

*[email protected]

New pathways leading to smart materials have been recently developed. But so far, the specific incorporation by design of bulky objects inside materials is still a challenge. That is the reason why we have developed an original methodology leading to the selective and regular localisation of small Pt nanoparticles in the pores1, in the walls, or both in the pores and in the walls of mesostructured silica matrixes. These materials were obtained by i) the control of the hydrophilic/hydrophobic character of Pt colloids and ii) the growth of mesostructured silica around these colloids. The hydrophilicity/hydrophobicity of the Pt nanoparticles was found to be the key factor for controlling their selective localisation in the final material.

Moreover, the regular distribution of the nanoparticles and their selective localisation increased drastically their stability and their catalytic performances which were found to be superior to those of classical catalysts, particularly when nanoparticles were located in the walls of the inorganic matrix. References: 1. Boualleg, M., Basset, J.M., Candy, J. P., Delichere, P., Pelzer, K., Veyre, L. & Thieuleux. C., Chem.

Mater. 21, 775-777 (2009).

heptane phase

heptane phase

water phase

water phase

Hydrophobic Pt nanoparticles

Material containing Pt NPs in its pores

Material containing Pt NPs in its walls Hydrophilic Pt nanoparticles

Material containing Pt NPs both in

its pores and walls

)

d)c)

7 nm

e)

7 nm

e))

7 nm

e)

7 nm

50 nm

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Extraordinary catalytic performance of dendritic triphenyl-phosphines (Dendriphos) in Suzuki-Miyaura cross-coupling

Robertus J.M. Klein Gebbink, Dennis J.M. Snelders, Gerard van Koten

Chemical Biology & Organic Chemistry, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands

Site-isolation is one of the general aspects in bio-catalysis and heterogeneous catalysis to account for high and selective activity of a catalytic site. The microenvironment created by, e.g., a protein envelope or a zeolite cage can result in catalytic sites with a low coordination number or a chiral metal center and in addition can prevent deleterious side-reactions like, e.g., dimerization. In homogeneous catalysis site-isolation is more difficult to accomplish and the use of macromolecular scaffolds is often required. In this respect the site-isolation of a mono-metallic active site can be accomplished through the use of a dendritic supporting material [1].

Here, we report on a detailed study of the extraordinary catalytic activity of dendritic triphenylphosphine ligands of the Dendriphos type [2]. In combination with a Pd-source, the activity of these ligands in Suzuki-Miyaura cross-coupling reactions increases with increasing dendrimer generation and leads to very high activities with aryl bromides and very good activities with aryl chlorides [3].

Figure 1. Structure of a first generation Dendriphos ligand.

Detailed investigations show that Dendriphos ligands are relatively electron-poor phosphines, which does not account for their reactivity. Further kinetic and structure-activity relation studies point out that indeed the size of the Dendriphosligands leads to high catalytic activity, ultimately leading to mono-ligated Pd-species, which are held responsible for catalysis [4]. These studies will be discussed along with the substrate scope of cross-coupling reactions catalyzed by Dendriphos systems. [1] For selected reviews, see: a) L.J. Twyman, A.S.H. King, I.K. Martin, Chem. Soc. Rev. 2002, 31, 69-82; b)

R. van Heerbeek, P.C.J. Kamer, P.W.N.M. van Leeuwen, J.N.H. Reek, Chem. Rev. 2002, 102, 3717–3756; c) A. Berger, R.J.M. Klein Gebbink, G. van Koten, Top. Organomet. Chem. 2006, 20, 1–38.

[2] D.J.M. Snelders, R. Kreiter, J.F. Firet, G. van Koten, R.J.M. Klein Gebbink, Adv. Synth. Catal. 2008, 350, 262-266.

[3] D.J.M. Snelders, G. van Koten, R.J.M. Klein Gebbink, manuscript in preparation. [4] D.J.M. Snelders, G. van Koten, R.J.M. Klein Gebbink, manuscript in preparation.

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Group 10 PCP Pincer Complexes as Models for Catalytic Alcohol Carboxylation

Juan Cámpora*,1, Luís M. Martínez-Prieto,1 Cristobal Melero,1 Pilar Palma, Eleuterio Álvarez,1 Concepción Real.2

1. Instituto de Investigaciones Químicas, CSIC-Universidad de Sevilla. C/ Américo Vespucio, 49, 41092, Sevilla, Spain.

2. Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla. C/ Américo Vespucio, 49, 41092, Sevilla, Spain.

Alkyl carbonates are important intermediates for the chemical industry, where they are use as starting materials for polymer synthesis (polycarbonates), solvents and in the formulation of electrolytes for lithium batteries. Large quantities of alkyl carbonates are synthesized from phosgene, a corrosive and highly toxic gas, which should be avoided. However, these could be made in a very clean and direct manner from alcohols and CO2 (Eq. 1). Using carbon dioxide as starting material would be an example of industrial shift towards greener and more sustainable technologies. Unfortunately, in contrast with water, which spontaneously forms carbonic acid, alcohols do not react directly with CO2. In addition, the free energy balance of Eq 1 is weakly favorable at the ambient conditions (1 atm, 20 ºC), and turns unfavorable at higher temperatures.

2 R-OH + CO2 + H2OO O RR

O

(1)Keq

ΔHº - -5 Kcal•mol-1 Alcohol carboxylation is catalyzed either by heterogeneous and homogeneous catalysts. Although the reaction thermodynamics dictate that high conversions would be achievable only at low temperatures, catalysts require in general harsh reaction conditions and therefore yields are usually very low. In this contribution, we analyze the mechanism of the reaction mechanism using group 10 (Ni, Pd) complexes stabilized by robust PCP “pincer” ligands. The strong chelating properties of these ligands prevent the association of the involved hydroxo, alkoxo and carbonato complexes, favoring isolated species comparable to those that would be found in heterogenous catalysts. For example, we have observed the formal insertion of CO2 into metal hydroxo and alkoxo complexes to afford bicarbonato (M-OCOOR) and alkylcarbonato (M-OCOOR) derivatives, respectively (Scheme 1). This process is reversible and decarboxylation to afford binuclear carbonates has been observed both in solution and in the solid state. DSC mesurements provide similar values of ca. -33 Kcal·mol-1 for this process. Interestingly, alcohols split the M-OCOO- linkage of metal carbonates producing metal alkylcarbonates (Ec. 2), but as shown in the Scheme, these are reluctant to undergo the same process, which would give rise to the sought alkyl carbonate, regenerating the metal hydroxide. We analyze the causes of this failure.

[M]-OH + CO2 [M]-OCOOHCO2 - 1/2 CO2

- 1/2 H2O[M]-OCOO-[M]

[M]-OCOO-[M]ROH

[M]-OCOO-R + [M]-OCOOH

ROH

X

R-OCOO-R + [M]-OCOOH

M

P

P iPriPr

iPriPr

[M]— =

M = Ni, Pd

Scheme 1

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Development of Chiral Wide Bite-Angle Diphosphine Ligands

C. Czauderna, A.M.Z. Slawin and P.C.J. Kamer*

School of Chemistry, University of St. Andrews, St Andrews, Fife, KY16 9ST e-mail: [email protected]; *e-mail: [email protected]

The reactivity of organo-transition metal complexes in homogeneous catalysis is determined by the environment created by the coordinated ligands. Bite angles of 100 to110° were found to have a significant impact on the rate of various transition metal catalysed reactions.[1]

Our research aims the development of a new type of ligands which combines the concept of the wide bite angle and chirality. Promising candidates are ligands based on the highly flexible diphenylether (DPE) backbone.[2] Based on DPEphos (1) we have synthesised new chelating ligands of which two feature C2 symmetry in the wide bite angle backbone.

OPPh2 PPh2

O OR

O

R

O

R = ethylR = (S)-1- methylpropylR = (S)-1-(4-isobutylphenyl)ethyl

234

OPPh2 PPh2

1

Figure 1 DPE backbone modifications.

Apart from the synthesis, the coordination chemistry of the new ligands was investigated. Their selectivity in homogeneous catalysed reactions, as e.g palladium catalysed allylic substitution, was explored as well. [1] Kamer, P. C. J., van Leeuwen, P. W. N. M., Reek, J. N. H., Acc. Chem. Res. 2001, 34, 895-904. [2] Kranenburg, M., Kamer, P. C. J., Van Leeuwen, P. W. N. M., European Journal of Inorganic

Chemistry 1998, 155-157.

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Gold and Platinum-Catalyzed Intramolecular Cyclization of Alkynes: Synthesis of Pyrrolo-Azepinone derivatives

Marina Gruit, Dirk Michalik, Annegret Tillack and Matthias Beller*

*Leibniz-Institut für Katalyse e.V. An der Universität, Rostock

Our work concerns the application of catalytic reactions for the synthesis of new pharmacologically interesting compounds.1 Recently, we have been interested in the synthesis of novel pyrrolo-azepinone analogues.2 These seven-membered rings are present in a wide number of natural and synthetic products such as Hymenialdisine, Stevensine, Latonduine and Paullones. Aziridines own properties as kinase inhibitors and therefore are promising therapeutic molecules for treatment of a number of diseases including cancer.3

In the last years, intramolecular cyclization reactions of pyrroles or indoles with alkynes catalyzed by transition-metal have been reported.4

We have synthesized, in only two steps, novel pyrrolo-azepinone analogues by a Sonogashira reaction followed by a AuIII or PtIV-catalyzed intramolecular cyclization reaction.

NN

ON

N

ON

N

O

R

H2PtCl6x6H2O

or AuCl3(5 mol%)

PdCl2(PPh3)2

CuI, THF/TEA60 °C, 20 h

R-X1 2 3

R

NN

O

R

4

We varied different halogenated substrates and obtained a N,1-dimethyl-N-(3-phenylprop-2-ynyl)-1H-pyrrole-2-carboxamide 2 family with a yield up to 90%. The intramolecular cyclization reaction gives two compounds 3 and 4 with different ratios, according to catalyst and reaction conditions used. Pyrrolo[2,3-c]azepin-8-one 4 has been obtained as the major product (up to 76% yield) with H2PtCl6 catalyst.

1 a) Schwarz, N.; Pews-Davtyan, A.; Michalik, D.; Alex, K.; Tillack, A.; Diaz, J. L.; Beller, M.; Eur. J. Org. Chem., 2008, 32, 5425–5435; b) Alex, K.; Tillack, A.; Schwarz, N.; Beller, M.; Angew. Chem. Int. Ed., 2008, 47, 2304–2307. 2 a) Mangu, N.; Kaiser, H. M.; Kar, A.; Spannenberg, A.; Beller, M.; Tse, M. K.; Tetrahedron, 2008, 64, 7171–7177; b) Kaiser, H. M.; Zenz, I.; Lo, W. F.; Spannenberg, A.; Schröder, K.; Jiao, H.; Gördes, D.; Beller, M.;. Tse, M. K; J. Org. Chem., 2007, 72, 8847–8858. 3 Meijer, L.; Thunnissen, A. M.; White, A. W.; Garnier, M.; Nikolic, M.; Tsai, L. H.; Walter, J.; Cleverley, K. E.; Salinas, P. C.; Wu, Y. Z.; Biernat, J.; Mandelkow, E. M.; Kim, S. H.; Pettit, G. R.; Chem. Biol., 2000, 7, 51–63. 4 a) Ferrer, C.; Amijs, C. H. M.; Echavarren, A. M.; Chem. Eur. J., 2007, 13, 1358–1373; b) England, D. B.; Padwa, A.; Org. Lett., 2008, 10, 3631–3634; b) Putey, A.; Joucla, L.; Picot, L.; Besson, T.; Joseph, B.; Tetrahedron, 2007, 63, 867–879.

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The modulation of diastereo- and enantioselectivity by immobilization of chiral catalysts

José M. Fraile, José I. García, Clara I. Herrerías, Beatriz López-Sánchez, José A. Mayoral, Ignacio Pérez, Elisabet Pires and Marta Roldán

Departamento de Química Orgánica, Instituto de Ciencia de Materiales de Aragón and Instituto Universitario de Catálisis Homogénea, Facultad de Ciencias, Universidad de Zaragoza-C.S.I.C., 50009 Zaragoza, Spain

Support is usually considered as a necessary evil when a chiral homogeneous catalyst is immobilized, and most of immobilization methods try to place the catalyst far away from the support, in an environment as similar as possible to the homogeneous conditions. However, when bis(oxazoline)-copper complexes are immobilized on laponite (or other clays), the flat surface of the support shows an important effect of on the diastereo- and enantioselectivity of different reactions, namely cyclopropanation,1 carbene insertion into C-H bonds,2 and Mukaiyama aldol reaction3 (Figure 1).

Figure 1. Products distribution of three different enantioselective reactions in homogeneous and heterogeneous phase (laponite supported catalysts): in blue trans (cyclopropanation) or syn isomers (enantiomers are represented by different tones), and in orange cis or anti isomers.

The effect can be either an improvement of both types of selectivity in the case of the insertion reaction, from 51 to 73% overall selectivity for the major syn isomer, or even a complete reversal of both selectivities in the case of cyclopropanation, leading in heterogeneous phase to a major cis isomer of opposite absolute configuration to that of the major trans isomer obtained in solution with much better overall selectivity. Probably the best result to date is that obtained in Mukaiyama aldol reaction. From low diastereoselectivity for syn isomers and nearly zero enantioselectivity in solution, an excellent enantioselectivity of anti isomer is obtained with the heterogeneous catalyst, even allowing the determination of both relative and absolute configurations of the major product. The effects of the support are only obtained with clays and are highly dependent on the chiral ligand and the structure of the reagents.

It can be concluded from those results that the support is not necessarily negative in an immobilized catalyst and heterogeneous and homogeneous chiral catalysts can be complementary when different isomers are obtained in the same enantioselective reaction. 1. J. I. García, B. López-Sánchez, J. A. Mayoral, E. Pires, I. Villalba, J. Catal. 2008, 258, 378. 2. J. M. Fraile, J. I. García, J. A. Mayoral, M. Roldán, Org. Lett. 2007, 9, 731. 3. M. J. Fabra, J. M. Fraile, C. I. Herrerías, F. J. Lahoz, J. A. Mayoral, I. Pérez,, Chem. Commun. 2008, 5402. 4. J. M. Fraile, J. I. García, C. I. Herrerías, J. A. Mayoral, E. Pires, Chem. Soc. Rev. 2009, 38, 695.

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Palladium nanoparticles in ionic liquids: homogeneous versus heterogeneous catalytic behaviour

Montserrat Gómez,* Jérôme Durand, Fernando Fernández, Susanna Jansat, Isabelle Favier and Emmanuelle Teuma

Université Paul Sabatier, Laboratoire Hétérochimie Fondamentale et Appliquée UMR CNRS 5069, 118 route de Narbonne, 31062 Toulouse, France. [email protected]

The design of synthetic strategies involving multi-step processes in one-pot procedure is a key challenge for fine chemical industry, in order to achieve ecologically and economically favourable production, taking into account the costs, solvent toxicity and materials purification [1]. For metal-catalyzed processes, the use of a single catalyst for different kind of reactions is especially attractive. As known, metallic nanoparticles (NP) used as catalytic precursors in wet medium can behave as reservoir of molecular species and also can give a surface-like reactivity, depending on the reaction conditions [2]. This “dual” catalytic behaviour shows an enormous potential in complex transformations in order to economize purification steps. This approach becomes notably appropriated in ionic liquid (IL) medium due to the enhanced stability of the nanoclusters [3].

In this communication, the use of preformed PdNP in ionic liquids as catalytic precursors for C-C bond formation (Suzuki and Heck couplings) and hydrogenation processes will be discussed, mainly concerning the nature of the palladium active species involved [4]. These results have led us to the application of IL-stabilized PdNP in sequential Heck/hydrogenation processes, under base-free conditions allowing the regeneration of nanoparticles after the coupling step [5].

R-X

R'R'

R

H2

R'

R

1st

2nd

References: [1] J.-C. Wasilke, S. J. Obrey, R. T. Baker and G. C. Bazan, Chem. Rev., 2005, 105, 1001. [2] For a recent review, see: J. Durand, E. Teuma and M. Gómez, Eur. J. Inorg. Chem., 2008, 23, 3577. [3] (a) J. Dupont, R. F. de Souza and P. A. Z. Suarez, Chem. Rev., 2002, 102, 3667. (b) P. Wassersheid and W. Keim, Angew. Chem. Int. Ed., 2000, 39, 3772. (c) H. Olivier-Bourbigou and L. Magna, J. Mol. Catal. A: Chemical, 2002, 182-183, 419. [4] (a) J. Durand, E. Teuma, F. Malbosc, Y. Kihn and M. Gómez, Catal. Commun., 2008, 9, 273. (b) F. Fernández, B. Cordero, J. Durand, G. Muller, F. Malbosc, Y. Kihn, E. Teuma and M. Gómez, Dalton Trans., 2007, 5572. [5] S. Jansat, J. Durand, I. Favier, F. Malbosc, C. Pradel, E. Teuma and M. Gómez, submitted.

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Supported Ionic Liquid Phase (SILP) Catalysts – Advanced Materials for Process Intensification and Improved Screening in

Homogeneous Catalysis

Marco Haumann, Michael Jakuttis, Sebastian Werner, Peter Wasserscheid

Lehrstuhl für Chemische Reaktionstechnik, Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany

Supported Ionic Liquid Phase (SILP) catalysts are new materials consisting of an ionic liquid, a metal catalyst and a porous support.[1] The catalyst is dissolved in the ionic liquid which itself is dispersed as a thin film on the inorganic support. This application combines both the advantages of homogeneous and heterogeneous catalysis and thus bridges the gap between traditional homogeneous and heterogeneous catalysis.[2] Especially continuous, gas-phase reactions like hydroformylation or water gas shift reaction are highly suited for this novel and innovative technology.

65 70 75 80 850.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

TOF

Temperature

Time / h

TOF

/ h-1

110

120

130

140

150

160

Temperature / °C

Left: schematic representation of SILP catalytic materials. Right: Steady-state kinetic studies of homogeneous hydroformylation Rh-SILP catalysts.

Preliminary spectroscopic studies in the hydroformylation reaction indicated that the catalyst complex is truly of homogeneous nature in the ionic liquid film and that no interactions occur between the complex and the support. Due to the fact that the homogeneous catalyst operates under steady state conditions, in strong contrast to batch screening experiments, it is possible to determine kinetic parameters in a fast and reliable manner. In automated reactor setups it was possible to determine activation energy, reaction orders as well as reproducibility and stability parameters for a single catalyst within less than 24 h. We therefore anticipate the SILP concept to be highly attractive for future catalyst screening processes.

References: [1] Riisager, A.; Fehrmann, R.; Flicker, S.; van Hal, R.; Haumann, M.; Wasserscheid, P. Angew. Chem. Int. Ed.

2005, 44, 185. [2] Riisager, A.; Fehrmann, R.; Haumann, M.; Wasserscheid, P. Eur. J. Inorg. Chem. 2006, 695.

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NMR-Spectroscopy as a tool for Investigation of Ionic Liqiuds properties

Peter Steffen Schulz, Karola Schneiders, Peter Wasserscheid

Lehrstuhl für Chemische Reaktionstechnik, Friedrich-Alexander-Universität, Erlangen-Nürnberg e-mail: [email protected]

Physical properties of Ionic Liquids, such as ion pairing, can have great influence on the selectivity in chemical reactions. Aside from structural analysis, NMR-Spectroscopy offers a lot of experiments, which helps to get a better understanding in Ionic Liquids´ physical properties.

For the hydrogenation of prochiral keto-functionalized imidazolium IL (1) a strong dependency of chirality transfer from anion to cation and ion pairing effects were found1. The ion pairing effects are investigated by Diffusion-Ordered NMR (DOSY-NMR)-Spectroscopy experiments that give access to translational diffusion coefficients of anions and cations in dependence of temperature and concentration2. With the help of conductivity measurements and the Nernst-Einstein-equation the degree of dissociation is calculated.

NN OSO3

-

+

O60 bar H2, 60°C

[Ru/C]OSO3

-

NN +

OH

*

21 DOSY-NMR is also known to be a tool to determine aggregation number of ions3. This method was applied to determine the aggregation number of ionic liquids dissolved in solvents with different polarity.

Furthermore Ionic Liquids are presented as probe liquid for NMR-cryoporometry, a method to determine pore size distribution in porous media. This method is a promising tool to obtain a better understanding of the structural properties of catalyst, when the reaction is catalyzed by a SILP-catalyst (supported ionic liquid phase)4.

1 P. S. Schulz, N. Müller, A. Bösmann and P. Wasserscheid, Angew. Chem. Int. Ed., 2007, 46, 1293 2 K. Schneiders, A. Bösmannn, P.S. Schulz, P. Wasserscheid, Adv. Syn. Cat.2009 3 D. Zuccaccia, A. Macchioni, Organometallics 2005, 24, 3476-3486 4 A.Riisager, R.Fehrmann, M.Haumann, P.Wasserscheid, Eur. Jour. of Inorg. Chem. 2006, 4, 695-706.

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The SILP catalysis concept – molecular catalysis in heterogeneous systems

Peter Wasserscheid, Marco Haumann

Lehrstuhl für Chemische Reaktionstechnik, Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen; e-mail: [email protected]

The ultimate goal in the development of more efficient catalytic materials is to combine the selectivity, specificity and synthetic availability offered by a homogeneous catalyst with the ease of processing and the robustness that can be realized with heterogeneous catalysts. A very promising concept towards this goal of molecular catalysis in heterogeneous systems is the “Supported Ionic Liquid Phase (SILP)” catalyst technology. In a SILP catalyst an ionic liquid containing a dissolved transition metal complex is dispersed over the high internal surface of a porous support. Due to the very good wettability of ionic liquids on typical inorganic supports and due to the strong capillary forces, a material results that is macroscopically a dry solid but still contains the dissolved catalyst in its film on support. Due to the extremely low vapour pressure of ionic liquids the SILP materials show excellent stability in continuous gas phase contact (up to 1100 h time-on-stream demonstrated). A schematic representation of a SILP-catalyst is shown in Figure 1.

Figure 1: Schematic representation of a Supported Ionic Liquid (SILP) Catalyst. The contribution will summarize our recent advances in developing the SILP technology to an industrially accepted and applied catalyst technology. Important aspects of SILP catalysis will be highlighted for catalytic hydroformylation, asymmetric hydrogenation, water-gas-shift and Friedel-Crafts reactions. Moreover, our contribution will introduce concepts to use ionic liquids as modifiers for catalytic surfaces and new strategies to immobilize catalytic particles in ionic liquids. Mechanistic, reaction engineering and analytic aspects of these concepts will be equally discussed.

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Cellulose Hydrogenolysis in Ionic Liquids

Ignatyev Igor*, Koen Binnemans, Dirk De Vos*

Centre for Surface Chemistry and Catalysis *Katholieke Universiteit Leuven (Catholic University of Leuven); [email protected]

Cellulose can be used as a great bio-renewable source of many different compounds, e.g. sorbitol and ethanol. Today the problem of biofuels is quite important because sources of fossil fuels will be exhausted in the long run and fossil fuels utilization is linked to excessive production of greenhouse gases. In contrast to fossil fuels, cellulose-containing biomass is easily available as plant material. [1, 2]

Ionic liquids gained a great interest because it was proposed that they could replace conventional organic solvents in many cases. For cellulose processing they should especially be useful because there is only one well known classical solvent for this biopolymer – Schweizer’s reagent, an ammoniacal solution of copper monoxide. This solvent is too polluting to be used in contemporary technologies. Moreover, cellulose hydrogenolysis in Schweizer’s reagent gives only deep-degradation products – isopropyl alcohol, 1-hydroxy-2-propanone, propane-1,2-diol, CO2, CH4 etc. [3]

Our catalytic experiments started from simple compounds that mimic structural motivs of cellulose, e.g. ketals or cellobiose. Eventually, new conditions were identified for cellulose hydrogenolysis to sorbitol in an ionic liquid. The ionic liquid-of-choice is 1-butyl-3-methyl immidazolium chloride. The chloride anion, as a small hydrogen bond acceptor, destructs the three-dimensional network of cellulose OH-groups. [4] Imidazolium salts seem to be the most effective, with the smallest imidazolium cation exhibiting the easiest dissolution. [1]

The conditions include application of two catalysts including one homogeneous and one heterogeneous catalyst: HRu(Cl)(CO)(PPh3)3 and Pt/C. The homogeneous catalyst [HRu(Cl)(CO)(PPh3)3] requires the presence of base as the promoter. While the Pt/C is mainly involved in the hydrogenation of the intermediate glucose, the role of the homogeneous Ru complex is less clear. It might play a role in the activation of the carbohydrate residues in cellulose, but this is at present being elucidated.

The presence of all of three components (two catalysts and one promoter, KOH) is essential to get high product yields. We reached ca. 100% cellulose conversion with sorbitol as the major product (51 % selectivity) and glucose as the other product. The pressure (35 bars of H2) and temperature (150 °C) employed are lower than in many other examples reported for similar reactions. [3, 5, 6]

References 1. Patent WO 03/029329 A2, 2003. 2. P.L. Dhepe, A.Fukuoka. Cracking of Cellulose over Supported Metal Catalysts. // Catal Surv Asia. 2007. V

11. P. 186-191. 3. Patent US 2488722, 1946 4. J. Wu, J. Zhang, H. Zhang, J. He, Q. Ren, M. Guo. Homogeneous Acetylation of Cellulose in a New Ionic

Liquid. // Biomacromolecules. 2004. V. 5. P. 266-268. 5. P. A. J. Gorin. Hydrogenolysis of Carbohydrates: VIII. Comparative Studies on Methyl Glucopyranosides.

// Can. J. Chem. 1960. V. 38. P. 641–651. 6. P.L. Dhepe, A. Fukuoka. Cellulose Conversion under Heterogeneous Catalysts. // ChemSusChem. 2008.

969-975.

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Visible light driven water oxidation catalyzed by molecular Ru complexes in homogeneous systems

Licheng Sun, Lele Duan, Yunhua Xu

Department of Chemistry, School of Chemical Science and Engineering, Royal Institute of Technology (KTH), 10044 Stockholm, Sweden

Email: lichengs@kth.

In pursuit of solar energy conversion into a fuel by light-driven water splitting into H2 and O2，mononuclear Ru(II) complexes have been designed and synthesized as molecular catalysts for light-driven water oxidation which is still the bottleneck of the entire process. These molecular Ru(II) complexes showed efficiently catalytic properties towards both chemically and photochemically driven water oxidation in homogeneous solution. The turnover number of water oxidation by one Ru(II) catalyst reached 100 driven by visible light. During the process of oxygen evolution, a rare seven-coordinate Ru(IV) dimer complex containing a [HOHOH]− bridging ligand has been successfully isolated as an active intermediate, showing that water can attack directly to high valent six-coordinate Ru(IV) complex without ligand exchange. This work contributes to a deeper understanding of the reaction mechanism for catalytic water oxidation and will provide new possibilities for the design of more efficient catalysts for light-driven water oxidation.

Fig. 1 Visible light driven water oxidation with a three component system in pH 7.0 aqueous solution containing a photosensitizer, a sacrificial electron acceptor and a molecular catalyst. 1. S. Ott, M. Kritikos, B. Åkermark, L. Sun, R. Lomoth, Angew. Chem. Int. Ed. 2004, 43, 1006-1009. 2. L. Sun, B. Åkermark, S. Ott, Coord. Chem. Rev. 2005, 249, 1653-1663. 3. Y. Na, M. Wang, J. Pan, P. Zhang, B. Åkermark, L. Sun, Inorg. Chem. 2008, 47, 2805. 4. Y. Xu, T. Åkermark, V. Gyollai, D. Zou, L. Eriksson, L. Duan, R. Zhang, B. Åkermark, L. Sun, Inorg.

Chem. 2009, 48, 2717-2719.

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Photoinduced H2-production with Fe- and Co-based molecular catalysts

Mei Wang, Pan Zhang, Yong Na, Jingxi Pan, Xueqiang Li and Licheng Sun

State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology, Dalian 116012, China; Department of Chemistry, Royal Institute of

Technology (KTH), 10044, Stockholm, Sweden

In recent years, much progress has been achieved in developing and understanding of photoinduced H2 production by using homogeneous molecular catalyst systems, which are mainly composed of a metal-containing photosensitizer (PS), a molecular catalyst based on Pt, Pd, Rh, Co, and Fe, as well as sacrificial electron donor. We have demonstrated that the three-component system of Ru(bpy)3

2+, an [Fe2S2] complex, and ascorbic acid is catalytically active for photoinduced H2 production with TON up to 86 based on the Ru PS under an optimal condition.1 Coordinately self-assembled Zn(II) porphyrin-diiron dyads were found to evolve H2 in action of visible light by Kluwer and us independently.2,3 To improve the efficiency of the catalyst system, we have recently studied the three-component system with a cyclometalated iridium complex as PS, an [Fe2S2] catalyst, and triethylamine (TEA) as an electron sacrificer, which displays apparently higher activity and longer lifetime for the photoinduced H2 production as compared to other Fe-based catalyst systems either with Ru(bpy)3

2+ or Zn(II)-porphyrins as PS. Preliminary studies show that an attractive catalyst system of a cheap organic PS, a cobaloxime complex, and a tertiary amine is also catalytically active for H2 production in an aqueous solution.

Fig. 1 (a) The Fe-based catalyst system with a cyclometalated iridium complex as PS in acetone/water and (b) the Co-based catalyst system with a cheap organic PS in water. References: [1] Y. Na, M. Wang, J. Pan, B. Åkermark L. Sun, Inorg. Chem. 2008, 47, 2805−2810. [2] A.M. Kluwer, R. Kapre, F. Hartl, M. Lutz, A.L. Spek, A.M. Brouwer, P.W.N.M. van Leeuwen, J.N.H. Reek,

Proc. Natl. Acad. Sci. 2009, doi: 10.1073/pnas.0809666106. [3] X. Li, M. Wang, S. Zhang, J. Pan, Y. Na, J. Liu, B. Åkermark, L. Sun, J. Phys. Chem. B 2008, 112, 8198–

8202. Acknowledgment. This work was supported by the National Science Foundation of China (No. 20633020), the National Basic Research Program of China (No. 2009CB220009), the Swedish Energy Agency, the Swedish Research Council, and the K & A Wallenberg Foundation of Sweden.

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Cobaloxime-Catalyzed Hydrogen Electro- and Photo-Production

V. Artero, Pierre-André Jacques, A. Fihri and M. Fontecave

Laboratoire de Chimie et Biologie des Métaux, Université Joseph Fourier, CNRS, CEA/DSV/iRTSV CEA-Grenoble 17 rue des martyrs 38054 Grenoble cedex 9, France

[email protected]; Phone: (0033)438789106; Fax: (0033)

In the perspective of a hydrogen economy, one major issue concerns the availability of economically viable methods for the production of H2 from renewable sources. Reduction of protons is apparently a very simple reaction but unfortunately, except on platinum metals electrodes, suffers from kinetic limitations and is generally not observed at potentials near equilibrium (–400 mV vs SHE at pH 7 in water) but requires the application of an overvoltage. The development of new homogeneous electrocatalysts for hydrogen evolution based on cheap first-row transition metals has been a long-date goal for inorganic chemists. We will report and discuss on the activity of various cobalt and nickel complexes including

the cobaloxime [Co(dmgBF2)2(OH2)2], as electrocatalysts for the reduction of a variety of acids with different pKas in non-aqueous solvents.

In a second step, the cobalt catalysts have been coupled with photosensitive metal-diimine moieties in order to make supramolecular variants of the system previously studied by Lehn et al. for the photoproduction of H2. In these molecular devices, the intramolecular electron-transfer from the photoactivated center to the catalytic center can be controlled in a larger extend avoiding charge recombination processes, than in intermolecular systems by a fine tuning of the distance between metal centers and the nature of the bridge. Such an organized assembly is found with photosystem I tightly coupled to hydrogenase enzymes in hydrogen-evolving green-algae. These photocatalysts are able to achieve hydrogen photo-production in non-aqueous solvents with the highest efficiencies so far reported for such devices and already compete with similar systems based on molecular photosensitizers but using Pt nanoparticles as the catalytic centers.

References: Razavet, M.; Artero, V.; Fontecave, M. Inorg. Chem., 2005, 44, 4786. Baffert, C.; Artero, V.; Fontecave, M. Inorg. Chem., 2007, 46, 1817. Hu, X.; Cossairt, B. M.; Brunschwig, B. S.; Lewis, N. S.; Peters, J. C. Chem. Commun., 2005, 4723. Hawecker, J.; Lehn, J.-M.; Ziessel, R. Nouv. J. Chim. 1983, 7, 271. Fihri, A.; Artero, V.; Razavet, M.; Baffert, C.; Leibl, W.; Fontecave, M., Angew. Chem. Int. Ed. 2008, 47, 564. Fihri, A.; Artero, V.; Pereira, A.; Fontecave, M., Dalton transaction 2008, 5567. Du, P.; Knowles, K.; Eisenberg, R., J. Am. Chem. Soc., 2008, 130, 12576. Du, P.; Schneider, J.; Luo, G.; Brennessel, W.; Eisenberg, R., Inorg. Chem., doi: 10.1021/ic900389z Probst, B.; Kolano, C.; Hamm, P.; Alberto, R., Inorg. Chem. 2009, 48, 1836.

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Modelled after nature - photocatalytic water splitting with redoxactive metal complexes

Sven Rau, Johannes G. Vos

Department for Chemistry and Pharmacy, Friedrich-Alexander-University Erlangen Nürnberg, Egerlandstraße 1, 91058 Erlangen, Germany

e-mail: [email protected] SRC SEC School of Chemical Sciences Dublin City University, Dublin 9, Ireland

Photocatalytic splitting of water into hydrogen and oxygen using photochemical molecular devices requires a combination of photochemically and redox active metal centres, a bridging ligand and a catalytic centre. Several of these devices already exist for the hydrogen production, however to the best of our knowledge none of them is stable against oxygen.1 As oxygen is the final oxidation product of the overall water splitting this stability is crucial. We here present a study on Ru-BL-M systems which produce hydrogen and show a significant stability against oxygen. The ruthenium centre contains as bridging ligand 4,4’-dinitril-2,2’-bipyridine.3

1. Rau, S.; Walther, D. ; Vos, J.G., Dalton Trans. 2007, 915-919 2. Fihri, A.; Vincent A.; Razavet, M.; Baffert, C.; Leibl, W.; Fontecave, M.; Angew. Chem. 2008, 564-567 3. Losse S., Görls, H., Rau, S.; Groarke, R.; Vos, J. G.; Eur. J. Inorg. Chem. 2008, 4448-4452

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Towards Catalytic Water Oxidation: Model Systems for PS II

Björn Åkermark,1 Yunhua Xu,2 Viktor Gyollai,2 .Yan Gao,1 Jianhui Liu,3 Torbjörn Åkermark,4 Licheng Sun2

1Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stocjholm, Sweden 2Department of Chemistry, Royal Institute of Technology (KTH), 10044 Stockholm, Sweden

3State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Centre on Molecular Devices, Dalian University of Technology, Dalian 116012, China;

4Department of Chemical Technology, Royal Institute of Technology (KTH), 10044 Stockholm, Sweden

During the last 20 years, extensive efforts have been devoted to the development of systems for converting solar energy and water into a fuel, by reducing either protons to hydrogen or carbon dioxide to eg methanol. Much of the work has been based on modeling natural photosynthesis. In PS II, the electrons that are used for reduction of carbon dioxide are abstracted from water, converting two molecules of water into molecular oxygen and protons. Not surprisingly, this turns out to be a very difficult process to model. A break through in our own efforts was the preparation of a complex, where a ruthenium photosensitizer is linked to a dinuclear manganese moiety and able to oxidize this stepwise from MnII/II to MnIII/IV. However, on further oxidation, the ligand appears to be oxidized instead of water. We have therefore studied a considerable number of dinuclear manganese complexes with more sturdy ligands, but so far these experiments have been unsuccessful. However, ligands based on corroles have been more successful, and we have recently shown that electrochemical oxidation of water can be accomplished by a dinuclear Mn-corrole complex. Using a corrole complex, we have also been able to demonstrate for the first time that nucleophilic attach by hydroxide on a Mn(V) oxo complex is a viable mechanism for the formation of the crucial O-O bond in water oxidation.

Since ruthenium complexes have long been known to catalyze water oxidation, we have also recently prepared the dinuclear Ru(II) complexes 1-3, and shown that these complexes are efficient catalysts for water oxidation. These complexes still require stronger oxidants than Ru(III)(bpy)3 to convert water into oxygen but a further development along these lines is presented in the following report by Prof Sun.

N N

N

N

OO

OO

Ru

N

N

N

Ru

N

N

N

PF6

N N N

NN

NRu Ru

Cl

N

NN

N

3PF6

21

N N

N

N

O

Ru

N

N

N

Ru

N

N

N

PF6

3

O

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Nucleophilic Addition Step of the Wacker Process: Mechanistic Answers from Molecular Dynamics in Water

Aleix Comas-Vives,1 András Stirling,2,* Agustí Lledós1 and Gregori Ujaque1,* 1Unitat de Química Física, Departament de Química, Edifici Cn, Universitat Autònoma de Barcelona, 08193

Bellaterra, Catalonia, Spain [email protected]

2Chemical Research Center of HAS, Pusztaszeri út 59-67, H-1025, Budapest, Hungary

The Wacker process was the first organometallic catalytic oxidation industrially applied[1,2] and it involves the oxidation of ethylene to acetaldehyde in aqueous solvent.

The most controversial reaction step is the hydroxypalladation of ethene. The debate relies on the mode of the water nucleophilic attack on ethene: (a) via an inner-sphere mechanism from a coordinated water to palladium (syn-addition), or (b) via an outer-sphere mechanism of a water molecule from the bulk (anti-addition). This step has been intensively investigated both experimentally and theoretically but the dicotomy between both mecanism has been not entirely solved.[3,4] This controversy about the nucleophilic addition in the Wacker process has been addressed by means of first principles molecular dynamics simulations in a box containing 26 water molecules. The two modes for the nucleophilic attack, syn-inner sphere and anti-outer sphere mechanisms along with the new found alternatives have been evaluated. The free energy barriers obtained for the anti additions are in very good agreement with experiment, and significantly lower than that for the syn additions. Additionally, this work shows that metadynamics coupled with Car-Parrinello Molecular Dynamics offers a very efficient framework to investigate and understand transition metal catalyzed reactions in aqueous phase and may help to develop other aqueous phase processes, a key challenge in green chemistry.

Cl

Pd

Cl

ClCl

Cl

Pd

Cl

Cl

Cl

Pd

OH2

Cl

2-

Cl

Pd CH2ClCl

Pd

H

Cl

OH

Cl

PdClOH

Cl

Pd

OH

Cl

Cl-

C2H4

CHOHH

Cl-

H2O

H+

H2O

Nucleophilic addition step

HCl

O

H

a

+2CuCl

2CuCl2

syn-inner

anti-outer

-H+

1/2 O22HCl

H2O

b

[1] J. Smidt, W. Hafner, R. Jira, J. Sedlmeier, R. Sieber, R. Ruttinger, H. Kojer, Angew. Chem. Int. Ed.

1959, 71, 176. [2] J. Smidt, J. Sedlmeier, W. Hafner, R. Sieber, A. Sabel, R. Jira, Angew. Chem. Int. Ed. 1962, 74, 93. [3] P. E. M. Siegbahn, J. Phys. Chem. 1996, 100, 14672. [4] J. A. Keith, R. J. Nielsen, J. Oxgaard, W. A. Goddard, J. Am. Chem. Soc. 2007, 129, 12342.

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An All-Inorganic, Highly Active Tetraruthenium Homogeneous Catalyst for Water Oxidation. Reaction Mechanism

Yurii V. Geletii, Claire Besson, Zhuangqun Huang, Yu Hou, Qiushi Yin, Djamaladdin G. Musaev, David Quinonero, Alexsey Kuznetsov, Rui Cao, Kenneth I. Hardcastle, Anna

Proust,* Bogdan Botar,** Paul Kögerler,** Tianquan Lian and Craig L. Hill

Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, GA 30322, USA. *IPCM, Université Pierre et Marie Curie, 4 Place Jussieu, F-75005 Paris. **Institut für

Festkörperforshung, Forshungszentrum Jülich GmbH, G-52425

The conversion of light energy into chemical potential is accomplished by natural photosynthesis in several steps. Light gathering and charge separation result in generation of oxidizing and reducing equivalents. The reducing equivalents are used to convert CO2/H2O into biomass, while the oxidizing equivalents must be consumed to catalytically oxidize water to O2. Thus, with respect to both natural and/or artificial photosynthesis, O2 is an unavoidable and stoichiometric by-product. Recently,1 we reported that the organic-structure free complex, Rb8K2[{Ru4O4(OH)2(H2O)4}(γ-SiW10O36)2] (1), efficiently catalyzes stoichiometric oxidation of water by [Ru(bpy)3]3+ at neutral pH, eq 1.

4 [Ru(bpy)3]3+ + 2 H2O → 4 [Ru(bpy)3]2+ + O2 + 4 H+ (1)

Simultaneously and completely independently, Bonchio et al developed the same catalyst,2 but used Ce(IV) as an oxidant under very acidic conditions.

We report here the extensive characterization of this tetra-ruthenium complex, including establishment of its oxidation states, the stability and protonation states of the different oxidation states including an X-ray structure of the form one-electron more oxidized than 1, and some features of its electronic structure. The detailed thermodynamic analysis and kinetic studies facilitated identification of the O2-evolving species: the complex in which all ruthenium atoms are in the 5+ oxidation state. The latter one is formed from 1 via four sequential 1-electron oxidation by [Ru(bpy)3]3+. The reaction proceeds quickly in the presence of 2-8 μM 1 with O2 yields up to 75% and turnover numbers, TON = [O2]/[1], up to ~102.

We have also developed a photocatalytic system in which the [Ru(bpy)3]3+ is generated from [Ru(bpy)3]2+ by photooxidation using persulfate ions, S2O8

2-, as a sacrificial electron acceptor (eq 2). The [Ru(bpy)3]3+ formed is then used to oxidize water in eq 1.

2 [Ru(bpy)3]2+ + S2O82- + hν → 2 [Ru(bpy)3]3+ + 2 SO4

2- (2)

Dioxygen is formed quickly under visible light (420-520 nm) illumination, while persulfate is consumed. The O2 yield (per persulfate, eq 2) is ca 40% with TON up to ~3.5x102 and with a turnover frequency up to ~3x102 h-1. The quantum yield is estimated to be ≥ 9%. Acknowledgement. This work was supported by the U.S. Department of Energy (DE-FG02-03ER-15461 and DE-FG02-07ER-15906). (1) Geletii, Y. V.; Botar, B.; Kögerler, P.; Hillesheim, D. A.; Musaev, D. G.; Hill, Craig L. Angew. Chem. Int. Ed. 2008, 47, 3896. (2) Sartorel, A.; Carraro, M.; Scorrano, G.; Zorzi, R. D.; Geremia, S.; McDaniel, N. D.; Bernhard, S.; Bonchio, M. J. Am. Chem. Soc 2008, 130, 5006.

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High Pressure Infrared and NMR Studies of Catalytic Systems in Carbonylation Reactions

Philippe Kalck

Université de Toulouse, Laboratoire de Chimie de Coordination UPR8241, Equipe de Catalyse et Chimie Fine, composante ENSIACET-Institut National Polytechnique de Toulouse, 118, route de Narbonne, 31077 Toulouse

Cedex (France)

In order to have an access to the intimate running of a catalytic system, it is most often necessary to make extensive kinetic studies and to validate the existence of short-lived intermediate species. Spectroscopic studies performed in the real catalytic conditions allow identifying key complexes, provided the concentrations of the species are sufficiently high. However, it is necessary to identify if these species are involved in the catalytic cycle or are derived complexes. In our laboratory, we have developed high pressure-infrared and -NMR studies, which are powerful tools to follow in situ carbonylation reactions mainly catalysed by noble metals. Moreover, using labelled reactants, such as 13CO, 13CH3I, provides more precise information leading to a better understanding of the catalytic system.

Thus, we have been able to intercept a pentacoordinated palladium species, [Pd(H)(SnCl3)(CO)(PCy3)2], supporting the presence of an active hydrido-palladium entity involved in the alkoxycarbonylation reaction of alkenes to produce the corresponding esters.

Similarly, we succeeded in demonstrating that the active species in the hydroformylation reaction of alkenes, using a cobalt/pyridine system in a ionic liquid medium, is the [Co(H)(CO)4] hydride under working conditions (100 bar, 120°C), whereas under ambient conditions the [Co(py)6][Co(CO)4]2 is recovered in the ionic liquid phase.

Moreover, we were able to identify the exact role played by platinum to assist the iridium catalyst in the methanol carbonylation reaction leading to acetic acid. This determining step is shown below on the Figure:

IOC

IrII

Pt COOCOC

Me

Me

I

I

IrII

OCOC

Me

I I

PtII

PtCO

OCI

I1/2

I Pt COI I

IrII

OCOC

Me

I

-

[MeIrI3(CO)2]-

-

-

- More recently we have extent our studies to selective hydrogenation reactions. Main references: D. H. Nguyen, G. Laurenczy, M. Urrutigoïty et Ph. Kalck, Eur. J. Inorg. Chem. (2005) 4215-4225 F. Hébrard, Ph. Kalck, L. Saussine, L. Magna and H. Olivier-Bourbigou, Dalton Trans. (2007) 190-191 S. Gautron, N. Lassauque, C. Le Berre, Ph. Serp, L. Azam, R. Giordano, G. Laurenczy, D. Thiébaut and Ph. Kalck, Eur. J. Inorg. Chem. (2006) 1121-1126

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Well-defined silica-grafted calcium reagents: hybrid materials for supported catalysis

Régis M. Gauvin,1,* Frank Buch,2 Laurent Delevoye,1 Sjoerd Harder2,* 1 Unité de Catalyse et de Chimie du Solide UMR CNRS 8181, Ecole Nationale Supérieure de Chimie, BP 90108,

59 652 Villeneuve d’Ascq Cedex (France) 2 Anorganische Chemie, Universität Duisburg-Essen, Universitätsstrasse 5, 45117 Essen (Germany)

Current interest in calcium organometallic species stems from their rapid-growing application as green catalysts, as well as from calcium’s wide accessibility and low cost. These reagents have been shown to be active in key transformations, including i.a. styrene polymerization, olefin hydrosilylation and even hydrogenation.1 Ideally, organometallic synthesis would allow access to tailor-made catalysts of the type [Ca(LS)(LR)], where LS is a spectator ligand and LR is a reactive moiety able to initiate catalysis. However, the Schlenk equilibrium often interferes and redistribution of ligands affords a mixture of homoleptic species:2

LS Ca LRLS Ca LS

LR Ca LR2 +LS Ca

LR

LS

Ca LR

In order to overcome this problem, grafting of calcium reagents onto silica appears as a promising strategy. Using a rationale approach, we have been able to generate catalytic materials bearing single site species of the type (≡SiO)Ca(LR) (where LR is a benzyl or amide ligand).3 These materials have been fully characterized, most particularly using high field solid-state-NMR (18.8T). Model studies on molecular compounds have demonstrated that access to stable heteroleptic siloxybenzyl or amide calcium derivatives is not possible, demonstrating the validity of our grafting approach.

These hybrid materials are active in several catalytic processes, with remarkable properties. In styrene polymerisation, dramatic increase in syndiospecifity compared to molecular catalysts is observed, while good activities in olefin hydrosilylation are obtained. Recycling of the catalyst is hampered by deactivation, for which we propose mechanisms based on spectroscopic studies.

1) a) S. Harder, F. Feil, K. Knoll, Angew. Chem. Int. Ed. 2001, 40, 4261; b) M. R. Crimmin, I. J. Casely, M. S. Hill, J. Am. Chem. Soc. 2005, 127, 2042; c) F. Buch, J. Brettar, S. Harder, Angew. Chem. Int. Ed. 2006, 45, 2741; d) J. Spielmann, F. Buch, S. Harder, Angew. Chem. Int. Ed. 2008, 47, 9434. 2) W. Schlenk, W. Schlenk, Jr., Ber. Dtsch. Chem. Ges. 1929, 62B, 920-924 3) R. M. Gauvin, F. Buch, L. Delevoye, S. Harder, Chem. Eur. J. 2009, 15, 4382-4393.

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Biomimetic Oxidation Catalyst Immobilised on Silicon Wafers and Silicon Particles

Emmanuelle Göthelid, Kristofer Eriksson, Jan-E. Bäckvall, Carla Puglia, Winnie Chow and Sven Oscarsson*

Dept. of Physics and Materials Sciences, Uppsala University, Box 530, S-75121, Uppsala, Sweden

Thiol-functionalized cobalt por-phyrins (CoTPP-L), shown in Figure 1a), were immobilized to silicon wafers and on solid silicon based particles of various dimensions. The activity in the catalytic oxidation of hydroqui-none to benzoquinone illustrated in Figure 1b) has been com-pared on the two different kinds of supports, the number of catalytic units being determined by ICP (Inductively Coupled Plasma).

The silanisation reaction on wafers, described in figure 1c), has been optimized to be able to obtain a monolayer of the catalyst on the wafers. This makes it possible to investigate the effect of the orientation and

the organization of the cobalt catalyst on the support surface, determined with Scanning Probe Microscopy (SPM) and Photoelectron Spectroscopy (PES), onto the observed turnover frequency of the catalytic reaction. Earlier publications on CoTPP-L immobilized to gold wafers shown a 100 times higher catalytic activity compared to its homogenous counterpart. Preliminary studies of the behavior of the catalyst on a fully biome-metic system according to Figure 2 are under course.

Figure 1. (a) Chemical structure of the CoTPP-L molecule. (b) Catalytic reaction under investigation: oxidation of hydroquinone to benzoquinone under the consumption of oxygen in presence of porphyrins. The experiments were run in acetic acid. (c) Immobilization reaction CoTPP-L including silanisation step of the silicon wafers.

OHOH

OO

H2O

1/2 O2

HQ

BQ

MOX

MRED

+H2O

Cobalt porphyrin

Pd(II)

Pd(0) +2H+

Reactant

OxidizedProduct

Figure 2. Schematic representation of the redox reactions of the biomimetic triple catalytic system employing an electron-transfer mediator (EMT), developed by Bäckvall and coworkers.

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77

Studies of Enantioselectivity at Well Defined Supported Heterogeneous Catalysts

Gary A. Attard

School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, UK

There are two ways in which chirality may be bestowed on a metal surface. The first is to synthesise an intrinsically chiral surface from a single crystal by judicious choice of an appropriate Miller index surface plane [1]. The second is to adsorb a chiral organic molecule onto the metal surface such that chiral adsorption sites associated with the organic adsorbate are produced [2]. Both methods of surface modification will be described with emphasis placed on changes in surface chirality engendered by variations in surface composition. In particular, the use of bimetallic PtPd surface alloy films supported on Pt{hkl}r/s electrodes will be discussed in relation to D- and L- glucose electrooxidation and compared with previous results obtained using both Pt{hkl}r/s and bulk alloy PtPd{hkl}r/s surfaces [3]. Furthermore, new results for the enantioselective hydrogenation of ethyl pyruvate on bimetallic supported catalysts in the presence of cinchona alkaloid modifiers will be used to confirm the pre-eminence of platinum as being the best catalyst for this particular chemical transformation. The use of surface-enhanced Raman spectroscopy to identify surface intermediates will also be discussed.

0 1 2 3 4 5

0

10

20

30

40

50

60

Steps

Terraces

Ena

ntio

mer

ic E

xces

s / %

R

θPd

0 1 2 3 4 5 6

0

10

20

30

40

50

Ena

ntio

mer

ic E

xces

s /%

R

θPt

}

Figure 1 Changes in enantioselectivity of ethyl pyruvate hydrogenation caused by adsorbing: (LEFT) Pd on a 5%Pt/Graphite catalyst (θPd coverage in monolayers). Curly bracket indicates coverage range of filling of surface step sites. (RIGHT) Adsorbing Pt on a 5%Pd/Graphite (θPt coverage in monolayers). References [1]C.F. McFadden, P.S. Cremer, A.J.Gellman, Langmuir 12 (1996) 122483. [2] M. Studer and H.-U. Blaser, Adv. Syn. & Catal. 45 (2003). [3] D.J. Watson and G.A. Attard, Electrochimica Acta 46 (2001) 3157.

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Posters

P1-P154

79

80

Convenient and Regioselective bromination of phenol using Zeolite as a heterogeneous catalyst

M. Abrishamkara,d , S. N. Azizia,* and H. Kazemianb,c

a) Analytical Division, Faculty of Chemistry, University of Mazandaran, Babolsar, Iran, P.O.Box: 47416-95447. b) Department of Chemical and Process Engineering, Faculty of Engineering, Universiti Kebangsaan Malaysia

(UKM), 43600 UKM, Bangi, Selangor, Malaysia c) SPAG Zeolite R&D Group. Technology Incubation Centre, Science and Technology Park of Tehran

University, Tehran, Iran d) Department of Chemistry, Islamic Azad University P. G. Study and Research Center, Ahvaz, Iran.

ZSM-5 zeolite due to its unique channel structure, thermal stability, acidity and shape-selective property, has been used as sorbent and catalyst in several petrochemical processes, fine chemical reactions, and liquid and gas separation [1, 2]. ZSM-5 zeolites show excellent catalytical performance in a lot of organic transformation reactions. Zeolites catalysts are used to produce hundred millions of barrel of petroleum every year [3]. Protonic zeolites find industrial applications as acid catalysts in several hydrocarbon conversion reactions [4, 5].

HZSM-5 zeolite was successfully synthesized with different silicon to aluminum molar ratios (Si/Al) in range of 14.5 to 58. As synthesized zeolites were characterized using FT-IR, XRD, and SEM techniques. The nuclear as well as side-chain bromination of activated aromatic substrates has been achieved in high yields and substantial regioselectivity with N-boromosaccharins (NBSac) over HZSM-5. Successful bromination of phenol has been achieved on the examined HZSM-5 catalysts. Catalyst sample with Si/Al of 58 was shown the highest reaction yield in the lowest times.

References [1] C. Falamaki, M. Edrissi, M. Sohrabi, Zeolite, 19 (1) (1997) 2-8. [2] N. Kumar, V. Nieminen, K. Demirkan, T. Salmi, D. Y. Murzin, E. Laine, Appl. Catal. A: Gen. 235 (2002) 113-123. [3] J. Shan, L.Shituna, L.F. Wang; J.MOL.Catal.16 (5) (2002) 379. [4] N.Y. Chen, W.E. Garwood, F.G. Dwyer, Shape Selective Catalysis in Industrial Applications, 2nd ed., Dekker, New York, 1996. [5] M. Guisnet, J.P. Gilson (Eds.), Zeolites for Cleaner Technologies, Imperial College Press, London, 2002.

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81

Iron-Catalyzed Hydrosilylation of Ketones

Daniele Addis, Nadim S. Shaik, Kathrin Junge and Matthias Beller *

Leibniz-Institut für Katalyse e.V. an der Universität Rostock * Leibniz-Institut für Katalyse e.V. an der Universität Rostock

Recently, we started a program to develop more sustainable catalysts by replacing precious metal by non-precious ones and, according to the concept “cheap metals for noble tasks”, the possibilities of iron catalysts are especially attractive for us. Iron is the second most abundant metal after aluminium available on earth. Indeed, for several chemical trasformations iron has been prove to be an useful catalyst,

[1].

During the last three years various examples of iron-catalyzed hydrosilylation of aldehydes and prochiral ketones have been showed by the groups of Nishiyama,

[2] Gade, [3] Beller, [4] Nikonov, [5] and Chirik. [6] We have demonstrated that the in situ system constituted by Fe(OAc)2, a basic phosphine (PCy3 or (S,S)-Me-DuPhos for the asymmetric hydrosilylation) and an economical hydride source as polimethylhydrosiloxane is able to catalyze the reduction of several ketones and aldehydes in good to excellent yields and, in the case of prochiral ketones and with the use of the DuPhos ligand, high enantioselectivity up to 99% ee can be achieved. The protocol tolerates several functional groups such as esters, halides as well as conjugated double bonds with high chemoselectivity. As an additional advantage of the present catalytic system, there is no need of any activating agent or additive. We believe that the present investigation is an important step towards general asymmetric reductions with iron catalysts.

R'

O

R'

OH1. Fe(OAc)2Ligand

(EtO)2MeSiH or PMHSTHF, RT2. aq. base

up to 99% yield,99% ee

R R

P

P

(S,S)-Me-DUPHOS

P or

Tricyclohexylphosphine

1 (a) For a review on iron catalysis see: Bolm, C.; Legros, J.; LePaih, J.; Zani, L. Chem. Rev. 2004, 104, 6217-6254. (b) Enthaler, S., Junge, K., Beller, M., Angewandte Chemie Int. Ed. 2008, 47, 3317. 2 Nishiyama, H., Furuta, A., Chem. Commun. 2007, 760–762. 3 B. K. Langlotz, H. Wadepohl, L. H. Gade, Angew. Chem. Int. Ed. 2008, 47, 4670–4674. 4 N. Shaikh, K. Junge, S. Enthaler, M. Beller, Angew. Chem. Int. Ed. 2008, 47, 2497–2501. 5 D. V. Gutsulyak, L. G. Kuzmina, J. A. K. Howard, S. F. Vyboishchikov, G. I. Nikonov, J. Am. Chem. Soc. 2008, 130, 3732-3733. 6 A. M. Tondreau, E. Lobkovsky, P. J. Chirik, Org. Lett. 2008, 10, 2789-2792.

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82

Mechanistic investigation of enantioswitchable catalysts for asymmetric transfer hydrogenation

Katrin Ahlford, Jesper Ekström, Alexey B. Zaitsev, Per Ryberg and Hans Adolfsson

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden; email: [email protected]

Amino acid derived thioamides and hydroxamic acids have been used as ligands in the rhodium catalyzed asymmetric transfer hydrogenation of prochiral ketones in 2-propanol. Interestingly, the use of the two different types of ligands resulted in products of opposite configuration. [1,2]

A structure/activity correlation with differently functionalized or substituted ligands was investigated. The results indicate that the enantioswitchable nature of the thioamide- and hydroxamic acid based catalysts originates from the coordination mode of ligands.

From kinetic measurements, it was further found that the reaction differs in rate determining step depending on the catalyst used. For the reaction catalyzed by the hydroxamic acid-derived complex, the formation of the metal hydride is rate limiting, whereas reduction of the substrate is rate limiting in the reaction catalyzed by the thioamide-derived complex. Rate constants were also determined for the different steps.

High ee S High ee R

References: [1] Ahlford, K.; Zaitsev, A. B.; Ekström, J.; Adolfsson, H., Synlett, 16, 2541-2544 (2007). [2] Zaitsev, A. B.; Adolfsson, H., Org. Lett., 8, 5129-5132 (2006).

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83

Ru- and CALB-Catalyzed DYKAT 1,2-Diols

Nanna Ahlsten, Eduardo Busto, Michaela Vallin, Belén Martín-Matute,* and Jan-E.Bäckvall*

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden [email protected]

In an enzyme-catalyzed kinetic asymmetric transformation (KAT) of a diastereomeric 1:1 syn:anti mixture of 1,2-diols, the maximum theoretical yield of one enantiomer is 25%. This is a severe limitation, and to overcome it, we have combined an enzyme-catalyzed KAT with a Ru-catalyzed epimerization, and an intramolecular acyl migration in one pot.1 In this way, enantiopure acetates can be obtained in a 100% theoretical yield. This dynamic kinetic asymmetric transformation (DYKAT) has been applied to a variety of aromatic vicinal 1,2-diols.2 Mechanistic investigations explaining the enantio- and diastereoselectivity obtained will also be presented.2

References 1. M. Edin, B. Martín-Matute, J.-E. Bäckvall, Tetrahedron: Asymmetry 2006, 17, 708. 2. N. Ahlsten, E. Busto, M. Vallin, B. Martín-Matute, J.-E. Bäckvall, unpublished results.

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84

Non classical Ruthenium Hydride Complexes in Transfer- Hydrogenation Reactions

Javed Ahmad, Markus Hölscher, Walter Leitner

[email protected]; Institut für Technische und Makromolekulare Chemie, RWTH Aachen

Catalytic hydrogenation and dehydrogenation reactions play a major role in industrial as well as in academic research. Non-classical metal hydride complexes are catalytically active in various reactions because they contain a labile dihydrogen ligand and a reactive hydride[1]. They can be seen as intermediates in hydrogenation and dehydrogenation reactions and are therefore considered as potential hydrogen-transfer catalysts.

Metal-catalyzed hydrogen-transfer reductions of unsaturated organic substrates are mild methodologies for the reduction of unsaturated compounds and are of practical importance[2]. Investigations on the application of non-classical Ruthenium hydrides in catalytic transfer hydrogenation reactions are rare[3], opening an interesting potential for research in this area.

We have synthesised different types of non-classical ruthenium hydride complexes stabilised by mono-, di- and tridentate pincer type ligands and tested them in catalytic C=C and C=O bond transfer hydrogenation reactions. Conventional model substrates as well as biomass based molecules have been hydrogenated in the presence of 2-propanol as a hydrogen donor. Preparative results, kinetic investigations and mechanistic aspects will be presented.

[1] P. J. Jessop, R. H. Morris, Coord. Chem. Rev. 1992, 121, 155-284. [2] J. S. M. Samec, J.-E. Bäckvall, P. G. Andersson, P. Brandt, Chem. Soc. Rev. 2006, 35, 237-248. [3] C. Bianchini, M. Peruzzini, E. Farnetti, J. Kaspar, Organomet. Chem. 1995, 488, 91.

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85

Towards dynamic kinetic resolution of 2-phenylpropionates through combination of organo- and biocatalysis

María Alfaro-Blasco and Harald Gröger

Department of Chemistry and Pharmacy, University of Erlangen-Nuremberg, Henkestr. 42, 91054 Erlangen, Germany; E-mail: [email protected]

In the last decades there has been an increased number of syntheses of enantiomerically pure compounds based on enzymatic processes as alternative to conventional chemical methods.[1] Biocatalysis turned out to be useful, e.g., for the preparation of enantiomerically pure pharmaceutically relevant compounds. A popular approach towards those type of molecules is by means of dynamic kinetic resolution.[2] The aim of our current work is the development of a dynamic kinetic resolution process (starting from racemic esters) for the preparation of enantiomerically pure 2-phenyl-propionic acids such as (S)-naproxen, (S)-ibuprofen and related molecules.[3] The synthetic concept is based on a combination of an enantioselective enzymatic ester hydrolysis with a coupled base-catalyzed in situ racemisation (Scheme 1).

We investigated the activity of different lipases with respect to their hydrolytic activity. In this screening a lipase has been identified which hydrolyzed racemic 2-phenylpropionates rac-1 achieving enantioselectivity values of E=8-9. The reaction proceeded under room temperature in an organic-aqueous two-phase solvent system consisting of water and MTBE. In addition, different bases as catalysts were tested for the racemization of substrate (S)-1. Notably, the use of the achiral base TBD resulted in a complete racemization after ten hours.

OR

O

OR

O

OH

O

rac-substrate

(R= Et, Pr, Bu)

enantioselectiveenzymatic hydrolysis

base-catalyzedin situ racemization

OH

O

(S)-1

(R)-1 (R)-2

(S)-2

Scheme 1: Concept of a dynamic kinetic resolution of racemic 2-phenylpropionates 1 [1] K. Drauz, H. Waldmann (eds.): Enzymes in Organic Synthesis, vol. 1-3, Wiley-VCH, Wiley-VCH, 2002. [2] O. Pamies, J.-E. Bäckvall, Chem. Rev. 2003, 103, 3247-3261. [3] For enzymatic syntheses of (S)-naproxen and related molecules with lipases, see: a) T. Bando, Y. Namba, K. Shishido Tetrahedron: Asymmetry 1997, 8, 2159-2165, b) C.-S. Chang, S.-W. Tsai, C.-N. Lin, Tetrahedron: Asymmetry 1998, 9, 2799-2807; c) H.-Y. Lin, S.-W. Tsai, J. Mol. Catal. B: Enzym. 2003, 24, 111-120.

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86

Catalyst Selection for Monoethylene Glycol Production

Mehmet Rıza Altiokka and Sema Akyalҫin

Anadolu University, Department of Chemical Engineering, İki Eylül Campus, 26555, Eskişehir, TURKEY [email protected], [email protected]

Monoethylene glycol (MEG) is used in the manufacture of polyester resins, antifreezes, solvents, etc. and it is commonly produced by the hydration of ethylene oxide. During the reaction, diethylene glycol (DEG) and triethylene glycol (TEG) are produced as by-products [1, 2].

The hydration of ethylene oxide proceeds a series-parallel reactions [1, 2]:

H2O + C2H4O HOCH2CH2OH ⎯→⎯1k

⎯→⎯ 2k

⎯→⎯ 3k

1 2 3EtO W EtO MEG EtO DEG EtOr k C C k C C k C C- = + +

HOCH2CH2OH + C2H4O HO(CH2CH2O)2H

HO(CH2CH2O)2H + C2H4O HO(CH2CH2O)3H

Ethylene oxide can be hydrated either catalytically or non-catalytically. Non-catalytic hydration of ethylene oxide for the production of MEG is a well-known process in which large amount of water is used. This increases the product seperation cost. Furthermore, the reaction has to be carried out at high temperature to increase the reaction rate appreciably, which causes extra energy consumption. On the other hand, catalytic hydration of ethylene oxide can be performed at low temperature and low water/EtO mol ratios. Moreover, MEG selectivity can be increased by choosing the proper catalyst. The solid catalysts like an ion exchange resin can be easily filtered from the reactor liquor and used repeatedly. It is also reported that they minimize corrosion [2, 3]. In the present work, Amberjet 4200, Lewatit MonoPlus 500, Dowex SBR and Dowex Marathon A resins in their HCO3

- form were tested as the heterogeneous catalysts. The performance of these ion exchange resins were compared with each other at the same reaction conditions and conversion level in view of MEG selectivity and catalyst activity. The reaction was conducted in a pressurized batch reactor at 358 K and water/EtO mol ratio of 5:1. In each case, a different type of catalyst containing the equivalent amount of HCO3

- which is corresponding to 0.23 mol/L, was used. It is found that, although MEG selectivity did not differ much by catalyst type, Amberjet 4200/HCO3

- has showed the highest catalytic activity among the others. It increased the average reaction rate nine times relative to the uncatalyzed reaction. The kinetic model based on a series-parallel, irreversible, homogeneous reactions in elementary base was developed. Thus, the reaction rate was given to be

. The reactions were realized, in the presence of Amberjet 4200/HCO3

- corresponding to 0.15 mol HCO3-/L, at different temperatures.

Temperature dependency of the rate constants were found to be: k1=exp (19.96-9700/T) L/mol·min, k2=exp (20.55-10290/T) L/mol·min and k3=exp (19.33-9830/T) L/mol·min where T is absolute temperature in K.

References 1. Kirk, R.E.; Othmer, D.F., Encyclopaedia of Chemical Technology; J. Wiley: New York, 1984. 2. Weissermel, K.; Arpe, H.J., Industrial Organic Chemistry; VCH: New York, 1993. 3. Othmer, D.F.; Thakar, M. S., Ind. Eng. Chem., Vol. 50, No.9, 1958.

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Mesoporous molecular sieves immobilized Ru catalysts for olefin metathesis

Hynek Balcar , David Bek and Naděžda Žilková

J. Heyrovský Institute of Physical Chemistry AS CR, v.v.i, Dolejškova 3, 182 23 Prague 8, Czech Republic

Olefin metathesis is an important organic reaction, which has numerous important applications in petrochemistry, polymer chemistry and fine chemical synthesis [1]. Ru based complexes are the most popular metathesis catalysts due to their high activity and tolerance to the variety of functional groups in substrate molecule. The high cost of Ru complexes used and the demands on product purity stimulate the development of Ru heterogenized catalysts, which enable easy catalyst - product separation and catalyst reusing.

Mesoporous molecular sieves [2] represent advantageous supports for heterogeneous catalysts due to their large surface areas, large void volumes and narrow pore size distributions of mesopores. Using siliceous mesoporous molecular sieves SBA-15 (SBET = 915 m2/g, V = 1.1 cm3/g, d = 6.3 nm) as a support, heterogenized catalysts were prepared by immobilization of Ru complexes 1 – 4 (either by direct reaction with surface OH group or by carboxylate linkers [3]). The activity of the catalysts was tested in ring closing metathesis (RCM) of diethyl diallylmalonate (eq. 1) and ring opening metathesis polymerization (ROMP) of norbornene (eq. 2) as the model reactions.

Ru Ru

Cl

Cl

Cl

Cl

1O

Cl

RuCl

Mes MesN N

R 3 R = H4 R = SO2NMe2

RuCl

ClP

2

CO2EtEtO2C CO2EtEtO2C (eq. 1)

n

n (eq. 2)

In RCM of diethyl diallylmalonate, catalysts 3 and 4 exhibited high activity and after separation from reaction mixture they were reused several times without significant loss in activity. In ROMP of norbornene, catalysts 1 – 4 delivered high molecular weight polymers in high yields. Filtration test proved that the catalytic activity is bound to the solid phase. Polymers with reduced amount of catalyst residues were obtained. [1] Grubbs R.H., (Ed.), Handbook of Metathesis, Wiley-VCH, Weinheim, 2003. [2] Beck, J.S., Vartuli, J.C., Roth, W.J., Leonowicz, M.E., Kresge, C.T., Schmitt, K.D., Chu, C.-W., Olson,

D.H., Sheppard, E.W. , McCullen, S.B.,Higgins, J.B., Schlenker, J.L., J. Am. Chem. Soc. 1992, 114, 10834.

[3] Vehlow K., Maechling S., Köhler K., Blechert S., J. Organomet.Chem. 2006, 691, 5267.

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Tandem Ru-catalyzed Isomerization/C-H activation/C-C coupling reaction

Agnieszka Bartoszewicz and Belén Martín-Matute*

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden

The search for the most atom-economical ways to form highly complex products is a matter of increasing importance among industrial and academic research groups. One way to fulfil this goal is to develop new tandem processes.

We envisioned that it is possible to combine the transformation of allylic alcohols into ketones with selective C-H activation process, and both processes could be catalyzed by the same ruthenium complex (Figure 1).[1] A number of Ru complexes, phosphine ligands and additives have been evaluated in order to establish optimal conditions. It was found that a stable ruthenium catalyst precursor - Ru(PPh3)3Cl2, together with PtBu3 and HCOONa secure efficient tandem transformation. Using the developed procedure, variety of ortho alkylated ketones have been obtained in excellent yields and short reaction times. Moreover, also homoallylic alcohols can be employed as starting materials.

The necessity of hydride donor (HCOONa) presence and the possibility of double bond migration over more than two bonds, suggest involvement of Ru hydrides in the isomerization mechanism. Indeed, mechanistic investigations, including reactions with deuterium labelled substrates, supported such mechanistic pathway.

[Ru]O

H

OH

O

O

R

Risomerization

C-H activationC-C bondf ormation

[Ru]

one-pot tandem reaction

H

Figure 1. Tandem Ru-catalysed isomerisation/C-H activation/C-C bond formation References [1] Bartoszewicz, A.; Martín-Matute, B. Org. Lett. 2009, 11, 1749–1752.

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First Heterogeneous Larock Synthesis of Indoles: Benefits of Using this New Heterogeneous Catalytic System

Nelly Bataila,b, Anissa Bendjerioub, Véronique Dufaudb, Laurent Djakovitcha* a Université de Lyon, CNRS, UMR 5256, IRCELYON, Institut de Recherches sur la Catalyse et

l’Environnement de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne, France b Laboratoire de Chimie, UMR 5182, ENS Lyon-CNRS, 46 Allée d'Italie, Lyon Cedex 07, F-69364

The growing interest in indole structures during the last 100 years results from the presence of this nucleus as a substructure in many bioactive natural compounds. This stimulated the research to obtain this indole moiety that resulted today in several useful syntheses. 1-3

Among them, the Pd-catalysed annulation of 2-iodoanilines with disubstituted alkynes, knows as the Larock heteroannulation,4 is probably the most efficient procedure to achieved in a single step the synthesis of 2,3-disubstituted indoles.

NH

R2

R1RR

I

NH2

+

R2

R1

Pd catalyst

However, the drawbacks of this methodology results from the exclusive use of homogeneous catalysts made from soluble metal precursors and the use of ligands and salts. This is linked with difficulty of separation and non-recyclability of the costly catalytic system. In addition, this can led to relatively high Pd contamination of the final product that is non-compatible in health applications.

For these reasons and for economic and environmental considerations, we developed the first ligand and salt free heterogeneous Larock synthesis.

Different commercially available or homemade catalysts (Pd/NaY, Pd/SBA-15) were evaluated after simplifying the conditions in homogeneous phase.

Generally good to excellent yields were achieved.

All results will be presented and discussed in details giving clearly the scopes and limitations of this new procedure.

1 Gribble, G. W., J. Chem. Soc., Perkin Trans. 1, 2000, 1045. 2 Sundberg, R. J., Indoles. Academic Press: London, 1996. 3 Zeni, G.; Larock, R. C., Chem. Rev., 2006, 106, 4644. 4 Larock, R. C.; Yum, E. K., J. Am. Chem. Soc., 1991, 113, 6689.

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Anion Effects on the Growth of Ruthenium Nanoparticles in Ionic Liquids

Markus Berger, Nicola Taccardi, Andreas Bösmann, Erdmann Spiecker* and Peter Wasserscheid

Institute of Chemical Reaction Engineering, University of Erlangen-Nuremberg, Egerlandstr. 3, 91058 Erlangen,

Germany * Institute of Microcharacterization, University of Erlangen-Nuremberg, Cauerstr. 6, D-91058 Erlangen

[email protected]

In recent years, the interest in catalysis promoted by metal nanoparticles (NP) is increasing. Ionic liquids are a unique reaction media and are often reported as electrosteric stabilizers for nanosized catalysts1. Ionic liquids can form a charged double layer around the NPs with the anion closer to the particle surface and the effect of various anions on the growth of gold and

copper particles has been reported2. Our poster reports the formation and growth of ruthenium nanoparticles in various imidazolium based ionic liquids. The ruthenium nanoparticles were synthesized by thermal decomposition of Ru3(CO)12 or by reduction of ruthenium precursors. Typically, the nanoparticles have not been isolated from the ionic liquid and have been handled “in-situ” or in diluted solutions of the ionic liquid. Dynamic light scattering (DLS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were applied for the estimation of the particle sizes. Fig: 1 Agglomerated ruthenium nanoparticles in

[EMIM]OTf

The anions of the ionic liquids have a strong influence on formation of particles. In some ionic liquids, e.g. [EMIM][OAc], the formation of nanoparticles is completely suppressed and no NPs are found. References [1] a) D. Astruc, F. Lu and J.R. Aranzaes, Angewandte Chemie International Edition, 2005, 44, 7852-7872;

b) J. Kraemer, E. Redel, R. Thomann and C. Janiak, Organometallics, 2008, 27, 1976-1978; c) G. Viau et al., Chem. Mater., 2003, 15, 486-494; d) E.T. Silveira et al., Chemistry - A European Journal, 2004, 10, 3734-3740.

[2] a) L. Ren, L. Meng, Q. Lu, Z. Fei, P.J. Dyson, Journal of Colloid and Interface Science, 2008, 323, 260-266; b) A. Filankembo, S. Giorgio, I. Lisiecki, M.P. Pileni, Journal of Physical Chemistry B, 2003, 107, 7492-7500.

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Application of Chiral Supramolecular Monodentate Ligands in the Asymmetric Hydroformylation of Internal Alkenes

Rosalba Bellini, Guillaume Berthon-Gelloz,* and Joost N.H.Reek*

Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, HIMS, Nieuwe Achtergracht 166, 1018 VW Amsterdam, Netherlands

*Email: [email protected], [email protected]

Although monodentate chiral ligands (P-stereogenic), were the first class of ligands used in asymmetric homogeneous catalysis, they have since been replaced by rigid bidentate ligands. However, there are a number of asymmetric transformations which would require only a monodentate and monoligated ligand to the transition metal (TM) catalyzed to achieve useful activities (e.g. Pd- and Pt- catalyzed hydrosilylation, Au and Ag catalysis). This area of catalysis has been neglected in part due to the difficulty of crafting an effective chiral environment around a TM with a monodentate and monoligated ligand.1

Inspired by recent reports of high asymmetric induction using bulky monodentate ligands

in Ir-catalyzed hydrogenation2 we set out to investigate the potential of creating bulky chiral ligands through supramolecular metal ligands interactions (Py-[Zn]).3 The extra bulk of the ligand created by the supramolecular interaction will only enable monoligation to the metal center.

O

OP NMe2

N

N

[Rh]

O

OP NMe2

N

N

[Rh]

Monodentate AND monoligated to TMs

Zn

Zn Zn

Zn

M

Zn

Zn

Chiral monodentate

backbone

"Amplification" of chirality through supramolecular interaction

Concept: Targeted ligands:

In this poster we will present the synthesis of H8-binol-based pyridine-containing ligands,

their coordination chemistry with Rh(I) and cataysis results in the asymmetric Rh-catalyzed hydroformylation of unactivated internal alkene.

1 F. Lagasse, H. B. Kagan, Chem. Pharm. Bull. 2000, 48, 315. 2 a) F. Giacomina, A. Meetsma, L. Panella, L. Lefort, A. H. M. de Vries, J. G. de Vries, Angew. Chem. Int. Ed. 2007, 46, 1497. b) Giulia

Erre, K. Junge, S. Enthaler, D. Addis, D. Michalik, A. Spannenberg, M. Beller, Chem. Asian J. 2008, 3, 887. 3 A. W. Kleij, J. N. H. Reek, Chem. Eur. J. 2006, 12, 4219

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Efficient enantioselective synthesis of β-aminoalcohols catalysed by samarium iodobinaphtolate

BEZZENINE, Sophie; MARTIN, Myriam; COLLIN, Jacqueline

Laboratoire de Catalyse Moléculaire, UMR 8182, Université Paris Sud, 91405 Orsay, France

A new family of chiral lanthanides complexes have been developed in our laboratory. Lanthanide iodo binaphtolates are very efficient enantioselective Lewis acid type catalysts for iminoaldolisation and aza-Michael reactions1, 2. The synthesis of enantioenriched aminoalcohols is an highly important topic for chemists since these molecules are widely employed as chiral auxiliaries, ligands or building blocks for the design of sophisticated molecules. Different synthetic routes have been reported for their preparation, yet new methods following green chemistry criteria are to be developed. We report here that samarium iodo binaphtolate catalyzes, in mild conditions, enantioselective ring opening of cyclic meso-epoxides by various aromatic amines producing β-amino alcohols with high enantiomeric excesses up to 93%3. In order to study synthetic applications, we have now extended these reactions to meso-epoxides including an heterocycle and new β-amino alcohols have been isolated with enantiomeric excesses up to 70%4. This method follows green chemistry criteria such as atom economy and/or catalytic reactions and the use of non toxic lanthanides.

X O ArNH2 X

OH

NHAr

+10% cat. I, CH2Cl2, MS 4A

18h.

X = CH2, CH2-CH2, CH=CH, O, N-R ee = 70 - 93 %

OO

Sm

(THF)

I

Cat.I =

Non linear effects have been studied and an amplification was observed in the case of the ring opening of 2,5-dihydrofuran oxide by p-anisidine. 1. Jaber, N.; Carrée, F.; Fiaud, J.-C.; Collin J. Tetrahedron: Asymmetry 2003, 14, 2067. 2. Reboule, I.; Gil, R. ; Collin, J. Tetrahedron: Asymmetry 2005, 16, 3881. 3. Carré, F. ; Gil, R. ; Collin, J. Org. Lett., 2005, 7, 1023. 4. Martin, M.; Bezzenine-Lafollée, S.; Gil, R.; Collin J. Tetrahedron: Asymmetry 2007, 18, 2598.

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Transfer Hydrogenation of Carbonyl Compounds over Heterogenized Wilkinson’s Catalyst

Krisztián Bogár,a Patrik Krumlinde,b Jan-E. Bäckvall*b aAstraZeneca R&D, Södertälje, SE-151 85, Sweden

bDepartment of Organic Chemistry, Stockholm University, Stockholm, SE-106 91 Sweden email: [email protected]

Combining the advantages of homogeneous and heterogeneous catalysis is possible by heterogenization of homogeneous transition metal complexes based on a grafting/anchoring technique. RhCl(PPh3)3 complex immobilized onto common silica showed high activity and selectivity in trasfer hydrogenation reactions of different carbonyl compounds in wet isopropanol in the presence of a mild base. Reactions conducted at reflux point of isopropanol afforded the corresponding alcohols in high yields in short reaction times. The heterogeneous feature of the catalyst allows easy recovery and efficient reuse in the same reaction up to five times without loss of catalytic activity.

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Pd mediates catalytic tandem β-boration / cross-coupling reaction of α,β-unsaturated carbonyl compounds

A. Bonet, Mª A. Ubeda, E. Fernández

Dept. de Química Inorganica, Universitat Rovira i Virgili, c/ Marcel.li Domingo s/n, 43007 Tarragona, Spain. e-mail: [email protected]

In the course of the development of catalytic diboration of alkenes [1], the metal-mediated 1,4-addition reaction of diboron reagents to electron deficient olefins ranks as the most convenient approach for the preparation of β-boryl carbonyl compounds [2], highlighting the recent approaches towards the asymmetric version, [3].

Taking into account our recent experience in β-boration of α,β-unsaturated aldehydes [4] and the potential palladium mediated tandem diboration of alkenes and alkynes followed by Suzuki reactions [5], we became motivated to establish a general methodology for Pd catalyzing β-boration of α,β-unsaturated compounds followed by a palladium arylation pathway. Special emphasis has been devoted towards the asymmetric induction by chiral ligands on the β-boration of the α,β-unsaturated substrates.

R1 R2

O Mt

R1 R2

OO

BO

BO

BO

O

O

ArXR1 R2

OAr

Additive

* *

[1] a) I. Beletskaya, C. Morgen, Chem. Rev., 2006, 106, 2320. b) T. Ishiyama, N. Miyaura, Chem. Rec., 2004, 3, 271. c) T. B. Marder, N. C. Norman, Top. Catal. 1998, 5, 62. [2] a) T. B. Marder, Organomet. Chem. 2008, 34, 46; b) V. Lillo, A. Bonet, E. Fernández Dalton Trans. 2009, 2899. [3] a) S. Mun, J.-E Lee, J. Yun, Org. Lett., 2006, 8, 4887; b) J.-E Lee, J. Yun, Angew. Chem. Int. Ed.., 2007, 47, 145; c) V. Lillo, A. Prieto, A. Bonet, M.M. Diaz-Requejo, J.Ramírez, P.J. Pérez, E. Fernández Organomet. 2009, 28, 659 [4] a) A. Bonet, V. Lillo, J. Ramírez, M. M. Díaz-Requejo, E. Fernandez Org. Biomol. Chem. 2009, 7, 1533. [5] D. Penno, V. Lillo, I. O. Koshevoy, M. Sanáu, M. A. Ubeda, P. Lahuerta, E. Fernández Chem. Eur. J., 2008, 14, 10648.

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Functionalization of the Internal Surface of UiO-66: an ultrastable Zr-MOF

Silvia Bordiga1, Sachin Chavan1, Elena Groppo1, Francesca Bonino1, Carlo Lamberti1, Cherif Larabi2, Elsje Alessandra Quadrelli 2

Karl Petter Lillerud3, Merete h. Nilsen3 and Søren Jakobsen3 1Department of Chemistry IFM, NIS Centre of Excellence, Centro di Riferimento, University of Torino, Via

Giuria 7, I-10125 Torino Italy. 2Laboratoire de Chimie Organométallique de Surface, Université de Lyon, UMR5265 “LC2P2”, CNRS UCBL1

CPE, 43 Boulevard du 11 Novembre 1918, BP2077, F-69616 Villeurbanne Cedex, France, 3Department of Chemistry, University of Oslo, P.O. Box 1033, N-0315 Oslo, Norway,

Metal Organic Frameworks (MOFs) provided a break-through in the area of porous materials, with their potentially unlimited pore sizes and surface areas. However, MOFs have one major dis-advantage in respect to other porous crystals (such as zeolites): their weak stability. New MOFs appear at a high pace, but the appearances of new stable inorganic building bricks are rare. Here we present a new zirconium based building brick that allows the synthesis of high surface area MOFs with high stability, allowing further functionalization [1–3]. UiO-66 has been used as starting point to obtain new materials encapsulating a large variety of species that can attract

interest in catalysis and in photocatalysis. The first new material has been obtained incorporating an amine group into the structure by the use of 2-aminoterephthalic acid during synthesis, thereby getting the MOF UiO-66-NH2 with the same morphology as UiO-66.

Another possibility exploits the use of a volatile organometallic complex to functionalize the benzene ring. In this way, starting from Cr(CO)6, Bz-Cr(CO)3 has been obtained. In this case it has been observed the possibility to photoactivate the system and exchange one of the CO ligand with nitrogen. This observation could open new perspective to combine photocatalysis and MOFs.

NN22

hhνν

A third way explored was to consider the possibility to use isolated hydroxyls to anchor new species. In fact it has been shown that it is possible to eliminate all the encapsulated solvent molecules but keeping, for each inorganic unit, four isolated hydroxyls groups that can graph species interesting as catalytic centers, such as metal nano-particles and-or oxidic entrapped nanoclusters . The work has been developed within IDECAT NoE.

1) Eddaoudi, M. ; Moler, D. B. ; Li, H. ; Chen, B. ; Reineke, T. M. ; O'Keeffe M. ; Yaghi, O. M., Acc. Chem. Res., 2001, 34, 319; 32, 276; Férey, G.; Mellot-Draznieks, C. ; Serre, C. ; Millange, F., Acc. Chem. Res., 2005, 38, 217. 2) Cavka, J, H.:Jakobsen, S. ; Olsbye, U. ; Guillou, N. ; Lamberti, C. ; Bordiga, S. ; Lillerud, K. L., J. Am. Chem. Soc., 2008, 130, 13850. 3) Arstad, B ; Fjellvåg, H ; Konghaug, K. O. ;; Swang, O.; Blom, R. ; Adsorption, 2008, 14, 755-762, Gascon, J ; Aktay, U ; Hernandez-Alonso, M. D. ; van Klink, G. P. M. ; Kapteijn, F ; J. Catal., 2009, 261, 75-87

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Synthesis and characterization of an hybrid material of fluorovanadoaluminophosphate type, templated by

1,3-diaminopropane

Bouzid BOUDJRIBA

Cité Ali Khoudja, Réghaia 16112 Alger, ALGERIE *Laboratoire de Chimie Physique des Matériaux Inorganiques. Faculté de chimie, U.S.T.H.B.

BP 32 el-alia, Alger, Algérie

A vanadoaluminophosphate has been hydro thermally synthesized at 180°C, under Autogeneous pressure in the presence of fluoride anions and diaminopropane (D.A.P) as structuring agent. The VAPO-DAP material was characterized by: Powder X ray diffraction, FT-IR, S.E.M., Chemical and thermal analyses and NMR spectroscopy (27Al, 31P).The Following empirical formula agrees with the results of the characterization: VAPO-DAP = [Al5 P7 V0.4 F2 O26] [ H3N (CH2)3 NH3]

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Bulky Iminophosphanamide Complexes of Nickel and Iron

Kathrin D. Brandt, Igor V. Shishkov, Frank Rominger and Peter Hofmann*

Organisch-Chemisches Institut, Universität Heidelberg INF 270, D-69120 Heidelberg, Germany

*[email protected]

Iminophosphanamides can function as useful anionic spectator ligands in late transition metal chemistry and catalysis. Various copper(I) carbene complexes bearing the deprotonated electron-rich, sterically demanding 1 could be isolated and allowed a comprehensive study of their electronic structures, geometries and reactivity.[i] Recently, COLLINS et al. have reported on an alkyl nickel iminophosphonamide complex, presumably the active catalyst in ethylene polymerization.[ii]

We present novel nickel and iron complexes based on iminophosphanamide 1. The anionic ligand can be generated by in situ deprotonation of 1 with KH or n-BuLi. In the presence of metal precursors FeBr2 and NiBr2 the monomeric iron(III) complex 3 and the dinuclear, halide-bridged nickel(II) complex 2 are obtained. Both are paramagnetic species showing tetrahedral metal configurations in the solid state (X-ray).[iii]

P

NH

N

tBu

tBu

SiMe3

SiMe3

1

1. KH, DME2. NiBr2, DME,85 °C, 12 h

P

N

N

SiMe3

SiMe3

Ni

Br

Ni

Br

N

P

N

tBu tBu

tBu tBu

SiMe3

SiMe3

2

1. KH, DME2. FeBr2, DME,85 °C, 12 h

P

N

N

SiMe3

SiMe3

Fe

Br

Br

tBu

tBu

3 Compounds 2 and 3 can serve as convenient starting materials for inter alia the corresponding η3-allyl and η3-benzyl complexes 4 (X-ray) and 5. Due to their low toxicity and low prices such iron and nickel complexes and their congeners should open interesting perspectives for the polymerization and/or copolymerization of olefins. Increasing attention is also being paid to their general performance and applicability in other catalytic reactions. Synthetic, structural, quantum chemical, and catalytic studies are under way.

[i] a) B. F. Straub, P. Hofmann, Angew. Chem. 2001, 113, 1328; Angew. Chem., Int. Ed. 2001, 40, 1288. b) I. V. Shishkov, F.

Rominger, P. Hofmann, Organometallics 2009, 28, 1049. c) P. Hofmann, I. V. Shishkov, F. Rominger, Inorg. Chem., 2008, 47, 11755.

[ii] a) R. L. Stapleton, J. Chai, N. J. Taylor, S. Collins, Organometallics 2006, 25, 2514. b) S. Collins, T. Ziegler, Organometallics 2007, 26, 6612.

[iii] The synthesis of 2 has been described earlier: R. Boese, M. Düppmann, W. Kuchen, W. Peters, Z. Anorg. Allg. Chem. 1998, 624, 837.

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mailto:*[email protected]

Highly selective Ru-pseudo-dipeptide catalyzed asymmetric transfer hydrogenation of ketones

Elina Buitrago, Jenny Wettergren, Per Ryberg and Hans Adolfsson*

Department of Organic Chemistry, Stockholm University, Arrhenius laboratory, SE-106 91 Stockholm, Sweden, Fax: 0046-(0)8-

Asymmetric transfer hydrogenation (ATH) of ketones is a simple method for producing enantiomerically enriched secondary alcohol. The transformation is usually performed with a chiral ligand coordinated to a transition metal. We have developed a class of modular pseudo-dipeptide ligands that are easily prepared from of N-Boc protected α-amino acids and amino alcohols. Ru-arene complexes with the pseudo-dipeptide ligand demonstrated high catalytic activity and selectivity in the ATH of aromatic ketones.1

Studies were performed on the catalytic system where both the addition of lithium chloride and of THF as a co-solvent showed positive effects on the reaction outcome. The presence of lithium chloride enhances both the selectivity and the rate of the reaction and performing the reaction in a mixture of propan-2-ol and THF turned out to be most beneficial. These optimized conditions were used in the ATH protocol with excellent results. Both electron rich and electron poor aromatic ketones are readily reduced to the corresponding secondary alcohols in short reaction time. The catalyst loading is 0.5 mol% and the ee’s are ecxellent in all cases, up to 99%.2

The applicability of the method has also been examined in the synthesis of some known, biologically active compounds.

1 Bøgevig, A; Pastor, I; Adolfsson, H; Chem. Eur. J., 2004, 10, 294 2 Wettergren, J; Buitrago, E; Ryberg, P; Adolfsson, H Chem. Eur. J., 2009,15, Early View

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Ionic π-acidic-ligands in Pd(0) catalysed Hiyama cross-coupling

Patrick S. Bäuerleina,b, John M. Slatterya, Ian J.S. Fairlamba, Adam F. Leea, Robert Thatchera, Christian Müllerb, Dieter Vogtb and Adrian Whitwooda

a) Department of Chemistry, University of York, Heslington, York, YO10 5DD, UK; Tel. (IJSF): +44 1904 434091; Tel. (JMS): +44 1904 432610; E-mail: [email protected] and [email protected]

b) Eindhoven University of Technology, Schuit Institute of Catalysis, Laboratory of Homogeneous Catalysis, Den Dolech 2, 5600 MB Eindhoven, NL; Tel.:+31 40 247 2483 ; E-mail:[email protected]

Palladium catalysed cross-coupling reactions (scheme 1) are powerful tools for forming carbon-carbon bonds in target orientated synthesis.[1,2] These reactions are normally carried out in standard solvents such as methanol or THF. Moreover, tuneable alkene-ligands are frequently used to stabilise the palladium nanoparticles. However, a major drawback of these systems is the product purification, as product and ligand separation is delicate due to similar polarities. This problem has been highlighted by Denmark et al. in an elegant and comprehensive study for various alkene ligands.[3]

O

O

O

Si(OEt)3

[Pd], alkene, F-source

Scheme 1: left: Hiyama reaction, right: ORTEP representation of an ionic alkene-ligand

To address this key problem we focused on the immobilisation of the catalyst in the reaction medium, an ionic liquid (IL), with subsequent extraction of the product under biphasic IL/solvent conditions. This procedure has already been proven useful e.g. in hydroaminomethylation reactions carried out in ILs.[4]

We have synthesised ligands that differ completely in their solubility from commonly used alkene ligands.[5] We achieved this by introducing cationic groups to a range of chalcone ligands rendering them insoluble in apolar solvents but soluble in ILs. In this way it is possible to extract the pure product from an IL reaction system without removing the ligand. Furthermore, this new class of ligands is interesting in terms of their special electronic properties, which might have an impact on the catalytic activity of the Pd-species. Additionally the interaction with the counter ion might have a pronounced effect on the reaction on changing from a strongly coordinating anion to a weakly coordinating anion.

We report here on the preparation of novel Pd-alkene catalysts and their application in cross-coupling reactions. Results show that eficient extraction of the product from the reaction mixture is possible without extracting the ligand of the Pd-complexes.

[1] Fairlamb, I.J.S.; Kapdi, A.R.; Lee, A.F., Org. Lett., 24, (2004), 4435. [2] Fairlamb, I.J.S.; Kapdi, A.R.; Lee. A.F.; McGlacken, G.P.; Weissburger, F.; de Vries, A.H.M.; Schmieder

van-de Vondervoort, L., Chem. Eur. J., 12, (2006), 8750. [3] Denmark, S.E.; Werner, N.S., J. Am. Chem. Soc., 130, (2008), 16382. [4] Hamers, B.; Bäuerlein, P.S.; Müller, C.; Vogt, D., Adv. Synth. Catal., 350, (2008), 332. [5] Bäuerlein, P.S.; Fairlamb, I.J.S.; Lee, A.F.; Müller, C.; Slattery, J.M.; Thatcher, R.; Vogt, D.; Whitwood,

A., Chem. Commun., submitted.

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Efficient hydrogenation of alkenes using highly active and reusable immobilised Ru complexes through a phosphamide bond

on AlPO4-Sepiolite

Juan M. Campeloa*, Felipa M. Bautistaa, Verónica Caballeroa, Diego Lunaa, Rafael Luquea, Jose M. Marinasa, Antonio A. Romeroa, Jose M. Hidalgob, Anastacia Macarioc, Girolamo

Giordanoc aDepartamento de Química Orgánica, Universidad de Córdoba, Campus de Rabanales, Edificio. Marie Curie,

E-14014 Córdoba, Spain. bSeneca Green Catalyst, S.L. Campus de Rabanales, 14014-Córdoba, Spain.

cDip. Ing. Chim. & Mat., Università della Calabria, I-870366 Rende (CS), Italy. *Fax: (+34)957212066, E-mail: [email protected]

This study shows a methodology that allows the use of any inorganic solid to support ruthenium complexes, where the complex is anchored to the support through a phosphamide bond that is comparatively much more stable than the conventional organosilane link described to obtain immobilised complexes on inorganic supports. Our protocol provides many advantages compared to any reported methodologies including minimum (or no) interaction with solvents or reagents under our employed conditions. This novel methodology has been developed to achieve an hybrid organic-inorganic bond for the covalent immobilization of the ruthenium complexes: [RuII(bpea){(S)(-)(BINAP)}Cl](BF4) and [RuII(bpea)(DPPE)Cl](BF4) where bpea=N,N-bis-(2-pyridylmethyl)ethylamine, BINAP= 2,2’-bis(diphenylphosphino)-1,1’-binaphthyl and DPPE= 1,2-diphenylphosphineethane, [1-3]. Both has been covalently grafted on AlPO4-Sepiolite (Figure 1) and tested in the liquid phase enantioselective hydrogenation of several substrates exhibiting very good activities and excellent reusabilities.

Scheme1. General scheme for the covalent immobilization of homogeneous [RuII(bpea){(S)(-)(BINAP)}Cl](BF4) complex.

References [1] D. Luna, F.M. Bautista, A. Garcia, J.M. Campelo, J.M. Marinas, A.A. Romero, A. Llobet, I. Romero, I. Serrano, PCT WO 2004/096442, 2004. [2] F.M. Bautista, V. Caballero, J.M. Campelo, D. Luna, J.M. Marinas, A.A. Romero, I. Romero, I. Serrano, A. Llobet, Top. Catal. 2006, 40, 193-205. [3] I. Serrano, M. Rodriguez, I. Romero, A. Llobet, T. Parella, J.M. Campelo, D. Luna, J.M. Marinas, and J. Benet-Buchholz, Inorg. Chem. 45 (2006) 2644.

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Gold: towards understanding its activity in arabinose oxidation.

Betiana C. Campo, Bright T. Kusema, Andrey Simakov and Dmitry Yu. Murzin*

Laboratory of Industrial Chemistry and Reaction Engineering, Process Chemistry Centre, Åbo Akademi, Biskopsgatan 8, FI-20500 Åbo/Turku, Finland

Gold as a catalytic metal was widely studied during the last 25 years. Its application in different reactions has demonstrated that it is active when finely dispersed over different supports. One of these cases is the oxidation of sugars, where Pd is the catalyst most commonly applied due to its activity. However the main disadvantage of palladium is the deactivation due to the overoxidation of the surface under reaction conditions. On the contrary, gold catalysts are quite stable. The origin of this stability could be the surface state of the catalysts. Thus XPS was applied to the characterization of fresh and spent Au/CeO2 catalysts. The data included in this contribution are preliminar results of our study.

Catalysts were submitted to different treatments: (a) reduction in formaldehyde (room temperature, 24 h) (b), reduction under hydrogen flow (300°C/3h) and (c) calcination in oxygen (300°C/3h). The samples were evaluated in arabinose oxidation at 60°C and pH 8.

The spectra of the fresh catalysts allowed to confirm the presence of particles smaller than 2 nm, evidenced by a contribution placed at binding energy lower than the one correspondent to metallic gold. This fact is also a consequence of the metal-support interactions. The presence

of Auδ+ implies the stabilization of gold particles on the surface defects, mainly oxygen vacancies [1]. The catalysts submitted to treatment (b) exhibits a small percentage of Au3+(See Table 1).

0

0.02

0.04

0.06

0.08

0.1

0 50 100 150 200 250Time (min)

C (m

ol/l)

(a) Formaldehyde

(b) Hydrogen

(c) Oxygen

Figure 1: Concentration of arabinonic acid during arabinose oxidation (60°C, pH 8).

Regarding the arabinonic acid concentration, the catalysts treated in hydrogen and oxygen presented similar behaviour. On the other hand, the one treated in formaldehyde presented lower values. The explanation of this fact could be the state of gold surface. To obtain the highest conversion of arabinose to arabinonic acid in the shortest reaction time substantial amount of gold should be present as Auδ+.

Table 1: Atomic percentages of different gold species determinated by XPS:

Treatment (a) (b) (c)

Specie Auδ+ Au0 Auδ- Auδ+ Au0 Auδ- Auδ+ Au0 Auδ-

Fresh 8.2* 88.5 3.3 51.6 45.4 3.0 43.2 48.4 8.4

Spent 47.8 27.9 24.3 42.1 31.7 26.2 47.7 32.1 20.2

* The Binding Energy of this contribution corresponds to Au3+.

References [1] Q. Fu, H. Saltsburg, M. Flytzani-Stephanopoulos, Science 301 (2003) 935

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Fluorous-tagged Polyoxometalates in Fluorous Media as Catalysts for Selective Oxidations

Mauro Carraro, Martino Gardan, Andrea Sartorel, Gianfranco Scorrano, Marcella Bonchio

Department of Chemical Sciences - University of Padova and ITM-CNR - section of Padova Via Marzolo, 1, 35131 Padova, Italy. E-mail: [email protected]

The complementary assembly of organic moieties and inorganic polyoxometalates is a powerful strategy for the synthesis of hybrid materials and for the development of new catalytic systems.1 The preparation of fluorous-tagged polyoxotungstates, in particular, is a valuable tool to further tune their features, thus allowing their use as oxidation catalysts in fluorinated media.2 The use of perfluorinated phases as reaction media presents indeed some remarkable advantages, including their inertness to oxidation, the high solubility of dioxygen, and the fluorine-based effect in peroxide activation.3

The decatungstate polyanion (W10O32)4-, an efficient autooxidation photo-initiator under mild conditions of temperature and oxygen pressure, has been isolated in the presence of a fluorous-tagged tetraalkylammonium cation. The resulting fluorophilic salt {[CF3(CF2)7(CH2)3]3CH3N}4W10O32 (RfN4W10) can be used in fluorinated alcohols, while its heterogenization has been obtained by the incorporation in polymeric films of Hyflon. 4 The amphiphilic character of this polyanion seems to template, under humidity-controlled casting conditions, the formation of a micro-structured porous membrane of Hyflon, with a pattern of regular pores (1-2 μm) where the inorganic catalytic domains are faced along the pores sidewalls, as in a multi-channel microreactor.

RfN4W10/HyflonRfN4W10/Hyflon

λ > 345 nm p O2=1 atm T= 20°C

OOH

> 345 nm p O2=1 atm T= 20°C

OH O

+

OH O

+

OH O

+

λ > 345 nm p O2=1 atm T= 20°C

OOH

> 345 nm p O2=1 atm T= 20°C

OH O

+

OH O

+

OH O

+

Figure 1. SEM-BSE and AFM images of Hyflon embedding RfN4W10, used for ethylbenzene photooxidation, highlighting the occurrence of catalytic pores. The resulting catalytic system has been used under irradiation in a continuous flow Catalytic Membrane Reactor (CMR), to obtain the radical photooxygenation of ethylbenzene (Figure 1), in neat conditions, with Turnover Numbers (TON) higher than 1000. Reactivity data, including a comparison between homogeneous and heterogeneous catalysis, provide an evidence of the substrate transformation whitin the catalytic membrane microchannels. Finally, the efficient epoxidation of 1-alkenes with hydrogen peroxide, in the presence of fluorous-tagged polyoxotungstates, will also be presented. 1 Carraro, M.; Sandei, L.; Sartorel, A.; Scorrano, G.; Bonchio, M. Org.Lett. 2006, 8, 3671 2 S. P. de Visser, J. Kaneti, R. Neumann and S. Shaik, J. Org. Chem. 2003, 68, 2903. 3 a) J.P. Bégué, D. Bonnet-Delpon, B. Crousse Synlett, 2004, 18; b) A. Berkessel, J. A. Adrio Adv. Synth. Catal. 2004, 346, 275. 4 M. Carraro, M. Gardan, G. Scorrano, E. Drioli, E. Fontananova, M. Bonchio, Chem. Commun., 2006, 43, 4533

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Preparation of single-site silica supported nickel catalysts for the polymerization of olefins or dienes

Aimery de Mallmann, Mostafa Taoufik, Nicolas Merle and Jean-Marie Basset

UMR5265, LCOMS, CNRS - CPE Lyon, Villeurbanne, F-69616 France

A common approach to develop catalysts for slurry or gas-phase polymerization processes is to support on a solid an efficient molecular complex used in homogeneous catalysis processes. In this study, different strategies were foreseen in order to obtain silica supported cationic Ni(II) organometallic fragments, via surface organometallic chemistry, from the grafting of a molecular complex.

Aryl ortho disubstituted α-diimine nickel(II) alkyl complexes are known to show remarkably high activities in the polymerization of ethylene, in combination with different co-catalysts.1 For 1,3 butadiene polymerization in homogeneous catalysis processes, cationic "ligand-free" nickel(II) allyl complexes are the most reactive identified nickel catalysts and yield polybutadiene with high degrees of cis-1,4 enchainment.2, 3 Oxide supported analogs of these molecular alkyl and allyl complexes were then targeted. Supported cationic complexes can be obtained, either by the reaction of an adapted Lewis acid on a neutral supported complex or by the grafting reaction of a molecular complex on an oxide support which was first modified with a Lewis acid.

A nickel-alkyl silica supported complex was synthesized from the molecular complex [(α-diimine)Ni(CH2-SiMe3)2] (α-diimine = 2,6-iPr2C6H4–N=CMe–CMe=N–C6H4iPr2-2,6).4

NiPr

iPr

iPr

iPr NiNs

N

NsN

iPr

iPr

iPr

iPr NiNs

N

O

O

SiO

O

NiPr

iPr

iPr

iPr NiNs

N

OH

OO

SiO O

O

SiO

O

BF3

BF3

TMS

+

A well-defined nickel-allyl silica supported complex was similarly prepared from the bis methallyl complex, Ni[η3-CH2C(CH3)CH2]2. The grafting reactions were followed by IR and GC and the resulting surface complexes were characterized by chemical analysis, 1H and 13C solid-state NMR and EXAFS. These well-defined surface species have then been activated by gaseous BF3 in order to obtain cationic Ni(II) catalysts, active for gas phase ethylene or 1,3 butadiene polymerisations. Solvent-free polymerizations of ethylene or 1,3 butadiene with these catalysts and other supported nickel complexes have been studied under different conditions. The performances of these supported catalysts is discussed and compared to those of molecular complexes used in homogeneous catalysis processes

(1) Ittel, S. D.; Johnson, L. K.; Brookhart, M., Chem. Rev. 2000, 100, 1169-1203. (2) Tobisch, S.; Taube, R. Organometallics, 1999, 18, 5204-5218. (3) O’Connor, A. R.; White, P. S.; Brookhart, M. J. Am. Chem. Soc. 2007, 129, 4142-4143. (4) Dorcier, A.; Merle, N.; Taoufik, M.; Bayard, F.; Lucas, C.; De Mallmann, A.; Basset, J. M. Organometallics, 2009, 28, 2173-2178.

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Towards Dynamic Kinetic Resolution of Axially Chiral Allenes

Jan Deska and Jan-Erling Bäckvall*

Department of Organic Chemistry, Arrheniuslaboratoriet, Stockholm University SE-106 91 Stockholm, Sweden

The significance of allenes as building blocks in organic synthesis has dramatically increased over the past decade, leading to a rising demand in efficient methods for the preparation of optically pure derivatives of this class of axially chiral compounds. Therefore a novel, highly enantioselective, biocatalytic process for the kinetic resolution of primary allenic alcohols using Porcine pancreatic lipase has been developed. Combining biocatalysis with a Palladium(II)-catalyzed racemization of the chirality axis in order to overcome the yield limitation of classical kinetic resolutions, progress towards a chemoenzymatic dynamic kinetic resolution could be made. Furthermore, the synthetic value of the optically active allenols derived from this resolution procedure is highlighted in the concise enantioselective total synthesis of the fungal metabolite (–)-striatisporolide A.

OH OH + O

Porcine pancreatic

lipase

vinyl butyrateiPr2O, rt

O

41% yield, 97% ee 58% yield, 70% ee

O O

HOOC

(-)-striatisporolide A

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105

A set-up for catalytic studies on supported mass selected clusters

Artur Domingues †, Giulia Di Domenicantonio †* and Varlei Rodrigues †

† GFNMN DFA- IFGW Universidade Estadual de Campinas, SP Brazil * Swiss National Science Foundation

The use of nanostructured materials in catalysis is nowadays a well established concept. The understanding of the microscopic mechanisms giving rise to the catalytic properties is however complicated by the intrinsic complexity of the system. A promising path to give further information on these phenomena is the study of model samples in which each determinant parameter can be controlled and varied independently. One class of heterogeneous catalyst that has attracted great attention in the last decade is constituted by metallic nanoparticles deposited on an oxide surface [1,2].

A new experimental set-up for the study of heterogeneous catalysis by cluster-based materials has been developed and is currently under testing. Cluster ions, pruduced in a magnetron sputtering source, are characterized by Time of Flight mass spectrometry and further directed to the deposition chamber. Here they can be mass selected and deposited onto a customized substrate or matrix. The substrate can be either commercial or deposited in situ; the gas composition of the atmosphere, as well as the sample temperatur can be controlled.

After deposition the sample can be moved in vacuum to the analysis chamber, equipped with microcalorimetry and temperature desorption spectroscopy tools, in order to perform in situ experiments.

[1] U.Heiz and E.L.Bullock, J.Mat.Chem 14 (2004), 564 [2] J.M.Antonietti et al., Rev.Sci.Instrum. 78 (2007), 54101

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An easily recyclable heterogenised Rh-catalyst for the asymmetric transfer hydrogenation of prochiral ketones

Jonas Dimrotha, Juliane Keilitzb, Rainer Haagb and Reinhard Schomäcker* a,*Technische Universität Berlin, Institut für Chemie, Straße des 17. Juni 124-128, 10623 Berlin, Germany

bFreie Universität Berlin, Institut für Chemie und Biochemie, Takustraße 3, 14195 Berlin, Germany

Asymmetric catalytic transfer hydrogenation (ATH) provides an attractive approach for the preparation of chiral building blocks such as secondary alcohols for pharmaceuticals and other biologically important substances. In terms of operational safety and simplicity, ATH has some advantages over the reduction with molecular hydrogen. By the use of hydrogen donors such as formates, secondary alcohols or the formic acid/triethylamine mixture, the risk associated with the use of hydrogen at high pressure can be avoided.

Good progress concerning the activity and enantioselectivity of homogeneously soluble transition metal complexes for use in ATH has been made in recent years. Water tolerant systems have been developed and some attempts have been made to adress the problem of reusability [1, 2]. Heterogenisation of catalytically active and highly stable complexes is one strategy to provide both, recyclable catalyst systems and less metal contamination of the products. Additionally, using water as solvent improves the environmental impact of the overall process.

Here we report the anchoring of a modified rhodium catalyst on polymeric membranes and particles as solid supports. The immobilised catalyst has been applied to the reduction of phenyl ketones in the water/sodium formate system. Good conversion rates and enantiomeric excesses up to 99 % have been achieved. The catalyst loaded supports could be reused several times without significant decrease of activity and selectivity. Due to the high catalyst stability to air, a simple recycling procedure was possible. The support was separated from the reaction mixture, washed with methanol, dried under reduced pressure and anew introduced into a flask.

Investigation regarding the conversion of different substrates and optimised reaction parameters is still under progress.

1. S. Gladiali, E. Alberico, Chem. Soc. Rev. 35, 226-236 (2006). 2. X. Wu, J. Xiao, Chem. Commun., 2449–2466 (2007).

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Fe-catalyzed Carbonylation: Selective and Efficient Synthesis of Succinimides

Katrin Marie Driller[a], Holger Klein[a], Ralf Jackstell[a], and Matthias Beller*[a]

[a] Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-5000.

The development of sustainable, more efficient and selective catalysis is a fundamental goal in chemistry. During the last decades, manifold transition-metal catalyzed reactions have been uncovered, which have significantly improved organic synthesis. Notably, most of the applications are based on complexes of precious metals such as palladium, rhodium, iridium, and ruthenium. The limited availability of these metals and their high price makes it highly desirable to search for more economical and environmentally friendly alternatives. Among the various bio-relevant metals especially iron is an attractive alternative, which offers significant advantages compared with precious metals. Iron is cheap, benign, readily available, and ecological friendly. Obviously, numerous iron salts and iron complexes are commercially accessible on a large scale or easy to synthesize.

In order to achieve catalytic carbonylations based on iron, we started to investigate the reaction of alkynes with carbon monoxide and different nucleophiles. Herein, we report the first iron-catalyzed synthesis of succinimides by carbonylation of different terminal and internal alkynes with ammonia or amines in good selectivity and high activity. This new catalytic reaction is based on the double carbonylation of alkynes and intramolecular nucleophilic attack.

R'

R''

CO, NH3

Fe-cat.NH

R'

R''

O

O

CO, H2NR'''

Fe-cat. NR'''R'

R''

O

OR'= H, alkyl, arylR''= alkyl, arylR'''= alkyl, aryl

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108

Mononuclear Ru complexes that promote light-driven water oxidation

Lele Duan, Yunhua Xu, Licheng Sun*

Department of Chemistry, School of Chemical Science and Engineering, Royal Institute of Technology (KTH), Stockholm, 10044, Sweden

Corresponding author’s e-mail: [email protected]

Water is oxidized by the oxygen-evolving complex (OEC) driven by light in Photosystem II (PSII), providing electrons and protons for chemical energy storage. Inspired by the function of OEC, tremendous efforts have been spending on the artificial photosynthesis system aiming at light-driven water splitting into molecular hydrogen and oxygen.[1-2] This approach is extremely important for the solar energy conversion into a fuel and the ultimate challenge in this approach is the catalytic water oxidation driven by visible light. To the best of our knowledge, only a couple of dimeric ruthenium complexes and CoSO4 were reported to promote photochemical water oxidation in homogeneous systems in the presence of photosensitizers Ru(II)(bpy)3

2+ and Ru(II)(4,4’-DCE-bpy)32+ (bpy = 2,2’-bipyridine; 4,4’-

DCE-bpy = 4,4’-dicarboxyethyl-2,2’-bipyridine) with E1/2(RuII/III) being 1.26 V and 1.4 V, respectively.[3-6]

Herein, we present a series of mononuclear ruthenium complexes Ru(bpda)(L)2 (bpda = 2,2´-bipyridine-6,6´-dicarboxylic acid, L = 4-bromopyridine, (1); pyridine, (2); 4-methylpyridine, (3); 4-methoxypyridine, (4); 4-(dimethylamino)pyridine, (5); pyridazine, (6)) that promote light-driven water oxidation in homogeneous systems. These molecular Ru complexes showed efficiently catalytic properties towards both chemically and photochemically driven water oxidation in homogeneous solution.

N NO

O OORu

N

Br

N

Br

N NO

O OORu

N

N

N NO

O OORu

N

Me

N

Me

N NO

O OORu

N

O

N

O

N NO

O OORu

N

N

N NO

O OORu

N N

N N

Me

Me N

NMe Me

MeMe1 2 3 4 5 6

Figure 1. Molecular structures of complexes 1-6.

References [1] R. Eisenberg, H. Gray, Inorg. Chem. 2008, 47, 1697. [2] L. Sun, L. Hammarström, B. Åkermark, S. Styring, Chem. Soc. Rev. 2001, 30, 36. [3] J. L. Cape, J. K. Hurst, J. Am. Chem. Soc. 2008, 130, 827. [4] P. Comte, M. K. Nazeeruddin, F. P. Rotzinger, A. J. Frank, M. Grätzel, J. Mol. Catal. 1989, 52, 63. [5] F. P. Rotzinger, S. Munavalli, P. Comte, J. K. Hurst, M. Graetzel, F. J. Pern, A. J. Frank, J. Am. Chem. Soc.

1987, 109, 6619. [6] A. Harriman, G. Porter, P. Walters, J. Chem. Soc., Faraday Trans. 2 1981, 77, 2373.

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Supported Ionic Liquid Phase Catalysis with Supercritical flow

Ruben Duque, Eva Öschner, Stephen P. Nolan, and David J. Cole-Hamilton

EaStCHEM, School fo Chemistry, University of St. Andrews, St. Andrews, Fife, KY16 9ST

The separation of catalysts from the solvent and reaction products remains one of the major disadvantages of homogeneous catalytic reactions, which are otherwise advantageous because of their high activity, tuneable selectivity and ease of study. In recent years a large number of different strategies has been employed to address this problem, ranging from the use of soluble and insoluble supports, sometimes with ultrafiltration, to the application of biphasic systems.1, 2 Ideally, the reactions would be carried out in continuous flow mode with the catalyst remaining in the reactor at all times, whilst the substrates and products flow over the catalyst. A variety continuous flow reactions has been proposed,3 but in this presentation we shall highlight the use of supported ionic liquid phase catalysts, over which the substrates a flow dissolved in supercritical carbon dioxide (scCO2). The products are also removed by the flowing scCO2 stream.4

The catalyst is supported within a thin film of an ionic liquid supported within the pores of a microporous silica. This catalyst is then placed in a tubular flow reactor, similar to that used for heterogeneous reactions. The use of pressurised CO2 as the transport medium offers certain advantages, including:

• A wider substrate selection than is possible for all gas-phase reactions;

• Lower solubility of the ionic liquid and the catalyst in the flowing phase than when using all liquid flow;

• Better transport of gases to the catalytic centres than for liquid flow

• Fast diffusion of all species to the catalytic centres

Potentially, these advantages allow for high reaction rates, high rates of transport of substrate over the catalyst and low leaching of both the catalyst and the ionic liquid.

scCO2

We shall describe work on various different reactions including metathesis (see Figure 1), as well as discussing the effects of different reactant parameters – pressure, flow rates etc. on the reaction activity and selectivity, as well as on the lifetime of the catalyst. 1. D. J. Cole-Hamilton, Science, 2003, 299, 1702. 2. D. J. Cole-Hamilton and R. P. Tooze, eds.,

Catalyst Separation, Recovery and Recycling; Chemistry and Process Design, Springer, Dordrecht, 2006.

3. D. J. Cole-Hamilton, T. E. Kunene and P. B. Webb, in Multiphase Homogeneous Catalysis, ed. B. Cornils, Wiley VCH, Weinheim, 2005, vol. 2, pp. 688.

4. U. Hintermair, G. Y. Zhao, C. C. Santini, M. J. Muldoon and D. J. Cole-Hamilton, Chem. Commun., 2007, 1462.

scCO2

Cat

Cat

IL

IL

CAT

IL

Figure 1 Schematic diagram of supported ionic liquid phase metathesis with supercritical flow

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110

Carbon Dioxide as a Building Block for Production of Polymers

Giulia Erre , Willy Offermans, Igor Busygin, Christoph Gürtler, Thomas E. Müller, Walter Leitner*

CAT Catalytic Center, ITMC, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany * Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 1, 52074

Aachen, Germany

Carbon dioxide is an attractive, low-cost and readily available C1 building block for chemical synthesis. Despite of its thermodynamic stability, many catalytic systems were reported for utilization of CO2 in the production of industrially interesting compounds and materials.1 In our laboratories, we investigate the copolymerization between epoxides and CO2. Products of this reaction are highly valuable polyethercarbonates, while cyclic carbonates are often formed as side-products.

Figure 1

The purpose of this work is to establish intrinsic and operational parameters for the copolymerization of carbon dioxide and epoxides. It requires a multidisciplinary approach and a contribution from different disciplines. One of our primary interests is in the use of combined theoretical and experimental techniques to understand the mechanism of elementary reactions over the active center, and to determine how the particular topology of a catalytic system is related to its function as a catalyst.

A promising approach to obtain highly active catalysts for the co-polymerization reaction of epoxides with CO2 is the optimization of homogeneous catalysts, based on Co, Zn, Al and Cr.2 Many reports have already been published which indicate the great potential of this type of reaction. The homogeneous system can be tuned easily to suppress the formation of cyclic products and provides a better molecular understanding of the reaction. It is our objective to attain a deeper understanding of the mechanistical pathway and in turn design a simple and inexpensive homogeneous system which could deliver high activity and selectivity.

Fig. 2: Model for the active site of Co(III)-salen complex, which is known as

homogeneous catalyst for the epoxide/CO2 copolymerization,.

1 Beckman, E. J. Science 1999, 283, 946-947 2 Coates, G. W.; Moore, R. D. Angew. Chem. Int. Ed. 2004, 43, 6618-6639

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Ethylene polymerization catalysed by titana-calixarene complexes

Espinas J.1,2; Darbost U.2; Duchamp C.2; Bayard F.1; Thivolle-Cazat J.1; Basset J.-M.1; Taoufik M. *1; Bonnamour, I. *2

1UMR 5265, LCOMS, CNRS-CPE Lyon, Villeurbanne, F-69616, France 2UMR 5246, ICBMS, Université Lyon 1, Villeurbanne, F-69622, France

In the last years many metal calixarenes complexes were synthesized, 1 but only in a few cases they were used as soluble Ziegler Natta catalysts to promote the polymerization of α-olefins. Ladipo and coworkers 2 first synthesized several titanium calixarenes complexes and used them as catalysts, in the presence of methylalumoxane (MAO), to promote the polymerization of ethylene. Recently, 1,3-dimethoxy-p-tBu-calix[4]arene titanium dichloride3 and 1,3-dipropoxy-calix[4]arene titanium dichloride4 were also reported for the same application. The activity of these systems1 calix-MAO is very low 80 Kg/mol.h.

These compounds could be considered similar to the titanium bis-aryloxide. In fact the calixarene ligands are coordinated to the metal by phenoxy oxygens on the positions 1 and 3 of the calixarene while the other two phenoxy oxygens are chemically protected.

X OOX

But tButButBu

Ti

ClCl

Tuning the coordination sphere of titanium complexes via the preparation of various calixarene ligands with different structural parameters in 1,2 and 1,3 positions can help to increase the activity in ethylene polymerization.

In this work, we wish to present the syntheses and full characterization (1H, 13C, NOESY, DEPT, HMBC NMR, elemental analysis and X-Ray structures) of various p-tBu-calix[4]arene titanium dichloride complexes with different substituents in 1,2- and 1,3 positions in order to test them in the presence of MAO (Methylalumoxane), as catalysts for ethylene polymerization, at different temperatures and pressures.

All the polymers obtained showed a high molecular weight and a narrow chain distribution indicative of a single site catalyst. The results also reveal an important effect of the pπ-dπ interactions between Titanium and oxygens of the calixarene on the stability of the active site and the catalytic activity.

(1) Wieser, C.; Dieleman, C. B.; Matt, D. Coord. Chem. Rev. 1997, 165, 93-161. (2) Ozerov, O. V.; Rath, N. P.; Ladipo, F. T. J. Organomet. Chem. 1999, 586, 223-233. (3) Capacchione, C.; Neri, P.; Proto, A. Inorg. Chem. Commun. 2003, 6, 339-342. (4) Frediani, M.; Semeril, D.; Comucci, A.; Bettucci, L.; Frediani, P.; Rosi, L.; Matt, D.; Toupet, L.; Kaminsky, W. Macromol. Chem. Phys. 2007, 208, 938-945.

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1H, 13C, 31P and 103Rh NMR studies and DFT calculations in homogenous hydrogenation of nitrogen-containing substrates: Study of diphosphine rhodium complexes and catalytic cycle.

Amandine Fabrello, Martine Urrutigoïty, Odile Dechy Cabaret, Philippe Kalck, Laurent Maron*, et Lionel Perrin*

Université de Toulouse, Laboratoire de Chimie de Coordination UPR8241, Equipe de Catalyse et Chimie Fine, composante ENSIACET - Institut National Polytechnique de Toulouse, 118, route de Narbonne, 31077 Toulouse

Cedex 04 (France) * Laboratoire de Physique et Chimie de Nano-Objets (UMR 5215), Département de Génie Physique

135 avenue de Rangueil, 31077 Toulouse Cedex 4 (France)

The mechanism of the catalytic hydrogenation of imines and functionalized enamines is currently the object of investigations. Halpern1 and Landis2 and later Imamoto3 demonstrated that two main pathways occur for the hydrogenation of enamides: the unsaturated way characterized by the substrate coordination previously to the oxidative addition of dihydrogen, and the dihydride pathway characterized by the initial coordination of dihydrogen.

All of these studies are based on two major techniques of investigations4: multi-nuclear and variable temperature NMR studies and DFT calculations. Due to significant improvements in calculation methods the globality of the system can be more and more taken into account (ligands, solvent) which makes DFT studies as much accurate and predictive. On the other hand, development of NMR and especially improvement in 2D analyses, flexibility of NMR probes as well as increasing of magnetic field allow to gain determining information.

To fully understand the mechanistic pathway of the hydrogenation of some unusual imines we have firstly studied the 1H, 13C, 31P as well as 103Rh NMR data of some [(Diphos)Rh(COD)]+

cationic rhodium complexes used in catalytic hydrogenation5. To compare the 103Rh chemical shift in different conditions of hydrogenation we have studied the influence of the solvent, the temperature, the counter-anion and of course the phosphorus ligand on the chemical shifts.

Then comparative studies have been done between two families of diphosphines based on DIOP and DUPHOS to understand the mechanistic pathway by NMR and by DFT calculations as well.

The purpose of this communication is to present how we can use a non classical used 103Rh chemical shift correlated to DFT theoretical calculations to characterize complexes and identify key intermediates of the catalytic cycle.

1 C. R. Landis, J. Halpern, J. Am. Chem. Soc., 1987, 109, 1746. 2 S. Felgus, C. R. Landis, J. Am. Chem. Soc., 2000, 122, 12714. 3 a) I.D. Griednev, T. Imamoto, Acc. Chem. Res., 2004, 37(9), 633-644; b) T. Imamoto, T. Itoh, K. Yoshida, I.D. Griednev, Chem. Asian J., 2008, 3, 1636 4 A. Fabrello, A. Bachelier, M. Urrutigoïty, and P. Kalck, Coord. Chem. Rev., submitted. 5 W. Leitner, M. Buhl, R. Fornika, C. Six, W. Baumann, E. Dinjus, M. Kessler, C. Krüger, and A. Rufińska, Organometallics 1999, 18, 1196-12060.

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Aminophosphine-based pincer complexes of palladium as highly efficient C-C cross coupling catalysts. PdIV intermediates and

palladium nanoparticles.

J. L. Bolliger, O. Blaque, C. M. Frech*

University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland

Palladium based pincer complexes belong to some of the most efficient Heck- and Suzuki- catalysts and continuously attract attention because of their unique balance between stability and reactivity.1 Although recent developments showed a considerable increase in activity of cross-coupling catalysts, a typical protocol for these reactions still requires prolonged reaction times and/or high catalyst loadings, referring to the need of more efficient systems. Since the nature of the active form of pincer catalysts of palladium (Pd0 vs PdIV) in the Heck reaction e.g. is still unclear in some of the applied systems,2 a catalyst was developed, which could support both, palladium nanoparticle formation as well as the formation of PdIV intermediates.

We present the synthesis and catalytic activity of aminophosphine-based pincer complexes of palladium with the general formula of [(C6H3-2,6-(XP(piperidinyl)2)2Pd(Cl)] (X = NH and O) in various C-C cross-coupling reactions. Investigations to get mechanistic insights are presented for each of the reaction.

X

X

P

P

Pd Cl

NR2NR2

NR2NR2

R = piperidyl, X = NH or O

[1] (a) Ohff, M.; Ohff, A.; van der Boom, M. E.; Milstein, D. J. Am. Chem. Soc. 1997, 119, 11687. (b) Morales-Morales, D.; Redon, R.; Yung, C.; Jensen, C. M. Chem. Commun. 2000, 1619.

[2] (a) Bedford, R. B., Chem. Commun. 2003, 1787. (b) Eberhard, Org. Lett., 2004, 2125.

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Heterogenization of enzymes by using natural phospholipids (lecithin) and lactose as templates and protecting agents

in sol-gel silica encapsulation

Anne Galarneau, Paco Laveille, Lai Truong Phuoc, Jullien Drone, Gilbert Renard, François Fajula

Institut Charles Gerhardt de Montpellier, UMR 5253 CNRS/UM2/ENSCM/UM1, ENSCM, 8 rue de l’Ecole Normale, 34296 Montpellier Cedex 5, France.

e-mail: [email protected]

The immobilization of enzymes in inorganic supports is expected to provide breakthroughs in the area of heterogeneous catalysis. Enzymes are outstanding catalysts with very high catalytic efficiency and very high specificity. However, they are barely used, because of their fragility. Appropriate immobilization helps to maintain their quaternary structure, to protect them against external environment (solvent, pH, temperature, inhibitors), to recover the products and to develop process in continuous flow.

We have developed a new way of enzyme encapsulation in sol-gel silica, by using natural surfactant (egg lecithin) and sugar (β-lactose) as enzyme protecting agents and as templates for structuring the porosity of silicas to add a porosity control to the classical sol-gel synthesis and to promote diffusivity inside the material to reach the maximum of enzymes and then to optimize the sol-gel encapsulation technique. Two kind of structures were identified in this new system by changing synthesis composition: Sponge Mesoporous Silica (SMS)1, which present an isotropic 3-dimensional structure with 5 nm pore size forming micronic spherical particles, and porous NanocaPsules of Silica (NPS) 2 of 7 nm resulting in a powder of aggregated nanoparticles. Different enzymes were encapsulated efficiently by these new routes with higher activities compared to classical sol-gel synthesis: very stable enzymes (lipase3,4, hemoglobin), very fragile enzyme (alcool dehydrogenase), polyenzymatic systems (Glucose Oxydase/Horse Radish Peroxidase)2 to generate in-situ H2O2 for oxidation reactions directly from molecular oxygen and compared to classical immobilization technics (different sol-gel, polymer grafting, adsorption on silica). Higher catalytic activity and specific activity were found for this new type of sol-gel encapsulation. Also a change in selectivity for lipase4 was observed maybe due to a slight change in enzyme conformation during encapsulation.

SMS and NPS route may constitute a new generation of very selective heterogeneous biocatalysts.

References: 1- A. Galarneau, G. Renard, M. Mureseanu, A. Tourrette, C. Biolley, M. Choi, R. Ryoo, F. Di Renzo, F. Fajula, Microporous Mesoporous Mater., 2007, 104 , 103. 2- A. Galarneau, L. Truong Phuoc, A. Falcimaigne, G. Renard, F. Fajula, Stud. Surf. Sci. Catal., 2007,165, 637. 3- M. Mureseanu, A. Galarneau, G. Renard, F. Fajula, Langmuir, 2005, 21, 4648. 4- A. Galarneau, M. Mureseanu, S. Atger, G. Renard, F. Fajula, New J. Chem., 2006, 30, 562.

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Synthesis of sterically hindered P-Stereogenic Phosphorous compounds

David Gatineau,† Laurent Giordano,† David Martin† and Gérard Buono*,†

*,†Université Paul Cézanne, Institut des Sciences Moléculaires de Marseille, ECM, CNRS, UMR6263, Av. Escadrille Normandie-Niémen, 13397 Marseille Cedex 20, France

Chiral organophosphorous compounds have been widely used in asymmetric catalysed transformations as chiral ligands and chiral catalysts.1 Phosphines bearing either axial or planar chirality on stereogenic carbon centers have been more commonly employed. In marked contrast only few P-stereogenic ligands have been studied due to the lack of versatile and efficient methodologies for their syntheses.2

In the past two decades the development of phosphine boranes chemistry afforded a popular access to P-chiral compounds but those methods are limited to not sterically hindered substituents. Recently phosphinous acid boranes have been used as key intermediates in the preparation of bulky tertiary and secondary phosphine boranes.3 Some enantiopure phosphinous acid-boranes are available, but only from racemic resolution. Two stereoselective syntheses are reported in the literature and none exceeds 73% of enantiomeric excess.4

Recently we developped an enantioselective synthesis of secondary phosphine oxides (SPOs) based on stereoselective substitution of (–)-menthyloxy group by alkyl or aryl lithium of (RP)-(–)-menthyl-hydrogenophenylphosphinate (Scheme 1).5 This approach can be adapted to the synthesis of phenylphosphinous acid-boranes (Scheme 1).6

OPO

HPh

POLi

RPh

2 RLi

H2O

1/ BH3.SMe2

2/ HCl

PO

HPh R

POH

RPhH3B

72 to 99% ee

Scheme 1

We report a simple route to various arylphosphinous acid-boranes and their use as precursors to form enantiomerically pure tertiary phosphine-boranes (scheme 2).

O

PO

HR1

POH

R2

R1H3B PBH3

HR2R1 R1 P

BH3R3

R2up to 99% ee

Scheme 2

1 a) Comprehensive Asymmetric Catalysis, ed. Jacobsen E. N., Pfaltz A. and Yamamoto H., Heidelberg, 1999; b) Catalytic Asymmetric Catalysis, ed. Ojima I., Wiley-VCH, New York, 2nd ed., 2000. 2 Grabulosa A., Granell J. And Muller G. Coord. Chem. Rev., 2007, 251, 25-90. 3 Stankevic M. and Pietrusiewic K. M. J. Org. Chem., 2007, 72, 816-822 4 Uziel J., Stephan M., Kaloum E. B., Genêt J. P. And Jugé S. Bull. Soc. Chim. Fr., 1997, 134, 379-389; Nagata K., Matsukawa S. and Imamoto T. J. Org. Chem., 2000, 65, 4185-4188 5 Leyris A., Bigeault J., Nuel D., Giordano L., Buono G. Tetrahedron Lett. 2007, 48, 5247-5250 6 Moraleda D., Gatineau D., Martin D., Giordano L., Buono G. Chem. Commun. 2008, 3031-3033

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A well-defined, silica-supported chiral Zn scaffold for enantioselective catalysis

Jérémy Ternel,1 Laurent Delevoye,1 Francine Agbossou,1 Régis M. Gauvin,1,* Thierry Roisnel,2 Christophe M. Thomas2,*

1 Unité de Catalyse et de Chimie du Solide UMR CNRS 8181, Ecole Nationale Supérieure de Chimie BP 90108, 59 652 Villeneuve d’Ascq Cedex (France)

2 Laboratoire Charles Friedel, UMR CNRS 7223, Ecole Nationale Supérieure de Chimie de Paris, 11 rue Pierre et Marie Curie 75005 Paris Cedex 5 (France)

Heterogenization of a chiral catalyst onto an inorganic support is an approach that is most often used in order to develop recyclable systems amenable to efficient metal and/or ligand recovery, and to design less environmentally-harmful processes.1 However, a significant impact on the catalyst’s performances follows its immobilization.

We describe here the synthesis of a new chiral bisalkyl zinc complex, Zn[(S,S)-iPr-pybox](Et)2, characterized by X-rays diffraction studies. Controlled grafting of this species onto highly dehydroxylated silica affords a hybrid material bearing chiral zinc centers singly bound to the inorganic support. Its full characterization has been performed, by elemental analyses, infrared spectroscopy and mono- and bidimensional, multinuclear high-field NMR (18.8T).

N

ON

NO

+ ZnEt2

OH

Si OOOSiO2

-C2H 6O

Si OOOSiO2

NN

O

O NZn

(S,S )- iPr-pyb ox

We probed the behavior of the molecular and supported zinc species in asymmetric benzaldehyde silylcyanation.2 Remarkably, under optimized conditions, the heterogeneous catalyst displays activity and selectivity superior to that its molecular counterpart: it affords the silylated mandelonitrile with up to 66% enantiomeric excess, compared to 18% for the homogeneous system. The ease of access to chiral supported zinc species makes this approach a promising entry into efficient heterogeneous asymmetric catalysis.

1) C. E. Song, S. Lee, Chem. Rev. 2002, 102, 3495. 2) M. North, D. L. Usanov, C. Young, Chem. Rev. 2008, 108, 5146.

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Immobilization of Ti-POSS species via covalent anchoring approach. Ti(IV) sites with a controlled chemical environment.

Elena Gavrilova1,2, Matteo Guidotti2, Rinaldo Psaro2, Laura Sordelli2, Chiara Bisio3, Fabio Carniato3, Leonardo Marchese3

1Dip. CIMA “L. Malatesta”, via Venezian 21, Milano, Italy 2 CNR-Istituto di Scienze e Tecnologie Molecolari, via Venezian 21, Milano, Italy;

[email protected] 3 Dip. di Scienze e Tecnologie Avanzate and Nano-SISTEMI Centre, Università del Piemonte Orientale, via

Bellini 25G, Alessandria, Italy

Polyhedral oligomeric silsesquioxanes (POSS) have polyhedral structures with different degrees of symmetry. Silicon atoms are in tetrahedral coordination at the corners of the cage, and each oxygen atom shares two Si atoms. Each silicon atom is bonded to one and a half oxygen (sesqui-) and to a hydrocarbon group (-ane). POSS-ligated titanium(IV) complexes have proven to be highly active for epoxidation of alkenes1. A direct anchoring, through covalent bonding of Ti-POSS cages onto silica materials of various morphology, was recently reported2. The possibility to establish a covalent bond between Ti-POSS and the support surface is necessary to obtain a heterogeneous catalyst with marked chemical stability. Thanks to the covalent anchoring of defined Ti-POSS species, it is also possible to obtain a controlled chemical environment and geometry of Ti(IV) sites. Spectroscopic evidences (DR-UV-Vis, FT-IR, EXAFS and XANES) show that most of the Ti-POSS anchored species are present as dinuclear moieties (Scheme 1). This implies that the dinuclear Ti-POSS structures are located outside the mesopores, on the external surface of the mesoporous silica, because the size of the mesopores cannot accommodate such bulk species. This hypothesis is confirmed by porosimetric and modelistic data (kinetic diameter of the dinuclear species larger than the diameter of mesopores).

Scheme 1

dinuclear Ti-POSS-TSIPI

TiTiO

O

RR

RR

R

R

R

R'

R'

Pri

iPr

To test and verify the activity and accessibility of Ti(IV) sites in all Ti-containing materials (Ti-POSS/SBA-15 and Ti-POSS/SiO2, Ti-POSS/nano-MCM-41), epoxidation reactions of limonene and α-pinene with TBHP as oxidant were performed. The anchored materials were compared to widely-studied titanium-containing heterogeneous catalysts obtained by grafting a similar loading of Ti(Cp)2Cl2 onto mesoporous silica supports. Anchored Ti-POSS-derived materials showed high activity in the epoxidation of limonene and α-pinene and the heterogeneous character was confirmed. In terms of selectivity, the anchored catalysts display different results with respect to those obtained by grafting Ti(Cp)2Cl2. This different catalytic behaviour is due to the dissimilar chemical surrounding of the Ti(IV) sites in the anchored and grafted materials. 1 K.Wada, T.Mitsudo, Catal. Surv. Asia 2005, 9, 229-241 2 F.Carniato, C.Bisio, E.Boccaleri, M.Guidotti, E.Gavrilova, L.Marchese, Chem. Eur. J. 2008, 14, 8098-8101

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Reaction sequence for hydrogenation of oximes to primary amines

Ewa Gebauer-Henke1), Yevgen Berezhanskyy1), Christoph Gürtler1), Marcel Liauw2), Walter Leitner2), Thomas E. Müller1)*

1) CAT Catalytic Center, ITMC, RWTH Aachen University, Worringerweg 1, 52074 Aachen, Germany 2) Institut für Technische and Makromolekulare Chemie, Technische Chemie und Petrolchemie, RWTH Aachen

University, Aachen, Germany

Amines represent an important class of compounds in chemistry and biology. Among all the variety of amines, primary amines are the most useful, but their selective synthesis is challenging due to their high reactivity. Transformation of carbonyl compounds via oximes is one of several possible ways for the synthesis of primary amines. This reaction is known to be very sensitive; chemical yield and selectivity strongly depend on substrate structure and on the catalytic system.

In this work, the hydrogenation of aldoximes (2-butyraldoxime, nonanal aldoxime, pivalaldoxime, cyclohexane aldoxime,) on different catalysts (Raney-Ni, Raney-Co, Ni-Cr/SiO2, Ni/Al2O3, Pd/C, Rh/C, Ru-Re/C) was studied to establish optimum reaction parameters.

Independently of the substrate the selectivity to the desired product strongly depended on the catalyst used. The highest selectivity and activity were obtained for nickel catalysts (both Raney-Ni and Ni-Cr/SiO2). Full conversion was achieved after 75 minutes and selectivity towards primary amine was higher than 95%. The best results were obtained for 10 wt.% catalyst for reaction temperature equal to 180°C. Under this conditions highest selectivity, shortest initial period of reaction and shortest reaction time were obtained (Fig.1.a).

0 20 40 60 80 100 120 1400

102030405060708090

100

Con

cent

ratio

n [%

]

Time [min]

primary amine nitrile Schiff base secondary amine oxime

C N OH

R C NR

HR

HCH NH

2RHC N CH2

R

HCH NH2

R

Figure 1. a)Time-concentration diagram for 2-ethylbutyraldoxime hydrogenation (Raney-Ni, reaction temp.=140°C, pH2=40 bar, solvent THF), b) reaction sequence. The aldoximes are not directly transformed into amines (Fig. 1.b). The primary products identified during the reaction were nitrile and Schiff base. Reference reactions showed that amine can be formed via Schiff base, nitrile or simultaneously from both intermediates. The significance of the two parallel reaction pathways was derived by macrokinetic modelling of the reaction sequence. Both reaction pathways had about the same significance. However the nitrile reduction provides a higher selectivity to primary amine. We also checked that primary amine can be transformed during reaction into secondary amines. However, this reaction is of minor importance.

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Selective palladium catalyzed one-pot synthesis of N-heterocycles: homogeneous vs heterogeneous catalytic system

Marie Genelota, Anissa Bendjerioub, Véronique Dufaudb and Laurent Djakovitcha* a Université de Lyon, CNRS, UMR 5256, IRCELYON, Institut de recherches sur la catalyse et l’environnement

de Lyon, 2 avenue Albert Einstein, F-69626 Villeurbanne, France b Laboratoire de Chimie, UMR 5182 CNRS-ENS Lyon, 46 Allée d’Italie, F-69364 Lyon cedex 07, France

Carbonylated heterocycles like flavones, aurones or their nitrogen analogues like quinolones or indoxyls are an important class of bioactive molecules. Several stoichiometric strategies exist for their preparation, however for economical and environmental reasons we developed a one-pot palladium catalyzed synthesis of such compounds. The formation of N-heterocycles was achieved through a carbonylative Sonogashira coupling/cyclization sequence. Reaction parameters were optimized in homogeneous phase aiming at a better understanding of the reaction mechanism that will be fully discussed in this presentation. Thus 4-quinolone or indoxyl derivatives were selectively obtained.

However the palladium contamination of the final products and the non-recyclability of the catalyst are generally the drawbacks of homogenous catalysis. For that reason, we then undertook the development of heterogeneous catalytic systems. Different Pd-complexes grafted on mesoporous silica SBA-15 were prepared and evaluated. The results obtained so far will be presented and compared to those achieved in homogeneous reactions in order to demonstrate the benefits of using heterogeneous catalysis.

I

NH2

+ CO + R

O

NH2

R

NH

NH

O

R

O

R

[Pd], NEt3

anisole, 80°C, 5bar

R'R'

R'

R'

4-quinolone

indoxyl

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The isomerization of n-butanol of the Li3 Cr2(PO4)3 catalyst

Vasile Georgescu

Institute of Physical Chemistry “Ilie Murgulescu”, Romanian Academy, Spl. Independentei 202, Bucharest, Romania, (e-mail: [email protected])

Alcohol-based fuels have been important energy sources. Alcohols have been used as fuels in three main ways: as a fuel for a combustion engine, as a fuel additive to achieve octane boosting effects similar to the petroleum-based additives and metallic additives like tetraethyllead and as a fuel for direct conversion of chemical energy into electrical energy in a fuel cell.

Butanol is a chemical that has excellent fuel characteristics. It contains approximately 22% oxygen, which when used as a fuel extender will results in more complete fuel combustion. Use of butanol as a fuel will contribute to clean air by reducing smog-creating compounds, harmful emissions (CO) and unburned hydrocarbons in the tail pipe exhaust.

Butanol has research and motor octane numbers of 113 and 94, compared to 111-92 for ethanol. The value of octane boosting is dependent of isomers content of butanol.

Li3Cr2(PO4)3 catalyst was prepared and studied.

Li3Cr2(PO4)3 catalyst possessed high catalytic activity and stability in the dehydration and isomerization of butanol.

The catalyst was prepared by solid state synthesis. The highest activity in the transformations of butanol was observed after treating the catalyst with plasma [1].

The plasma chemical technology for obtaining catalysts is based on the character of plasma action on solids[2-4].

Catalytic experiments were performed at 100-5000C in a flow unit. The products were analyzed chromatographically.

The activity of Li3Cr2(PO4)3 in butanol transformations was studied for four surface states: initial sample and after plasma chemical treatment in oxygen, hydrogen and argon.

The modification of the surface of catalysts and their regeneration under the action of a plasma causes the appearance of a new surface structures, which increase activity, selectivity and operation stability. References 1.A.I.Pylina, I.I.Mikhalenko, A.K.Ivanov-Shits, T.V.Yagodovskaya and V.V.Lunin, Russian J. Phys. Chem. 80 (6) 882 (2006) 2.T. V. Yagodovskaya and V. V. Lunin, Zh. Fiz. Khim. 71(5), 775 (1997) [Russ. J. Phys. Chem. 71 (5), 681(1997)]. 3. V. V. Lunin, E. A. Dadasheva, T. V. Yagodovskaya, andO. M. Knipovich, Abstracts of Papers, 2nd All-UnionMeeting “Application of Plasma in the Technology ofCatalysts” (Kiev, 1991), p. 18. 4. A. L. Lapidus, I. G. Solomonik, A. Yu. Krylova, andE. G. Krashenninikov, Abstracts of Papers, IV RussianConference with the Participation of CIS Countries“Scientific Fundamentals of the Preparation and Technologyof Catalysts” (Ufa, 2000), p. 35.

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The role of H•••F interactions in fluorinated post-metallocenes catalysts at ab-initio level

Vincenzo Villani, Gaetano Giammarino and Michael C. W. Chan*

Dipartimento di Chimica, Università degli Studi della Basilicata, Via N. Sauro 85, 85100 Potenza, Italy [email protected]

*Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Av., Kowloon, Hong Kong

Recently, Fujita et al. (1) proposed via DFT calculations in post-metallocene catalysts, a reactivity role of C-H···F-C weak hydrogen-bond between the fluorinated ligand and the growing chain. Chan et al. (2-3) extended via X-Ray diffraction and NMR spectroscopy the presence of H···F

interactions to arylpyridine tridentate complexes to explain the higher activity of fluorinated Group IV catalysts. Currently, we are investigating via GAUSSIAN03 energy optimizations on parallel architecture the possible interactions between the perfluoromethyl group of the ligand and the benzylic methylene of Chan catalysts. The potential energy curve of the rotating trifluoromethyl group has been calculated and two interaction schemes are been considered: a 3-centers H···F···H interaction, and a double 2-centers H···F interaction. The conformer with 3-

centers interaction seems to be more stable, thus giving an insight about the preferred interaction between olefins and ancillary fluorinated groups.

X-ray crystal structure of a 2-(2’-hydroxyphenyl)-6-arylpyridine catalyst1

Due to the weak bonding between carbon-bonded hydrogen and fluorine lone pairs, we are now studying the best combination of parameters to further investigate the strength of interaction. ______________ References: 1 M. Mitani, J. Mohri, Y. Yoshida, J. Saito, S. Ishii, K. Tsuru, S. Matsui, R. Furuyama, T. Nakano, H. Tanaka, S. Kojoh, T. Matsugi, N. Kashiwa and T. Fujita J. Am. Chem. Soc. 2002, 124, 3327-3336 2. M. C. W. Chan, S. C. F. Kui, J. M. Cole, G. J. McIntyre, S. Matsui, N. Zhu and K. Tam, Chem. Eur. J. 2006, 12, 2607 – 2619 3. S. C. F. Kui, N. Zhu and M. C. W. Chan Angew. Chem. Int. Ed. 2003, 42, 1628 – 1632

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Catalyzed transfer hydrogenation of ketones: a microflow process

Marta Giménez-Pedrós, Piet. W. N. M. van Leeuwen

Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona, Spain

Nowadays, nearly all chemical transformations involve catalytic processes. Catalysis plays a key role in all conversions by making them faster, more selective and highly reproducible [1]. Homogeneous catalysis has grown dramatically over the last years. In most laboratories homogeneous catalysis research is conducted on a relatively large scale, often on a millilitre or much larger scale. Over the past decade, interest in miniaturisation of chemical reactions has grown rapidly. Microflow reactors have received significant interest in the stream of downsizing of chemistry and they are expected to make an innovative change for chemical synthesis. Microflow systems for the study of homogeneous catalysis are relatively rare, but the interest is rapidly growing. Both experimental studies and calculations show there are several catalytic conversions that could benefit from conductance in microflow reactor systems [2] by raising conversion and selectivity. In addition it may be advantageous for other reasons such as a rapid screening of conditions, handling of dangerous materials, high pressures or highly exothermic reactions [3].

The reduction of ketones using catalytic hydrogen transfer, with 2-propanol as hydrogen source, has been widely investigated in the last years [4]. One of the most active systems described in the literature is based on a ruthenium complex associated with a terdentate ligand (Figure 1), affording TOF values up to 2.5 x 106 h-1 [5].

O

+OH [Ru]/base

OH

+

O

N

NH2

RuCl

PPh2

PPh2

1

[Ru] =

Scheme 1

Herein we present the application of the ruthenium complex (1) in the catalyzed transfer hydrogenation of ketones using microreactors. The effect of the concentration of the reactants, and flow rate has been studied.

Figure 1. Microchannel: internal diameter 0.3 mm, l = 1-1.5 m. A, B, C liquid inlets

[1]van Leeuwen, P. W. N. M. “Homogeneous Catalysis: Understanding the Art”, Kluwer (now Springer), Dordrecht, 2004 [2]www.mikroglas.com [3] Ehrfeld , W., Hessel, V., Löwe, H. “Microreactors: New Technology for Modern Chemistry”, Wiley-VCH, Weinheim 2000 [4]Gladiali, S.; Alberico, E. Chem. Soc. Rev. (2006), 35, 226 [5] Baratta ,W.; Chelucci, G.; Gladiali, S.; Siega, K.; Toniutti, M.; Zanette, M., Zangrado, E.; Rigo, P. Angew. Chem. Int. Ed. (2005), 44, 6214

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http://www.mikroglas.com/

Improving the enantioselectivity of asymmetric Suzuki coupling reactions using chiral Pd nanoparticles

Cyril Godard, Angelica Balanta Castillo, Serafino Gladiali, and Carmen Claver

Departament de Química Física I Inorgànica, Universitat Rovira I Virgili, C/ Marcel.li Domingo s/n 43007 Tarragona, Spain

Recently, the use of metal nanoparticles (NPs) as catalysts for organic substrate transformations has generated great interest.[1] The properties of these nanocatalysts is mainly controlled by the size of the nanoparticles and the nature of the stabilising agents, often sulphur donor ligands. Phosphorus donor ligands, however, has received much less attention to stabilise NPs.[2]

The Suzuki-Miyaura cross-coupling reaction is one of the most versatile reaction and successful synthetic tools for C-C bond formation in organic chemistry.[3] Despite the great interest of the achiral reaction for the production of biaryl derivatives, very little attention has been paid to the asymmetric variant of this process.[4] Recently, room temperature reaction with good yield and enantioselectivity was achieved using diphosphine stabilised Pd NPs as catalysts.[5] The use of nanoparticles supported on resin was also shown to be very effective in this reaction.[6]

Here we present the successful use of Pd-nanoparticles stabilised by chiral monophosphine ligands in the asymmetric Suzuki coupling of binaphthyls with ee’s up to 93%.

Scheme 1. Asymmetric Suzuki coupling of binaphthyls.

[1] See for instance: a) D. Astruc, Nanoparticles and Catalysis, Wiley-VCH, Weinheim, 2008; b) A. Roucoux, J. Schulz, H. Patin, Chem. Rev. 2002, 102, 3757; c) J. A. Widegren, R. G. Finke, J. Mol. Catal. A 2003, 198, 317; d) M. M. Manas, R. Pleixats, Acc. Chem. Res. 2003, 36, 638. [2] a) M. Tamura, H. Fujihara, J. Am. Chem. Soc. 2003, 125, 15742; b) Y. Yanagimoto, Y. Negishi, H. Fujihara, T. Tsukuda, J. Phys. Chem. B 2006, 110, 11611; c) S. U. Son, Y. Jang, K. Y. Yoon, E. Kang, T. Hyeon, Nano Lett. 2004, 4, 1147. [3] For recent reviews, see: G. Bringmann, A. J. P. Mortimer, P. A. Keller; M. J. Gresser, J. Garner, M. Breuning, Angew. Chem. Int. Ed. 2005, 44, 5384. [4] a) A. N. Cammidge, K. V. L. Crepy, Chem. Commun. 2000, 1723; b) J. Yin, S. L. Buchwald, J. Am. Chem. Soc. 2000, 122, 12051; c) A.-S. Castanet, F. Colobert, P.-E. Broutin, M. Obringer, Tetrahedron: Asymmetry 2002, 13, 659; d) J. F. Jensen, M. Johannsen, Org. Lett. 2003, 5, 3025; e) A. Herrbach, A. Marinetti, O. Baudoin, D. Guenard, F. Gueritte, J. Org. Chem. 2003, 68, 4897; f) A. N. Cammidge, K. V. L. Crepy, Tetrahedron 2004, 60, 4377; g) K. Mikami, T. Miyamoto, M. Hatano, Chem. Commun. 2004, 2082; h) P. Kasak, K. Mereiter, M. Widhalm, Tetrahedron: Asymmetry 2005, 16, 3416; i) O. Baudoin, Eur. J. Org. Chem. 2005, 4223; j) M. Ciclosi, J. Lloret, F. Estevan, P. Lahuerta, M. Sanau, J.-P. Prieto, Angew. Chem. 2006, 118, 6893; Angew. Chem. Int. Ed. 2006, 45, 6741; k) M. Genov, A. Almorin, P. Espinet, Chem. Eur. J. 2006, 12, 9346; l) T. Takemoto, S. Iwasa, H. Hamada, K. Shibatomi, M. Kameyama, Y. Motoyama, H. Nishiyama, Tetrahedron Lett. 2007, 48, 3397; m) M. Genov, A. Almorin, P. Espinet, Tetrahedron: Asymmetry 2007, 18, 625. [5] K. Sawai, R. Tatumi, T. Nakahodo, H. Fujihara, Angew. Chem. Int. Ed. 2008, 47, 6917. [6] Y. Uozumi, Y. Matsuura, T. Arakawa, Y. M. A. Yamada, Angew. Chem. 2009, 121, 1.

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Synthesis, Characterization and Catalytic Evaluation of La0.75Sr0.25Co0.5Fe0.5O3 oxide in the Catalytic Decomposition of

Hydrogen Peroxide

Gómez-Cuaspud, Jairo A1*; Valencia-Ríos, Jesús S1 and Carda Castelló, Juan B2. 1Laboratorio de Catálisis Heterogénea, Departamento de Química, Facultad de Ciencias, Universidad Nacional

de Colombia, Bogotá, D.C, Colombia. * [email protected] 2 Grupo de Química del Estado Sólido, Departamento de Química Inorgánica y Orgánica, Universitat Jaume I de

Castelló, Castelló de la Plana, España.

This paper describes the synthesis and characterization of a polycationic oxide based on La0.75Sr0.25Co0.5Fe0.5O3 system (LSCoF), using a wet chemical route involving the formation of intermediate species, that evolved of citrate type precursors until the final solid consolidation depending on temperature, with the aim of obtaining non-densified materials for potential applications as electrodic components in solid oxide fuel cells (SOFCs). The prediction of the main chemical species in aqueous solution was determined using Medusa's software[1], which allowed us to determine the chemical nature of precursor disolution in wide ranges of pH, to avoid the potential formation of insoluble species. The obtained solid was characterized by X-ray diffraction (XRD) and modeled with the SPuDS[2] Software, allowing to determine the formation of a perovskite type phase with a index tolerance factor (Bond Valence Parameter) of 0.9801, orthorhombic space group Pbnm (62), a = 5.396 Å, b = 5.458 Å, c = 7.719 Å, consistent with JCPDS: 089-1267; the scanning electron microscopy (SEM) and determination of specific surface area by BET method, allowing evaluate the texture and relief characteristic of solid due to the synthesis method, giving a strong degree of porosity and roughness showing areas exceeding 10 m2.g-1. The size of crystallites, calculated with the Scherrer Calculator software, confirmed the presence of nanometric solids (≈ 20 nm), while the overall composition determined by microprobe energy dispersive X-ray (EDX), indicated a good correlation between the proposed and obtained composition. The catalytic test was carried out using the catalytic decomposition of hydrogen peroxide in alkaline medium, establishing that the reaction is of pseudo first order with respect to peroxide, assuming that the mass of catalyst and concentration of the base not affect the reaction rate; the isotherms activity, the apparent activation energy (63.4 kJ mol-1) and the activity observed in general it´s relate to a promising material as a catalyst in partial or total oxidation reactions.

a. b. c. d. Figure 1. a. X.R.D. pattern of LSCoF sample, which indicates the presence of perovskite type crystalline phase; b. Estimated interatomic distances for each component and unit cell of LSCoF system; c. SEM micrographs at 50 μm. d. Isotherms of activity in the decomposition of hydrogen peroxide at different temperatures. References [1] Puigdomenech, Ignasi. Make equilibrium Diagrams Using Sophisticated Algorithms MEDUSA. Vers. 29 Apr. 2002. Royal Institute of Technology. Stocholm, Sweden. [2] M.W. Lufaso, P.M. Woodward, (2001) "The Prediction of the Crystal Structures of Perovskites Using the Software Program SPuDS" Acta Cryst., B57, 725-738.

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Quantification of active sites in immobilized Single Site Catalyst‡

Itzel Guerrero Rios, Elena Novarino, Bart Hessen and Marco Bouwkamp

Molecular Inorganic Chemistry, Stratingh Institute for Chemistry, University of Groningen / Dutch Polymer Institute (DPI), PO Box 902 5600 AX Eindhoven

Industrial application of single-site catalysts for the production of polyolefines requires their successful immobilization on solid support to yield heterogeneous catalyst systems.[1] A drawback of these systems is the lack of immobilization methods that allow a study of the nature, stability and behavior of the active species on the support. This contribution aims at a well-defined and quantifiable method for the generation of catalytically active species on silica supports using an immobilized anilinium borate activator.[2]

Reaction of the borate-modified silica with Cp2*ZrMe2 generates the active species [Cp*

2ZrMe]+, that in the presence of a functionalized α-olefine (allyl methyl thioether) form a stable 5-ring chelate, as a result of a single insertion into the zirconium-methyl bond.[3] To release the chelate from the support an ion exchange reaction with tetrabutyl ammonium bromide provides desorption of the trapped species from the support and allows quantification and characterization in solution by NMR spectroscopic techniques. The number of active species will be correlated with the performance of the system in ethylene polymerization.

‡ This work is part of the Research Program of the Dutch Polymer

Institute (DPI), Eindhoven, The Netherlands, project nr. #639. [1] a) Hlatky, G. Chem. Rev. 100 (2000) 1347. b) Severn, J.R., Chadwick, J.C., Duchateau, R. and

Frederichs, N. Chem. Rev. 105 (2005) 4073. [2] Jacobsen, W.B., Wijkens, P., Jastrebski, J.T.B.H. and van Koten, G. US Patent 5.834.393 (1998). [3] Bijpost, E.A., Zuideveld, M.A., Meetsma, A., Teuben, J.H. J. Organomet. Chem. 551 (1998) 159. E-mail: [email protected] www: http://bouwkamp.fmns.rug.nl/

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mailto:i.guerrero.rios@rug.

Lanthanide Metal-Organic Frameworks as Effective and Size-Selective Lewis Acid Catalysts

Mikaela Gustafssona,b, Agnieszka Bartoszewicza,c, Belén Martín-Matutea,c, Junliang Suna,b, Jekabs Grinsa,b, Tony Zhaob, Xiaodong Zoua,b

a Berzelii Centre EXSELENT on Porous Materials, b Structural Chemistry, c Organic Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden

Within the great research field of porous and functional materials, metal-organic frameworks, MOFs, belong to a new member of the porous solid family. MOFs are three-dimensional crystalline coordination polymers built by metal ions or clusters that are linked together by organic ligands, called linkers.1 Since the choice of metals and linkers is unlimited, there is a wide range of possibilities to construct different MOFs. Micro- and even meso-pores can be generated in the MOF structures. Heterogeneous catalysis is one of the application areas where MOFs can play an important role. The interest of introducing catalytic properties into MOFs is increasing during the recent years.2 Metal ions or linkers can act as catalytic centers. Immobilization of homogeneous complexes into MOFs is also possible.

A family of isotypical lanthanide-based MOFs, Ln(BTC)(H2O)⋅DMF (Ln: Nd (1),3 Sm (2), Eu (3), Gd (4), Tb (5), Ho (6), Er (7) and Yb (8)), possessing high thermal stability was synthesized. The 3D structure contains 1D quadratic channels of size 7.0 x 7.0 Å2 with accessible lanthanide ions. Since lanthanide ions can adopt flexible coordination spheres, they are suitable for creating coordinatively unsaturated metal centers. Therefore, the potential to use our LnMOFs as heterogeneous Lewis acid catalysts for cyanosilylation of aryl aldehydes and aryl ketones was investigated (Figure 1). The study of size-selectivity, heterogeneity and recycling of the LnMOFs by different catalytic tests will be presented.

Figure 1. Cyanosilylation of acetophenone catalyzed by a metal-organic framework, Nd(BTC)(H2O)⋅DMF. References: 1. a) Yaghi, O. M.; O´Keeffe, M.; Ockwig, N. W.; Chae, H. K.; Eddaoudi, M.; Kim, J. Nature 2003, 423, 705-

713. (b) Férey, G. Chem. Soc. Rev. 2008, 37, 191-214. 2. (a) Forster, P. M.; Cheetham, A. K. Topics in Catalysis, 2003, 24, 79-86. (b) Kesanli, B.; Lin, W.

Coordination Chemistry Reviews, 2003, 246, 305-326. (c) Kitagawa, S.; Kitaura, R.; Noro, S.-I. Angew. Chem. Int. Ed., 2004, 43, 2334-2375. (d) Schüth, F. Annu. Rev. Mater. Res., 2005, 35, 209-238. (e) Ngo, H. L.; Lin, W. Topics in Catalysis, 2005, 34, 85-92. (f) Wang, Z.; Chen, G.; Ding, K. Chem. Rev., 2009, 109, 322-359.

3. Gustafsson, M.; Li, Z.; Zhu, G.; Qiu, S.; Grins, J.; Zou, X. Studies in Surface Science and Catalysis, eds. Gedeon, A; Massiani, P; Babonneau, Proceedings of the 4th International FEZA Conference, 2008, 174 (B), 451-454.

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Switchable Solvents – Combination of Reaction and Separation

D. J. Hahne1, C. A. Eckert2, C. L. Liotta2, W. Leitner1*

1Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Germany.2 School of

Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, USA

Solvents which can reversibly switch from molecular to ionic forms upon applying an external stimulus were recently reported by the Jessop-Liotta-Eckert groups.[1,2,3] Specifically, an equimolar mixture of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or 2-n-butyl-1,1,3,3-tetramethylguanidine (TMBG) and an alcohol like methanol or hexanol can be switched from the molecular form to a room temperature ionic liquid by simple exposure to atmospheric pressure of CO2. The ionic liquids can as easily be switched back to the molecular form by purging with Ar or N2 and/or heating. The switch from molecular to ionic form results in a step-change in properties like polarity, density and viscosity.

N N

N

+ ROH

CO2 (1 bar), RT

Ar or N2or heat (60 °C)

N N

NH

RO O

O

N

NN

NH

TMBG

alcohol

DBU

RTIL Figure 1: Reaction of an equimolar mixture of DBU or TMBG and an alcohol with CO2 to form the corresponding ionic liquids. The unique properties of the switchable ionic liquids are opening new avenues to efficiently perform reaction and separation especially for catalytic reactions. This is exemplified for Pd-catalyzed C-C-coupling reactions, where along with the desired organic product stoichiometric amount of salts are formed as by-products, which both need to be separated for catalyst recycling. Using reversible IL, the product can be extracted out of the ionic liquid after successful reaction. Then after switching the solvent back to the molecular species the salts precipitate and can be readily removed by filtration.

Thus, the switchable solvents allow to reversibly adjust the solubility properties of the medium exactly to the separation problem, providing new strategies for efficient catalyst recycling.

[1] P. G. Jessop, D. J. Heldebrant, X. Li, C. A. Eckert, C. L. Liotta, Nature 2005, 436, 1102. [2] L. Phan, D. Chiu, D. J. Heldebrant, H. Huttenhower, E. John, X. Li, P. Pollet, R. Wang, C. A. Eckert, C. L. Liotta, P. G. Jessop, Ind. Eng. Chem. Res. 2008, 47(3), 539-545. [3] V. Blasucci, C. Dilek, H. Huttenhower, E. John, V. Llopis-Mestre, P. Pollet, C. A. Eckert, C. L. Liotta, Chem. Commun., 2009, 116-118.

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Hydroaminomethylation of n-Alkenes in a Biphasic Ionic Liquid System[1]

Bart Hamers, Patrick S. Bäuerlein, Christian Müller, Dieter Vogt

Schuit Institute of Catalysis, Laboratory of Homogeneous Catalysis, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands, E-mail: [email protected]

Both in bulk and fine chemical industry, amines are of great importance, for example as active pharmaceutical ingredients or building blocks for polymers. Easy and selective access to these intermediates, atom efficiency, availability and price of starting materials, and waste reduction have been important issues over the past decades. In this perspective, a promising reaction is the hydroaminomethylation, which could fulfill the abovementioned requirements and was discovered by Reppe in 1949 at BASF.[2] This hydroaminomethylation is a transition metal catalyzed cascade reaction, combining in one pot an alkene hydroformylation and a reductive amination of the intermediate aldehyde with an amine (secondary, primary or ammonia), leading to the desired amine product (Scheme 1).

R1

R1 O

HCO/H2

R1 NR2R3 R1 NR2R3H2HNR2R3

linear aminealdehyde enamine

[cat.] [cat.]-H2O

Scheme 1: Formation of linear amine in the hydroaminomethylation reaction

One of the important issues in homogeneous catalysis is the robustness and recyclability of the catalyst system in addition to high activity and selectivity.[1,4] With this goal in mind, a rhodium/Sulfoxantphos system was applied in ionic liquids (Scheme 2). Apart from the excellent activity and chemo- and regioselectivity for the linear amine (l/b ratios up to 78), the resulting biphasic system allowed easy product separation and catalyst recycling. In order to investigate the consumption and formation of (side)products and intermediates in these reactions, product distributions were examined during the reaction at different temperatures, both in an organic solvent and in the ionic liquid. Additionally, it was shown that the type of Rh precatalyst and the use of protic organic solvents or ionic liquids containing a C-H acidic bond in the imidazolium part have a profound effect on activity and selectivity of the catalyst system. The aforementioned effects will be compared and discussed.

ionic liquid

organic layer

N

BF4

NN

HN

O

PPh2PPh2

SO3NaNaO3S

CO/H2

Rh(cod)2BF4/Sulfoxantphos

Scheme 2: Catalytic hydroaminomethylation system in an ionic liquid

[1] B. Hamers, P.S. Bäuerlein, C. Müller, D. Vogt, Adv. Synth. Catal. 2008, 350, 332-342. [2] W. Reppe, H. Vetter, Liebigs Ann. Chem. 1953, 582, 133-163. [3] B. Zimmermann, J. Herwig, M. Beller, Angew. Chem. Int. Ed. 1999, 38, 2372-2375. [4] B. Hamers, E. Kosciusko-Morizet, C. Müller, D. Vogt, ChemCatChem 2009, submitted.

ACTS-ASPECT is kindly acknowledged for financial support.

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New Chiral Alkyl Rare Earth Catalysts for Asymmetric Intramolecular Hydroamination

Jérôme Hannedouche, Isabelle Aillaud, Jacqueline Collin, Emmanuelle Schultz and Alexander Trifonov*

Laboratoire de Catalyse Moléculaire, ICMMO, UMR CNRS 8182, Université Paris Sud 11, Bat 420, 91405 Orsay Cedex, France. e-mail: [email protected].

*G. A. Razuvaev Institute of Organometallic Chemistry of Russian Academy of Sciences, Tropinia 49, 603600 Nizhny Novgorod GSP-445, Russia

Asymmetric catalytic intramolecular hydroamination of alkenes has recently emerged as potentially a powerful atom-economic tool for the stereoselective generation of C-N. Despite time and efforts dedicated to the development of efficient chiral catalysts over the last decade, only a few catalytic systems promote this transformation with enantioselectivity >90% and in barely few cases.1 Herein, we report a convenient route to rapidly access efficient rare-earth catalysts for room temperature-asymmetric intramolecular hydroamination reaction that does not involve prior metathetical synthesis of homoleptic lanthanide precursors in an independent step.2 This approach that relies on the combination of LnCl3, a chiral diamine ligand (R)-L and R’Li (n-BuLi or MeLi) in a 1:1:4 ratio is found to rapidly provide efficient chiral catalysts for asymmetric hydroamination of gem-disubstituted aminoalkenes. A modified procedure involving in situ generation of chiral catalysts in the d6-benzene reaction media is also described.

LnCl3 (6 mol%) + (R)-L (6 mol%)+ R'Li (18 mol%)

C6D6, r.t.

concentration in vacuo

THF, r.t., 10 min

NH2R

R

HN

R

R

NHNH

(R)-L

up to 99% conv. up to 79% e.e.

n = 1,2

n n

______________ References: 1. Reviews: (a) Aillaud I., Collin J., Hannedouche J., Schulz E., Dalton Trans., 2007, 5105; (b) Hultzsch K. C.,

Adv. Synth. Catal., 2005, 347, 367. 2. (a) Hannedouche, J.; Aillaud, I.; Collin, J.; Schulz, E.; Trifonov, A. Chem. Commun. 2008, 3552; (b) Aillaud

I.; Lyubov D.; Collin, J.; Guillot, R.; Hannedouche, J. ; Schulz, E. ; Trifonov, A. Organometallics 2008, 27, 5929.

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Nickel Complexes of Bulky, Electron-Rich Phosphinomethyl Functionalized N-Heterocyclic Carbene Ligands for Catalysis

Haufe. R., Blumbach U., Rominger F., Prof. Dr. Hofmann P.*

Organisch-Chemisches Institut, Universität INF 270, D-69120, Germany

[email protected]

A new class of N-phosphinomethyl substituted N-heterocyclic carbene ligands (NHCP) with alkyl substituents both at phosphorus and at the imidazol-2-ylidene moiety has been synthesized. Their strong donor character and variable steric bulk at the imidazol-2-ylidene moiety causes remarkable effects upon the structures and properties of their transition metal complexes. Only a few examples of comparable ligand systems forming 5-membered chelate rings are known in the literature.[1]

Square planar, neutral dibenzyl and dimethyl NHCP-complexes of nickel have been synthesized. Treatment of the dibenzyl complex with 1 equiv. of [Et3O]BF4 yields a distorted η3-monobenzyl cation, which was structurally characterized and compared to its bisphosphine (tBu2PCH2PtBu2, dtbpm) analog, which functions as highly active, co-catalyst-free ethylene polymerization catalyst[2] due to a facile switch from η3- to η1-coordination. Protonation of the dimethyl complex resulted in the monomethyl cation. Furthermore other NHCP nickel complexes, as precursors for cationic complexes, were synthesized.

N N

Bu2P

tBu

Nit Bn

Bn

Et3OBF4

N N

Bu2P

tBu

Nit

BF4-

r.t.

As a potential application of such cationic nickel complexes, the polymerisation of olefins is under investigation in our lab. Literature: [1] A. A. Danopoulos, N. Tsoureas, S. A. Macgregor, C. Smith, Organometallics 2007, 26, 253-263. [2] M. O. Kristen, P. Hofmann, F. Eisenträger (BASF AG), WO 0202573 A1, 2002

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Hydroformylation of 1-octene over Co-based Catalysts

Lan Ma1,2, Dehua He1*

1 Key Lab of Organoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084, P.R. China;

2 Institute of Chemical Defence, Beijing 102205, P.R. China * E-mail: [email protected]

The hydroformylation of olefins is a very important homogeneous industrial process[1]. However, it is still not easy to separate homogeneous catalysts from products and to recycle them in the homogeneous processes. Immobilization of homogeneous catalysts is an interesting and challenging research, and a great of efforts have been made to improve the catalyst-product separation in homogeneous processes. Some solid Co or Rh metal catalysts supported on inorganic supports have also been investigated for the hydroformylation[2]. Recently, we employed metal-metalloid amorphous Co-B materials as catalysts in the hydroformylation of 1-octene, and investigated the behaviors of the Co-B catalysts in the hydroformylation and examined their recycle use in octene hydroformylation.

Pure amorphous Co-B catalyst and supported Co-B catalysts were prepared by chemical reduction method[3]. The prepared catalysts were characterized by isothermal N2 adsorption/desorption, XRD, XPS, ICP-AES and TEM. The hydroformylation of 1-octene was carried out in a stainless steel autoclave of 100 ml. The products were analyzed qualitatively by GC-Mass and analyzed quantitatively with a gas chromatography.

The pure amorphous Co-B catalyst showed relatively high activity and the selectivity in the hydroformylation of 1-octene in a laboratory-scale batch reactor under the conditions of Co/Olefin molar ratio=0.096, 120oC, 8MPa. The thermal-treatment temperatures of pure Co-B and the reaction temperatures had great influence on the activity. When Co-B was supported on some supports, the specific activity of the catalysts increased obviously. Compared with conventional supported Co/SiO2 catalyst, supported amorphous Co-B/SiO2 showed much higher activity. The pure Co-B catalyst exhibited relatively high stability (both in activity and selectivity) in the recycles in 1-octene hydroformylation (120oC, 5Mpa). However, the activity of supported Co-B catalysts decreased with the increase of the recycle times, owing to the loss of Co from the catalysts during the reactions.

Reference [1] F. Ungvary, Coord. Chem. Rev., 167(1997) 233. [2] Y. Zhang, K. Nagasaka, X. Qiu, N. Tsubaki, Catalysis Today 104 (2005) 48. [3] C. Wu, F. Wu, Y. Bai, et al., Materials Letters, 59(2005)1748.

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Ru-Re Bicomponent Catalysts for Hydrogenolysis of Glycerol to Glycols

Lan Ma1,2, Dehua He1* 1 Key Lab of Organoelectronics & Molecular Engineering of Ministry of Education, Department of Chemistry,

Tsinghua University, Beijing 100084, P.R. China; 2 Institute of Chemical Defence, Beijing 102205, P.R. China

* E-mail: [email protected]

Glycerol is a by-product of bio-diesel production. With the increase of bio-diesel production, the development of down-stream products of glycerol has recently attracted much attention[1]. By catalytic hydrogenolysis, glycerol can be converted to glycols (propylene glycol and ethylene glycol), which are important and high added-value chemicals[2], and Ru can be used as catalyst in glycerol hydrogenolysis[3]. However, the activity and selectivity for glycerol hydrogenolysis with Ru catalysts alone are still low. Recently, we investigated the hydrogenolysis of glycerol to propylene glycol and ethylene glycol over highly active Ru-Re bicomponent catalysts. In present paper, we report some interesting results.

Supported Ru-Re bicomponent catalysts and Ru monocomponent catalysts (using SiO2, Al2O3, ZrO2, TiO2, etc as supports) were prepared by impregnation method. The catalysts were characterized by N2 adsorption/desorption, XRD, TEM-EDX, H2-TPR and CO chemisorption. The glycerol hydrogenolysis (160oC and 8.0 MPa H2 pressure) was carried out in a 100 ml stainless steel autoclave with a magnetic stirrer. The products in liquid phase were analyzed qualitatively by GC-Mass and analyzed quantitatively with a gas chromatography.

The results of characterization indicate that the addition of Re component could improve the dispersion of Ru species on supports, and the coexistence of Re and Ru components on supports changed the respective reduction behavior of Re or Ru alone on the supports. Compared with Ru monocomponent catalysts, the Ru-Re bicomponent catalysts showed much higher activity in the hydrogenolysis of glycerol, and Re exhibited obvious promoting effect on the performance of the catalysts. There existed a synergistic effect between Ru and Re species on the bicomponent catalysts. It was also found that the preparation parameters could obviously affect the catalytic performance of Ru-Re bicomponent catalysts and corresponding Ru monocomponent catalysts.

Reference [1] A. Behr, J. Eilting, K. Irawadi, J. Leschinski and F. Lindner, Green Chem., 10 (2008) 13. [2] J. Chaminand, L. Djakovitch, P. Gallezot, et al, Green Chem., 6(2004) 359. [3] T. Miyazawa, S. Koso, K. Kunimori, et al., Appl. Catal. A., 318(2007) 244.

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An Ag/TiO2 Catalyst for Simultaneous Removal of Hydrogen Cyanide and Formic Acid Traces from Synthesis Gas

Konrad Herbst*, Anna Puig Molina, Jens Bæk Simonsen, Pablo Beato and Matteo Caravati

Haldor Topsøe A/S, Nymøllevej 55, DK-2800 Lyngby, Denmark

The industrial production of synthesis gas from hydrocarbon feedstocks by the Autothermal Steam Reforming process (ATR process, equations I and II) is carried out at temperatures of up to 1100 ºC. Since the hydrocarbon feedstock or the oxidant often contain some N2, the production of synthesis gas at these temperatures may be affected by the formation of traces of ammonia (III) and hydrogen cyanide (IV). Formic acid/formamide is also prone to be formed in ppm amounts (V).

(I) Steam reforming: -CH2- + H2O ↔ CO + 2H2 (II) Autothermal reforming/partial combustion: -CH2- + 0.5O2 → CO + H2 (III) Ammonia formation: N2 + 3H2 ↔ 2 NH3 (IV) Hydrogen cyanide formation: NH3 + CO ↔ HCONH2 ↔ HCN + H2O (V) Formic acid formation: HCN + 2H2O ↔ HCONH2 + H2O ↔ HCOOH + NH3

These trace components may lead to problems in condensate treatment units or in poisoning and deactivation of catalysts in downstream synthesis gas based processes, e.g. the production of methanol or the Fischer-Tropsch synthesis of hydrocarbons. While NH3 may be easily removed from the raw synthesis gas by a washing/scrubbing process step, HCN and HCOOX (X = H, NH2) must be removed by catalytic decomposition. Haldor Topsøe A/S has addressed this problem by developing a new process for the simultaneous catalytic removal of trace amounts of HCN and HCOOX from wet synthesis gas [1].

The catalyst for this process, Ag/TiO2, shows excellent activity and stability in the removal of HCN and HCOOH at 185°C/28bar (Figure 1) without altering the synthesis gas composition by water gas shift or methanation reactions. Characterization of the catalyst in the working state by in-situ EXAFS and in-situ Raman techniques show the conversion of an oxidic silver phase (presumably Ag2CO3) to metallic Ag particles with an average size of approx. 18 Å. This corresponds well with the size distribution of the Ag particles obtained by Scanning Transmission Electron Micro-scopy (STEM).

Catalytic Decomposition of HCN / HCOOH 185 °C / 28 bar / SV = 30,000 Nl/kg/h

0

20

40

60

80

100

0 200 400 600 800 1000

time on stream, hours

HC

N /

HC

OO

H c

onve

rsio

n, %

HCOOHHCN

Figure 1

References [1] K. Pedersen, I. Dybkjær, P.E. Højlund Nielsen, J. Nerlov, WO2007/124865 (Haldor Topsøe A/S).

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Catalytic Properties of Ni3Al Foils for Methane Steam Reforming

Yan Ma†*, Ya Xu§, Masahiko Demura§ and Toshiyuki Hirano†§

†University of Tsukua, Sengen, Tsukuba, Ibaraki 305-0047, Japan *Presently North China Electric Power University, Beijing 102206, P. R. China

*§National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan

Ni3Al intermetallic compound has never been regarded as a catalyst so far. Rather it has been well known as an excellent high-temperature structural material. Recently we have successfully fabricated its thin foils by metallurgical process, cold-rolling1, and then found high catalytic activity for methanol decomposition in the foils. Methanol was effectively decomposed into hydrogen and carbon monoxide over the foils2,3. It is quite unusual that flat metallic foils exhibit high activity because of their low surface area.

It is intriguing to examine whether the foils exhibit catalytic activity for another hydrogen production reaction, methane steam reforming. In this study we investigated the catalytic properties using the cold-rolled foils with Ni-24 at%Al composition. Before reaction tests, the foils were oxidized in steam condition at 873 K for 1 h and then reduced at 873 K for 1 h in flowing hydrogen. This pretreatment was intended to form catalytically active fine Ni particles on the foil surface. The catalytic properties were examined under S/C=1 condition in a conventional fixed-bed flow reactor.

Figure 1 shows the methane conversion over the pretreated and as-rolled foils as a function of reaction temperature. Though the as-rolled foils exhibit some catalytic activity, obviously the pre-treatment effectively improves the catalytic activity, i.e., it decreases the onset temperature and increases the activity. We will present the detailed catalytic properties and the results of characterization of the foil surface.

Fig. 1 Methane conversion over the pre-treated and as-rolled foils.

1 M. Demura, K. Kishida, Y. Suga, M. Takanashi, T. Hirano, Scripta Mater. 47((2002)267. 2 D.H. Chun, Y. Xu, M. Demura, K. Kishida, M.H. Oh, T. Hirano, D.M. Wee, Cat. Lett. 106（2006）71. 3 D.H. Chun, Y. Xu, M. Demura, K. Kishida, D.M. Wee T. Hirano, J. Catalysis, 243(2006)99.

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Incorporation of Phosphanylated Amino Acids into RNase A

Joscha Holldorf, Evamarie Hey-Hawkins*

Universität Leipzig, Institute of Inorganic Chemistry, Johannisallee 29, 04103 Leipzig, Germany

Phosphanylated amino acids have proven to be interesting ligands in catalysis and offer a wide range of applications.[1] Peptides, proteins and enzymes containing phosphanylated amino acids are used in stereoselective transition metal catalysis. These new catalysts allow the properties of homogeneous and enzymatic catalysis to be combined. Furthermore, the electronic and steric properties of the phosphane can be modified by changing the substituents.

The aim of our research is to synthesise a variety of phosphanylated amino acids, which then are incorporated into peptides via solid-phase peptide synthesis. These peptides must feature an α-helical structure, so that two amino acids in positions i and i+4 are able to coordinate to a catalytically active late transition metal (e.g., rhodium, palladium, platinum). These synthesised peptides can be incorporated into the variable part of the binding pocket of the enzyme RNase A. This enzyme can then act as ligand for late transition metals, and the catalytic behaviour of the late transition metal complexes can be investigated.

Fig. 1: Preparation of phosphanylated amino acids via substitution.

Phosphanylated amino acids are synthesised from chlorophosphanes by the Knochel cuprate method[2] and from secondary thiophosphane oxides via a new and easy substitution route (Fig. 1). Not only alkylated and arylated phosphanes are synthesised, but also phosphanes with a second donor atom, which are able to chelate transition metals (Fig. 2).

Fig. 2: Preparation of chealting phosphanylated amino acids.

[1] A. Agarkov, S. Greenfield, D. Xie, R. Pawlick, G. Starkey, S.R. Gilbertson, Biopolymers, 2005, 84, 48. [2] P. Knochel, M.C.P. Yeh, S.C. Berg, J. Talbert, J. Org. Chem., 1988, 53, 2392.

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Homogeneous vs Supported Chiral ONN-Pincer Gold and Palladium Complexes: Catalytic Activity

Carolina del Pozo, Nathalie Debono, Avelino Corma, Marta Iglesias* and Félix Sánchez*

Instituto de Ciencia de Materiales de Madrid, CSIC. C/ Sor Juana Inés de la Cruz 3, Cantoblanco 28049 Madrid, Spain. Instituto de Química Orgánica, CSIC. C/ Juan de la Cierva 3, 28006 Madrid, Spain.

The ONN-tridentate unsymmetrical pincer (S)-1-((6-(2-hydroxyphenyl)pyridin-2-yl)methyl)-N-methyl-N-(3-(triethoxysilyl)propyl)pyrrolidine-2-carboxamide, ligand was synthesised by an easy method in high purity and good yields. The respective Palladium (II) and gold (III) complexes have been prepared as air stable solids, with the ONN-tridentate ligand after deprotonation of the –OH group, the coordination of the metal ion is completely stereospecific and gives rise to only one diastereoisomer1. These complexes have been immobilized on ordered mesoporous silica (MCM-41)2 (scheme) and were shown to be very active catalysts in the hydrogenation of prochiral olefins (98 % ee was achieved with the heterogenized chiral Au(MCM-41 complex) (table 1), hydrosilylation and C-C coupling, Suzuki and Heck, reactions, under mild conditions.

N

OH OTsN BrBr

NNOH

NH

O

N

ON

SiOO

O

O

N

N

O

N SiO

O

OM

L

Support

Toluene Su p

port

O

N

N

O

N Si

OH

OOM

L

M: Pd, L: OAc, M: Au; L: Cl

[Pd], [Au][Pd](MCM-41), [Au](MCM-41)

SiO

O

O

The reactivity was studied with the soluble as well as with the heterogenized counterpart catalysts. The high accessibility introduced by the structure of the supports allows the preparation of highly efficient

immobilized catalysts. The repeated use of the immobilized catalyst in four recycles (the catalyst is truly immobilized with the post catalysis solution showing no activity) demonstrates ‘homogeneous’ catalysis with ‘heterogeneous’ catalysts, thus reducing solvent waste, and loss of precious metal and or ligand. In order to check the stability of metal complexes supported on the solid matrix, we have characterized the solid before and after reaction. As can be deduced from IR, 13C NMR and UV-Vis spectra the nature of supported species is very similar and the most important signals for ligands appear in the same position after reaction.

Table 1. Catalytic results from soluble and inmobilized MCM-41-Pd/Au complexes in asymmetric hydrogenation reactions[a]

[Pd] [Pd](MCM-41) [Au] [Au](MCM-41)

TOF[b] 565 78 580 166 Ee (%)[c] 15 30 80 98 [a]Conditions: 4 atm, 40 ºC, catalyst: 0.1 mol%. [b]TOF: mmol substrate/mmol catalyst min. [c]Determined by HPLC

1 N. Debono, M. Iglesias, and F. Sánchez, Adv. Synth. Catal. 2007, 349, 2470 – 2476 2 C. González-Arellano, A. Corma, M. Iglesias, F. Sánchez, Adv. Synth. Catal. 2004, 346, 1758-1764

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Asymmetric α-arylation of carbonyl compounds with chiral diaryliodonium salts

Nazli Jalalian and Berit Olofsson*

[email protected]; [email protected] Department of Organic Chemistry, Stockholm University, Arrhenius laboratory, SE-106 91 Stockholm, Sweden,

Phone: 0046-(0)8-162467, Fax: 0046-(0)8-154908

α-Arylated ketones are abundant substructures in natural products and pharmaceutically active compounds, and can easily be derivatized to the corresponding alcohols or amines. Although α-alkylations of enolates have been thoroughly investigated, direct arylation reactions of enolates have been reported only recently, employing Pd catalysis with excess base and prolonged heating.1,2 Chiral, unsymmetric diaryliodonium salts have been synthesized from an enantiopure, electronrich arene. The use of these salts in asymmetric α-arylations of ketones leads to selective transfer of the phenyl group, with the electron rich moiety group behaving as chiral ligand. As the formed aryl iodide can easily be recovered and reoxidized to iodine(III), this approach combines the benefits of chiral auxiliaries (covalent attachment of the chiral group often gives high asymmetric induction) and chiral reagents/ catalysts (no extra steps required for attachment/ cleavage).

1 Hartwig, J. F. and coworkers, J. Am. Chem. Soc. 2008, 130, 195 2 Garca-Fortanet, J.; Buchwald, S. L., Angew. Chem. Int. Ed. 2008, 47, 8108

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Catalytic properties of Ni3Al foil catalysts modified by oxidation-reduction for methanol decomposition

Jun Hyuk Jang, Ya Xu*, Masahiko Demura*, Dang Moon Wee, Toshiyuki Hirano*

Department of Materials Science and Engineering, KAIST, Daejeon 305-701, Korea *National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, Japan

Ni3Al foil catalysts were found to show high catalytic activity for methanol decomposition due to the formation of fine Ni particles on the foil surface by selective oxidation/hydroxylation of Al in Ni3Al [1,2]. The result suggests that pre-treatment of the foils which form large amount of fine Ni particles on the surface is promising for enhancing the catalytic activity. Recently, the authors have found that it is possible to achieve such surface modification by two-step treatment, oxidation in air followed by reduction in hydrogen [3]. In this study, we examined the catalytic properties of the pre-treated Ni3Al foil catalysts.

Surface structure of cold-rolled Ni3Al foils were modified by oxidation at 973 and 1173 K for 1 and 5 h, and subsequently followed by reduction in hydrogen at 773 K for 1 h. Methanol decomposition was carried out over the modified Ni3Al foil catalysts at the temperature range from 513 to 793 K.

Figure 1 shows methanol conversion over the modified and as-rolled Ni3Al foil catalysts as a function of reaction temperature. The modified Ni3Al foil catalysts exhibited high catalytic activity for methanol decomposition into H2 and CO, compared to the unmodified foil catalysts in the whole reaction temperature region. Isothermal test revealed that the modified Ni3Al foil catalysts exhibited high catalytic activity at 673 K during 24 h of reaction test. These results indicate that the surface modification with oxidation-reduction treatment effectively improved the catalytic activity of Ni3Al foil catalysts.

Fig. 1 Methanol conversion over the modified and as-rolled Ni3Al foils

200 250 300 350 400 450 500 550

0

10

20

30

40

50

60

70

80 700oC, 1 h 900oC, 1 h 900oC, 5 h As-rolled

Met

hano

l Con

vers

ion

[%]

Reaction temperature [oC]

References [1] D.H. Chun, Y. Xu, M. Demura, K. Kishida, D.M. Wee, T. Hirano, J. Catal. 243 (2006) 99-107. [2] J.H. Jang, Y. Xu, D.H. Chun, M. Demura, D.M. Wee, T. Hirano, in press, J. Mol. Catal. A: Chemical (2009),

in press. [3] J.H. Jang, Y. Xu, M. Demura, D.M. Wee, T. Hirano, Mater. Res. Soc. Symp. Proc. Vol. 1129, 1128-U05-36.

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Catalyst immobilization on soluble supports via ‘click’ chemistry

Michèle Janssen, Christian Müller, Dieter Vogt*

Schuit Institute of Catalysis, Laboratory of Homogeneous Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

A major drawback of homogeneous catalysts over heterogeneous systems is the difficulty to recycle the catalyst. One way to overcome this problem is the immobilization of homogeneous ligands on suitable supports.

We have selected a number of well-known phosphine ligands and connected them to different soluble macromolecular supports (dendrimers, polymers and dendronized polymers) via ‘click’ chemistry. It turned out that the aromatic 1,2,3-triazole ring that is formed in this [3+2]-cycloaddition reaction is sufficiently stable to withstand reaction conditions typically applied in homogeneous catalysis. Two examples of a supported triphenylphosphine are depicted in Figure 1.

Figure 1: polymer supported (left) and dendrimer supported (center) triphenylphosphine and nanofiltration setup (right). We report here on the synthesis of supported ligands and the application of the corresponding Pd-complexes in the palladium catalyzed Suzuki-Miyaura coupling of aryl halides and boronic acids. The supported systems show very similar activities as their conventional homogeneous analogues and can be recycled efficiently by means of nanofiltration. [1] Detz, R.J., Arévalo Heras, S., de Gelder, R., van Leeuwen, P.W.N.M., Hiemstra, H., Reek, J.N.H. van

Maarseveen, J.H., Org. Lett., 2006, 3227-3230. [2] Gaikwad, A.V., Boffa, V., ten Elshof, J.E., Rothenberg, G., Angew. Chem. Int. Ed. 2008, 5407-5410. [3] Janssen, M., Müller, C., Vogt, D., Adv. Synth. Catal. 2009, 313-318

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Palladium-catalyzed Isomerization and Hydroformylation of Olefins

Reiko Jennerjahn[a], Irene Piras[a], Ralf Jackstell[a], Robert Franke[b], and Matthias Beller*[a]

[a] Leibniz-Institut für Katalyse e.V. an der Universität Rostock, Albert-Einstein-Straße 29a, 18059 Rostock (Germany), Fax: (+49) 381-1281-5000

[b] OXENO Olefinchemie GmbH, Marl, Germany

The palladium-catalyzed hydroformylation of 1-octene has been studied in the presence of different phosphines and acid co-catalysts. Best results are achieved in the presence of in situ-generated palladium complexes with bidentate phosphines. A novel optimized catalyst has been applied for hydroformylation of different aliphatic and aromatic olefins. Good activity and excellent selectivity towards the linear aldehydes is achieved. For example the hydroformylation of styrene tooks place with a linear/branched ratio of 85:15, other metals prefer the branched product because of coordination to the ring.

By stirring the catalyst system in the presence of 1-octene at room temperature without any hydrogen pressure also fast isomerization reactions took place:

0%

20%

40%

60%

80%

100%

0 50 100 150 200

time [min]

1-octene 4-octene 3-octene trans-2-octene cis-2-octene

2days

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On the mechanism of CO2 insertions into palladium pincer allyl complexes

Magnus T. Johnson, Ola F. Wendt*

Organic Chemistry, Department of Chemistry, Lund University, P.O. Box 124, S-221 00 Lund, Sweden [email protected], [email protected]

The catalytic carboxylation of organic substrates with carbon dioxide as the C1 source is a highly attractive reaction. By means of environmental aspects, the high abundance and the non-toxicity makes CO2 synthetically interesting.

Specifically, insertion of CO2 into a palladium pincer σ-allyl bond has been reported to take place very fast in room temperature.1 The reaction mechanism has not been elucidated in detail although proposals has been made with a bis-allyl palladium(II) complex2,3 and in the catalytic carboxylation of allenes with a PSiPPd catalyst.4 The mechanism could take place by either a normal β-insertion or through a six-membered cyclic transition state resembling the metallo-ene reaction. (Fig. 1)

P(tBu)2(tBu)2P Pd

CO

O

P(tBu)2(tBu)2P Pd

O O

P(tBu)2(tBu)2P Pd

O

O

Figure 1. The metallo-ene mechanism.

In order to differentiate between the two mechanisms, several different substituted σ-allylic pincer complexes were used since the product substition pattern clearly reveals the mechanistic pathway. (Fig. 2)

P(tBu)2(tBu)2P Pd

CO2

CO2

P(tBu)2(tBu)2P Pd

O O

P(tBu)2(tBu)2P Pd

O O

Metallo-ene mechanism

1,2-insertion

Figure 2. Carboxylation of a crotyl derivative.

Multi-nuclear NMR experiments clearly indicates that the reaction follows the metallo-ene type of mechanism. Theoretical calculations of the mechanistic pathways are currently proceeding.

References: 1. R. Johansson, O. F. Wendt, Dalton Trans., 2007, 488–492 2. M. Shi, K. M. Nicholas, J. Am. Chem. Soc. 1997, 119, 5057-5058 3. R. J. Franks, K. M. Nicholas, Organometallics 2000, 19, 1458-1460 4. J. Takaya and N. Iwasawa, J. Am. Chem. Soc., 2008, 130, 15254–15255

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Efficient Reoxidation of Palladium by a Hybrid Catalyst in Aerobic Palladium-Catalyzed Carbocyclization of Enallenes

Eric V. Johnston, Erik A. Karlsson, Staffan A. Lindberg, Björn Åkermark, and Jan-E. Bäckvall*

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden

Abstract. A new efficient reoxidation system for palladium was used in the palladium-catalyzed aerobic carbocyclizations, which allows a low catalytic loading. Palladium is efficiently reoxidized by hybrid catalyst 1 consisting of a cobalt Schiff-base catalyst with a covalently bound quinone.

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Magnetic Nanoparticle Supported Metal Alkoxides for Ring-Opening Polymerization of Lactones

Wei Long and Christopher W. Jones

School of Chemical & Biomolecular Engineering, School of Chemistry and Biochemistry, Georgia Institute of Technology, 311 Ferst Dr., Atlanta, GA 30332, USA

Polymerization catalysts are routinely single use catalysts, as neither the homogeneous (no easy recovery mechanism), nor the heterogeneous catalysts (polymer clogs catalyst pores and entraps the active sites) are easily recoverable and recyclable. Biodegradable poly(esters) that have wide applications in the biomedical and related industries can be produced by ring-opening polymerization (ROP) of cyclic lactone monomers. Although many highly active homogeneous metal complex catalysts have been reported as catalysts for the ROP of lactones, their application can be hampered by the difficulty and cost associated with recovering the metal residue. Heterogeneous catalysts (based on porous materials) for lactone polymerization can be easily recovered, however they usually cannot be reused due to pore clogging with polymer. We have identified magnetic nanoparticles (MNPs) as an ideal alternative support for recoverable polymerization catalysts due to their nonporosity, high external surface area, potential for facile surface modification, and easy recoverability under a magnetic field.

Here, MNP-supported metal alkoxides based on aluminium and yttrium are reported as a recoverable and recyclable catalysts for the ROP of ε-caprolactone. The preparation, characterization and catalytic performce of these new catalysts are reported. Recoverability and recyclability are also demonstrated.

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Microwave-assisted, palladium-catalyzed synthesis of arylphosphinates

Marcin Kalek, Martina Jezowska, and Jacek Stawinski*

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm,

Compounds containing mono- and diarylphosphinate structural motifs have attracted attention due to their increasing practical and scientific applications.1 Recently, we have found that application of microwave irradiation greatly accelerates a palladium-catalyzed cross-coupling of H-phosphonate diesters with aryl halides.2 Inspired by this observation, we set out to explore if microwave heating could also be used to facilitate coupling of anilinium phosphinate, the method of choice for the synthesis of arylphosphinates.3 This substrate seems to be even better suited for the microwave conditions than H-phosphonate diesters, since as ionic species it was expected to absorb very efficiently microwave energy via a conduction mechanism.

In series of experiments, the reaction conditions have been optimized with respect to supporting palladium ligand, solvent, heating mode and temperature. It was found that the microwave-promoted reaction is most efficient with wide-bite-angle Xantphos ligand. Experiments indicated that the reaction acceleration originated from the high temperature but participation of specific microwaves effects cannot be excluded.

Using the optimized conditions a number of mono- and diarylphosphinates have been synthesised. In many cases catalyst loading as low as 0.1 mol% could be applied to achieve a complete conversion into the products after only 10 minutes reaction time. Also, for the first time, unsymmetrical diarylphosphinic acids could be efficiently synthesized in an one-pot reaction.

References 1. G. Lligadas, J. C. Ronda, M. Galia, V. Cadiz, J. Polym. Sci., Part A: Polym. Chem. 2006, 44, 5630-5644; M.

Schuman, X. Lopez, M. Karplus, V. Gouverneur, Tetrahedron 2001, 57, 10299-10307. 2. M. Kalek, A. Ziadi, J. Stawinski, Org. Lett. 2008, 10, 4637-4640. 3. J. L. Montchamp and Y. R. Dumond, J. Am. Chem. Soc. 2001, 123, 510-511.

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Oxidation of ethers, alcohols and unfunctionalized hydrocarbons by the MTO/H2O2 system: a computational study of the catalytic

C-H bond activation

Erik A. Karlsson and Timofei Privalov*

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden

The potential energy surfaces (PESs) of methyltrioxorhenium (MTO) catalyzed C-H insertion reactions in the presence of hydrogen peroxide are studied by accurate DFT methods for a series of substrates including unsaturated hydrocarbons, an ether and an alcohol. Based on the comprehensive analysis of transition states and an intrinsic reaction coordinate (IRC) scans, the C-H insertion is found to proceed via a concerted mechanism that does not require, as previously thought, a side-on or a butterfly-like transition state. We have found that a typical transition state follows requirements of the SN2 reaction instead. Furthermore, based on the exploration of the PESs of several C-H insertion reactions we discovered that no ionic intermediate is formed even in a polar solvent. The latter was modeled within the selfconsistent reaction field approach in a polarizable continuum model (PB-SCRF/PCM).

According to our study, the C-H insertion occurs via concerted but highly asynchronous mechanisms that at first proceeds via a hydride transfer and than turns into a hydroxide transfer/rebound. For the oxidation of alcohols, the C-H bond cleavage occurs without the formation of the alkoxide intermediates within the dominant pathway. The computed deuterium kinetic isotope effect for the hydride transfer-transition state for alcohol oxidation, 2.9, is in good agreement with the experimental kH/kD ration of 3.2 reported by Zauche and Espenson. As confirmed by IRC- and PES-scans in different solvents, the OH-rebound phase of the C-H insertion pathway demonstrates strong similarities with the rebound mechanism, which was previously proposed for cytochrome P450 and metalloporphyrin-catalyzed oxidations.

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A new generation of grafted organometallic complexes: the use of hydroxyborate anions as anchors for zirconium based catalysts

Vinciane Kelsen,a Christophe Vallée,a Christine Bibal,b Catherine C. Santini,b Yves Chauvinb and Hélène Olivier-Bourbigoua

a IFP-Lyon, Rond point de l'échangeur de Solaize, 69360, Solaize, France b Université de Lyon, ICL, LC2P2, LCOMS, UMR 5265 CNRS-ESCPE Lyon, 43, bd du 11 Novembre 1918,

69626, Villeurbanne Cedex, France

In order to combine both advantages of homogeneous and heterogeneous catalysis we propose a new way of grafting organometallic complexes. Our strategy is to immobilize catalytically active metal complexes on bulky weakly-coordinating anions [HOB(C6F5)3]- by the formation of a M-O-B core.1

Molecular speciesMolecular species -- eeaassyy cchhaarraacctteerriizzaattiioonn

-- ggoooodd ccoonnttrrooll aanndd ddeessiiggnn ooff tthhee mmeettaall ccoooorrddiinnaattiioonn sspphheerree

Immobilization on bulky anionsImmobilization on bulky anions CCaattaallyysstt ssttaabbiilliizzaattiioonn aanndd rreeccyyccllee

F

F

B O

MLnXm

F

weakly coordinating anionic part

metal oxygen covalent bond

metallic center

ligands

aprotic cation

N PP

Ph

Ph

Ph

Ph

Ph

Ph

This grafting methodology was demonstrated by the reaction of Cp2ZrMe2 with [PPN]+[HOB(C6F5)3]-. The protonolysis of a Zr-Me bond led to the formation of the supported complex which was fully characterized by standard spectroscopic method and X-ray diffraction.

This route for the incorporation of a covalently bonded anionic functionality has been applied to other alkyl zirconium precursors. The use of the supported complexes as olefins polymerization and/or oligomerization catalysts will be presented. 1. Bibal C., Santini C.C., Chauvin Y., Vallée C. and Olivier-Bourbigou H. Dalton Trans. 2008, (21), 2866.

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Synthesis of β-hydroxy 1,2,3-triazoles in the presence of copper nanoparticles on charcoal via Huisgen cycloaddition reaction in

water

Reza Khalifeha*, Hashem Sharghib* aDepartment of chemistry, Shiraz university of technology, Shiraz 75555-313, I. R. Iran

bDepartment of Chemistry, Shiraz University, Shiraz, 71454, Iran

1,2,3-Triazoles are an important class of heterocyclic compounds due to their wide range of applications including as pharmaceutical agents.1 Huisgen 1,3-dipolar cycloaddition of an azide and an alkyne is an efficacious way for synthesis multifarious the 1,2,3-triazole ring system.2

In this reaction, the copper (I) catalytic species are directly formed from Cu(I) salts in the presence of ligands,3a or prepared in situ by reduction of Cu(II) salts with ascorbate,3b oxidation of copper(0) metal3c or by comproportionation of Cu(0) and Cu(II).3d To improve the recovery and reuse, copper species have been immobilized onto various supports such as activated carbon, amine-functionalized polymers, zeolites, amine-functionalized silica and aluminum oxyhydoxide fiber. Recently some examples were reported for in situ generation of organic azides using a one-pot procedure to prepare 1,2,3-triazole derivatives based on the three component coupling reaction.

As part of our continued efforts to utilize heterogeneous catalysts for developing organic reaction, and as a continued interest to develop efficient synthesis of 1,2,3-triazoles via [3 +2] cycloadditions, herein we report a highly efficient three-component coupling of epoxides, alkynes, and sodium azide (A3 Coupling) catalyzed by Cu/C in water. The reaction is general and can be applied to both aromatic and aliphatic alkynes.

The heterogeneous catalysts were fully characterized by scanning electron microscopy (SEM), atomic forced microscopy (AFM), X-ray diffraction (XRD), inductively coupled plasma (ICP) analysis and FT-IR experimental techniques. The catalyst was recycled ten times without significant loss of activity.

Reference: 1. W.-Q. Fan, R. AKatritzky, in Comprehensive heterocyclic chemistry II Eds: A. R. Katritzky, C. W. Rees, E. F. V. Scriven, Elsevier Science: Oxford, 1996; Vol. 4, pp 1-126. 2. R. Huisgen in 1,3-Dipolar Cycloaddition Chemistry, Ed.: A. Padwa, Wiley, New York, 1984, Vol. 1, p. 1 – 176. 3. a) A. Marra, A. Vecchi, C. Chiappe, B. Melai, A. Dondoni, J. Org. Chem. 2008, 73, 2458. b) V. V. Rostovtsev, L. G. Green, V. V. Fokin, K. B. Sharpless, Angew. Chem., Int. Ed. 2002, 41, 2596. c) F. Himo, T. Lovell, R. Hilgraf, V. V. Rostovtsev, L. Noodleman, K. B. Sharpless, V. V. Fokin, J. Am. Chem. Soc. 2005, 127, 210. d) S. Quader, S. E. Boyd, I. D. Jenkins, T. A. Houston, J. Org. Chem. 2007, 72, 1962.

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Supportless Recycling of Ligand and Osmium in Asymmetric Dihydroxylation through Water Soluble Catalytic System

Daewon Lee, Seyoung Kim and B. Moon Kim*

Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 151-747, South Korea E-mail: [email protected]

Osmium catalyzed asymmetric dihydroxylation (AD) of olefins is one of the most efficient reactions for the synthesis of enantiomerically pure vicinal diols.1 However, the high cost of osmium/chiral ligand and low turnover, as well as the high toxicity of osmium obstruct the large-scale industrial application of the AD reaction. To address this problem, we prepared new water-soluble interface ligands and they were applied to supportless recycling of metal-ligand system in AD reactions for a highly efficient and environmentally friendly recycling protocol.

Asymmetric dihydroxylation of olefins using water soluble ligand employing recently developed chemoentrapment method2 in aqueous medium proceeded in high yields exhibiting excellent asymmetric inductions comparable with those obtained with homogeneous ligand. In repetition test, QNPNa(1) and TetraNa(2) showed almost the same levels of enantioselectivities as those of initial runs. In this system, the solvent water acts as recycling matrix, combining the advantages of both homogeneous reaction conditions and heterogeneous catalysis. This new catalyst recycling system is expected to pave a way to practical and environmentally friendly methods toward industrial applications of AD.

References 1. For reviews, see: Kolb, H. C.; Van Nieuwenhze, M. S.; Sharpless, K. B. Chem Rev. 1994, 94, 2483. 2. Lee, D. W.; Lee, H. G.; Kim, S. Y.; Yeom, C. E.; Kim, B. M. Adv. Synth. Catal. 2006, 348, 1021.

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Recycling of Osmium Catalyst Using Chemoentrapment Strategy: Oxidative Olefin Cleavage

Seyong Kim, Jooyoung Chung and B. Moon Kim*

Department of Chemistry, College of Natural Sciences, Seoul National University, Seoul, 151-747, South Korea E-mail: [email protected]

Oxidative cleavage of olefins is one of quite useful tools in the arsenal of organic reactions. Lemieux-Johnson reaction and its variants are widely used for the oxidative cleavage of 1,2-diols and olefins. Although very useful, these reactions often require quite expensive metal catalysts such as osmium or ruthenium. Typically OsO4/NaIO4 reaction for the cleavage of olefins often does not constitute an economically viable reaction on a large scale. In this regard, ways to minimize the use of expensive metal catalysts are of a great interest to organic chemists. We have developed a new chemoentrapment strategy for recycling osmium in the catalytic dihydroxylation1 and have extended this mehtod to olefin cleavage reaction. The new strategy allowed for an efficient recycling of osmium in the reactions involving mono- and di-substituted olefins with 1.0 mol% of OsO4 without any significant side reactions and loss of yield.

After obtaining aldehyde products from the cleavage reaction, the osmium catalyst remains as Os(VIII) from oxidation using a secodary oxidant such as sodium periodate. To trap the osmium sepcies, 2-propanol and KOH was added into the system and the Os(VIII) is reduced to Os(VI). After treatment, osmium exists as OsO4

2- in an aqueous layer. Products can then be extracted using organic solvents and osmium in water layer can be recycled for further reactions. Various solvents were screened to optimize this oxidative cleavage and new secondary oxidant systems were searched to provide NaClO2 as an optimal oxidant.

References 1. Lee, D. W.; Lee, H. G.; Kim, S. Y.; Yeom, C. E.; Kim, B. M. Adv. Synth. Catal. 2006, 348, 1021.

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Role of Water in Asymmetric Heterogeneous Catalysis Using Pd/C

TaeYeon Kim, Takashi Sugimura*

Graduate School of Material Science, University of Hyogo, Kamigori, Ako-gun, 678-1297 Japan *E-mail: [email protected]

Enantioselective hydrogenation of α,β-unsaturated acids can be performed with the heterogeneous asymmetric catalyst prepared by the modification of a certain supported Pd catalyst with cinchonidine (CD) [1]. Water is indispensable as an additive to the hydrogenation solvent, and 2.5% wet dioxane or DMF is usually preferred. However, a small amount of water in the catalyst (not in the solvent) was found to play a critical role. When Pd/C was used as obtained, Pd/C after the CD-modification afforded the low product ee. Although the heat pretreatment (80°C) of Pd/C under the hydrogenation conditions is known to improve the ee [2], it was newly found that evaporation to remove the water also gave the high ee. The water should be captured at a specific carbon interior in Pd/C and cannot easily be exchanged with the solvent. Water contaminant in Pd/C must be common phenomena, but becomes obvious only when two different molecules, the non-polar chiral modifier and the polar substrate, should access the same catalyst site to perform the enantioselective reaction.

Addition of water to the solvent is still necessary, but too much addition resulted in decrease of the enantioselectivity. A typical example is seen in the hydrogenation of phenylcinnamic acid ethanolamine salt. The high ee up to 82% becomes as low as 32% when the reaction was carried out in water. Use of water for the hydrogenation with Pd/C has a big advantage in the practical use; the catalyst can easily ignite by contact with organic solvent even if it is less flammable methanol, and use of water as a reaction media could eliminate this potent problem. However, water has high dielectronic constant, and molecular recognition due to the intramolecular polar interaction should become weak. Here, we assumed if the carbon support of the catalyst adsorbs organic compound in water as regular active carbon does, the circumstance around Pd metal should become hydrophobic by the effects of the adsorbed organic compounds. Based on this idea, a small amount of toluene. The additive effect was dramatic and the ee becomes the same as or even higher than that in organic solvent [3]. The hydrogenation in water with CD-modified Pd/C with toluene could be applied for different substrates irrespective of the hydrophilicity or hydrophobicity of the substrate. The high ee with this hydrogenation system could be achieved by both the affinity between toluene and carbon and the strong surface tension to keep the carbon hydrophobic. The additional advantage of this method is that separation of the product was easy and the repeated use of the catalyst became possible, because the product is mostly dissolved in water while the almost all Pd/C and CD stay in toluene droplets that float on the water surface.

Water is a ubiquitous substance and its use as a reaction media is called green process. The present results indicate that role of water in heterogeneous asymmetric catalysis can be more than that.

References [1] T. Sugimura, in K. Ding, Y. Uozumi (editors), Handbook of Asymmetric Heterogeneous Catalysis, Wiley-VCH, Verlag, 2008, p. 357. [2] Y. Nitta, J. Watanabe, T. Okuyama, T. Sugimura, J. Catal. 236 (2005) 164. [3] T. Sugimura, T. Y. Kim, Catal. Lett., in press.

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Mechanistic investigations of the hydrogenation of imines

Leif R. Knöpke, Navid Nemati, Angela Köckritz, Ursula Bentrup, Angelika Brückner

Leibniz Institut für Katalyse an der Universität Rostock e.V. Albert-Einstein-Str. 29a; D-18059 Rostock; Germany

In recent years the homogeneously catalysed enantioselective hydrogenation of imines by chiral Brønsted acids has been developed but the exact mechanism is still under discussion[1]. We pursue a new approach to identify selective catalysts for the asymmetric hydrogenation of C=N bonds comprising the use of supported noble metal catalysts for the activation of hydrogen in combination with a suitable chiral acid for introducing enantioselectivity. The degree of interaction of the imine with the chiral acid seems to be an essential step. We have studied this interaction in different solvents to elucidate its strength and the influence of the solvent properties on the reaction using solutions with an imine concentration of 0.5 mol/L. The chiral acid was added in 20 mol% steps until the stochiometric ratio of 1:1 between acid and imine was archieved.

The interaction between imine and chiral acid was followed simultaneously by ATR-FTIR and Raman spectroscopy using fiber optical probes. Both spectroscopic methods showed comparable results so that the ATR spectra are exemplarily discussed.

The position of the imine’s typical ν(C=N) band varies depending on the used solvents (Fig. 1). The position of this band ranges from 1638 cm-1 in dichloromethane to 1629 cm-1 in 1,1,1-trifluoroethanol (TFE). In methanol a splitted ν(C=N) band (1638/1629 cm-1) is observed. The appearance of the additional band at 1629 cm-1 can be explained by the formation of hydrogen bonds between the lone electron-pair of the nitrogen atom and the OH group of the solvent, comparable to the intramolecular hydrogen bonds of salicylideneaniline[2]. During continuous addition of chiral acid no change of the ν(C=N) at 1638 cm-1 band is observed in dichloromethane, this band is totally missed in methanol. In TFE, a broadening of the ν(C=N) band after chiral acid addition is seen. This points to specific interactions between imine, the chiral acid, and the solvent. The disappearance of the ν(C=N) band in methanol may indicate a possible protonation of the imine. Apparently, the interaction of the proton with the acid anion and the imine and consequently the strength of the backbond between acid anion and acid proton[3] could be the key factor for the weakening of the C=N-double bond. As strong hydrogen bond donor and weak hydrogen bond acceptor[4], TFE has completely different behaviour to methanol. [1] S. Hoffmann, A. M. Seayad, B. List, Angew. Chem. Int. Ed. 44 (2005) 7424. [2] O. Berkesi, T. Körtvélyesi, C. Hetényi, T. Németh, I. Pálinkó, Phys Chem. Chem. Phys. 5 (2003) 2009. [3] C. Sandorfy, D. Vocelle, Can. J. Chem. 64 (1986) 2251. [4] I. A. Shuklov, N. V. Dubrovina, A. Börner, Synthesis 19 (2007) 2925.

1638

Figure 1: ATR-FTIR spectra of imine's protonation

1638 1629

1638

CH2Cl2

MeOH

TFE

1700 1650 16001750 Wavenumbers / cm-1

Tran

smitt

ance

pure imine solution (c=0.5 mol/L)

1550

solution of imine and chiral acid (ratio 1:1; c=0.5 mol/L)

1629

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Applications of Palladium on Charcoal in cross-coupling reactions Komáromi, A., Daru, J. and Novák, Z*.

H-1117 Budapest, Pázmány Péter stny 1/A. Eötvös Loránd University, Institute for Chemistry, Department of Organic Chemistry, Hungary

[email protected] , [email protected]

Palladium-catalyzed cross-coupling reactions are one of the most frequently used synthetic tools for the construction of new carbon-carbon or carbon-heteroatom bonds in organic synthesis. With the application of homogeneous palladium catalysts several coupling reactions can be achieved even with less reactive aryl chlorides.

Ar X

R3Sior

Ar

R3Si

Hiyama coupling

R1

Pd/CLigand

Pd/C

NH2R2

or

R2 NH

Pd/CLigand

Sonogashira couplingBuchwald-Hartwig coupling

Application of solid supported palladium catalysts makes the process more beneficial and provides an opportunity for the recycling of the relatively expensive catalyst and ligand. Although, the most readily available solid supported catalyst is the palladium on charcoal, its application in Buchwald-Hartwig amination and Hiyama coupling is unprecedented. Herein, we report a straightforward and economic procedure for the palladium on charcoal catalyzed cross-coupling of aryl-halides with terminal acetylenes1, amines and silanes. 1 A. Komáromi, Z. Novák, Chem. Commun., 2008, 4968-4970.

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Highly regioselective hydroxycarbonylation of styrene using Pd complexes of novel bidentate diphosphines

Tina M. Konrad, Jamie J. R. Frew, Alexandra M. Z. Slawin, Matthew L. Clarke*

School of Chemistry,EaSTCHEM, University of St Andrews, St Andrews, Fife, UK, KY16 9ST *[email protected]

Pd-catalysed hydroxycarbonylation of aryl alkenes is potentially the most efficient route to aryl propanoic acids, and has consequently attracted much industrial interest.1 Catalysis using Pd-catalysts of phosphine ligands furnish the desired (racemic) branched acids with good regioselectivity and productivity. Presently there are no truly efficient chiral catalysts for regio- and enantioselective hydroxycarbonylation of alkenes, perhaps in part due to the regioselectivity and activity problems that bidentate phosphine-based catalsts have.

The current dogma is that Pd-monophosphine catalysts give the desired branched acids with good activity, whereas Pd-diphosphine catalysts tend to give mixtures of linear and branched acids in poor yield.2 No truly effective asymmetric catalysts have been discovered thus far for the active Pd-monophosphine systems.

Extensive work has demonstrated a dramatic effect on reactivity and selectivity by modifying reaction conditions and catalyst structure.2,3 We have investigated very bulky diphosphines, with an ultimative aim of realising the first efficient asymmetric process. The use of palladium complexes of these novel ligands showed them to be highly regioselective and active catalysts for the hydroxycarbonylation of styrene (Figure 1).4

Figure 1. Optimised hydroxycarbonylation with Encouraged by these results, we are currently investigating Pd-complexes of enantiopure bulky diphophines to develop higly regio- and enantioselective processes. The present results are outlined in this poster. This project will also move on to develop supported catalysts for Pd-carbonylation processes. ____________ References: 1. (a) I. del Rio, C. Claver and P. W. N. M. van Leeuwen, Eur. J. Inorg. Chem. 2001, 2719; (b) A. Zapf and M.

Beller, Top. Catal. 2002, 19, 101. 2. I. del Rio, N. Ruiz, C. Claver, L. A. van der Veen, P. W. N. M. van Leeuwen, J. Mol. Catal. A 2000, 161, 39. 3. (a) I. Del Rio, N. Ruiz, C. Carmen, Inorg. Chem. Commun. 2000, 166 ;(b) H. Ooka, T. Inoue, S. Itsuno, M.

Tanaka, Chem. Commun. 2005, 1173; (c) A. Ionescu, G. Laurenczy, O. F. Wendt, Dalton Trans. 2006, 3934. 4. (a) J. J. R. Frew, M. L. Clarke, U. Meyer, R. P. Tooze, Dalton Trans. 2008, 1976. Tina M. Konrad would like to thank the EU, ITN, NANOHOST, for funding her early stage fellowship.

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Towards Understanding Cocatalyst-Induced Regioselectivity in Industrial Large Scale Toluene Chlorination

Christoph Kring, Franz Windlin, Peter Deglmann, Frank Rominger and Peter Hofmann*

Organisch-Chemisches Institut, Universität Heidelberg INF 270, D-69120 Heidelberg, Germany

[email protected]

Among large scale industrial production processes of organic commodity chemicals catalytic electrophilic arene substitution reactions play an important role, one prominent example being the Lewis acid catalyzed chlorination of toluene with Cl2, which is conducted in commercial plants on a worldwide scale of around 40 to 50 thousand tons per year. As in most aromatic substitution reactions not only reactivity and catalyst activity are crucial issues for industrial applicability, but the regioselectivity - in this case the ratio of o- versus p-chlorotoluene formation - is of high economic relevance as a consequence of a variable market demand for both isomers and of their different downstream chemistry. The desire for a rational control of the o/p isomer ratio of chlorotoluenes has led to the discovery and development of industrially useful, sulphur-based cocatalyst systems (e.g. thioether, S-heterocycles), which allow to shift the product distribution towards the more important and more valuable p-chlorotoluene.

The mode of action of these cocatalysts, however, has remained unclear. We will report the results of a collaborative industrial / academic research project, which - by a combination of mechanistic, synthetic, spectroscopic and quantum chemical (DFT) methods – has provided insight into the details of the catalytic cycle of regioselective, cocatalyzed arene chlorination. The study has revealed the true nature of the catalytically active species as chlorosulfonium ions and has led to the isolation and characterization of representative examples.

Their geometric and electronic structure features, as required for efficient action, will be discussed and a quantum chemistry based high-throughput screening methodology has been developed, which can be employed to search for, to identify and to optimize novel cocatalyst lead structures. We discuss such a novel cocatalyst system, which – according to computational prediction - showed promising p-selectivity, and we compare experimental and theoretical results. [1] F. Windlin, Dissertation, Universität Heidelberg, 2006. [2] Parts of these results were disclosed in plenary lectures: a) P. Hofmann, International Symposium on Catalysis, April 29th 2005, LANXESS, Leverkusen, Germany; b) P. Hofmann, Joint Workshop UC Berkeley, Northwestern U., Univ. Heidelberg, May 6th 2006, Heidelberg, Germany; c) P. Hofmann, Karl-Ziegler-Symposium, Wissenschaftsforum of the German Chemical Society, September 18th 2007, Ulm, Germany.

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A novel amido-iridium catalyst system for the asymmetric hydrogenation of ketones

D. Friedricha, K. Kutleschaa, T. Irrganga,b, R. Kempea,b aUniversity of Bayreuth, Bayreuth, Germany

bAIKAA-Chemicals GmbH, Bayreuth, Germany

The life science industry represents an essential market for the chemical industry. Due to the fact that about 80% of the pharmaceuticals in the product pipeline are chiral and furthermore the FDA is improving the regulations for the launch of chiral pharmaceutical ingredients, there is an increasing demand for optically active intermediates such as amines, alcohols or acids.1 Asymmetric hydrogenation technology provides an excellent access to those substances; the reaction is clean - only utilizing a small amount of catalyst, solvent, substrate and hydrogen.2

Since many chiral ligands are very expensive and/or not readily available,3 the search for new structural motifs, which can be generated easily and are based on simple chiral auxiliaries, plays a fundamental role when expanding asymmetric catalysis to an industrial scale.

Recently we introduced a novel phosphorous free chiral ligand system, which is synthesized by an easy to do one pot bench top chemistry approach, realizing a large variety of substitution patterns. This amido ligand class is able to stabilize transition metals, giving rise to a novel structural type of catalyst, which exhibits high activities and excellent enantioselectivities in the asymmetric hydrogenation of simple ketones.4 Herein the development of this catalyst family is discussed.

OH OH

F

OH

OH

MeO

OH

OH OH OH

Substrate Scope ee >99%:

1 M. Breuer, K. Ditrich, T. Habicher, B. Hauer, M. Keßeler, R. Stürmer, Th. Zelinski, Angew. Chem. Int. Ed. 2004, 43, 788-824. 2 I. C. Lennon, P. H. Moran, Curr. Op. Drug Disc. & Dev. 2003, 6, 855-875. 3 M. Thommen, Speciality Chemicals Magazine 2005, 26-28; H. U. Blaser, F. Spindler, M. Studer, Appl. Catal., A 2001, 221, 119-143. 4 T. Irrgang, D. Friedrich, R. Kempe, PCT/EP 2007 009875.

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NHCP-Ligands for Copper(I) Catalyzed Cyclopropanation?

Erik Kühnel, Patrick Hanno-Igels, Ulrike Blumbach, Igor V. Shishkov, Peter Hofmann*

Organisch-Chemisches Institut, Universität Heidelberg, INF 270, D-69120 Heidelberg, Germany

[email protected]

Copper(I) catalyzed cyclopropanation of olefins with diazo reagents is an issue of great interest1 because cyclopropanes serve as important substructures in organic chemistry. Detailed studies in our group including DFT calculations2, the first experimental detection of neutral copper(I)-carbenes3 and finally their isolation4, has led us to a comprehensive mechanistic understanding of the catalytic cycle and its active species, which had been merely postulated for more than 30 years.

R'

N2

R''

CuR

R''+

R

R'-N2 Using novel, very bulky and electron-rich N-phosphinomethyl functionalized N-heterocyclic carbenes (NHCP), which have been established as versatile chelate ligands for various metals in our group recently5, the properties of strong donor phosphines and NHCs can be combined in one system. The unique steric and electronic features of NHCP have led us to search for cationic copper(I) carbenes with NHCP ligands and to investigate their potential performance in catalytic cyclopropanation.

NN P

R1

R2R3

NHCP ligands Aiming at diastereo- and enantioselective reactions, we are working both on achiral and chiral NHCP ligands. We present our first results related to the coordination chemistry of copper(I) with NHCP ligands as well as our preliminary findings related to the catalytic cyclopropanation of olefins with diazo compounds.

1 a) W. Kirmse, Angew. Chem. 2003, 115, 1120; Angew. Chem., Int. Ed. 2003, 42, 1088; b) A. J. DelMonte, E. D. Dowdy, D. J. Watson, Top. Organomet. Chem. 2004, 6, 97; c) A. Caballero, A. Prieto, M. M. Díaz-Requejo, P. J. Pérez, Eur. J. Inorg. Chem., 2009, 1137. 2 B. F. Straub, I. Gruber, F. Rominger, P. Hofmann, J. Organomet. Chem., 2003, 684, 124. 3 B. F. Straub, P. Hofmann, Angew. Chem. 2001, 113, 1328; Angew. Chem. Int. Ed. 2001, 40, 1228. 4 a) I. V. Shishkov, F. Rominger, P. Hofmann, Organometallics, 2009, 28, 1049; b) I. V. Shishkov, F. Rominger, P. Hofmann, Inorg. Chem. 2008, 47, 11755. 5 a) U. Blumbach, Dissertation, Universität Heidelberg, 2007; b) M. Schmitt, Dissertation, Universität Heidelberg, 2008; c) P. Hanno-Igels, ongoing Dissertation, Universität Heidelberg.

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Immobilization of New Modular Chelating Bisphosphine Ligands for Rh-Catalyzed Hydroformylation of 1-Alkenes

Christoph Larcher, Frank Rominger, Peter Hofmann*

Organisch-Chemisches Institut, Universität Heidelberg, INF 270, D-69120 Heidelberg, Germany [email protected]

Rhodium-catalyzed olefin hydroformylation represents one of the largest volume industrial processes employing homogeneous catalysis. Recently, novel chelating bisphosphine, bisphosphonite and bisphosphite ligands have been developed in our group, featuring a 9,10-bridged-9,10- dihydroanthracene backbone.1

X X

R4

R3R3

R2

R2

R1

R1

= bridging group

X = PR2, P(OR)2, OP(OR)2

These ligands are highly reactive (TOFs > 10.000) in low-pressure, Rh-catalyzed hydroformylation reactions of 1-alkenes and also extremely selective for the desired linear (n) vs. branched (i) aldehyde (n-selectivities > 99%).

We have started to investigate two different approaches towards immobilizing these ligand systems on polymeric supports, and we present our first results of testing their performance in Rh-catalyzed hydroformylation reactions.

1 (a) W. Ahlers, M. Röper, P. Hofmann, D. C. M. Warth and R. Paciello, WO 01/58589, 2001; (b) W. Ahlers, R. Paciello, D. Vogt and P. Hofmann (BASF), WO 02083695 A1, 2002; (c) P. Hofmann, New Catalysts for an Old Reaction: Towards Rational Ligand Design in Hydroformylation, Invited Lecture, 14th International Symposium on Homogeneous Catalysis, Munich, 2004, Abstract IL7.

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Catalytic functionalization of unsaturated species via palladium(IV) intermediates

Johanna M. Larsson, Juhanes Aydin, Nicklas Selander and Kálmán J. Szabó

Department of Organic Chemistry, Stockholm University, SE-106 91, Sweden E-mail: [email protected]

There has been an extensive debate1,2 over whether Heck coupling of aryl iodides with alkenes can proceed via a Pd(II)/Pd(IV) catalytic cycle. Several recent studies indicate that aryl iodides are not able to efficiently oxidize Pd(II) to Pd(IV) and therefore Heck coupling based on a Pd(II)/Pd(IV) cycle can not be realized under usual catalytic condition. However, van Koten3 and Canty4 have shown that stoichiometric oxidative addition of iodonium salts to palladium pincer complexes readily afford palladium(IV) species.

We have now found that palladium pincer complexes as well as palladium acetate can be used as highly active catalysts in Heck-type redox reactions of aryl iodonium salts with functionalized alkenes under mild conditions. The reaction has a broad synthetic scope and tolerates sensitive functionalities such as allylic acetates, silanes and aryl bromides, obtaining highly functionalized products in excellent yields.

According to 31P-NMR spectroscopy, the pincer complex structure remains intact during the catalytic reaction and mercury poisoning does not affect the catalytic activity. This supports the theory that the reaction proceeds via a Pd(II)/Pd(IV) catalytic cycle.

References 1. Sommer, W. J.; Yu, K.; Sears, J. S.; Ji, Y.; Zheng, X.; Davis, R. J.; Sherrill, C. D.; Jones, C. W.; Weck, M. Organometallics 2005, 24, 4351. 2. Eberhard, M. R. Org. Lett. 2004, 6, 2125. 3. Lagunas, M.-C.; Gossage, R. A.; Spek, A. L.; v. Koten, G. Organometallics 1998, 17, 731. 4. Canty, A. J.; Rodemann, T.; Skelton, B. W.; White, A. H. Organometallics 2006, 25, 3996.

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A Model for Catalysis

Ragnar Larsson

Chemical Engineering II, University of Lund P.O. Box 124, SE-221 00 Lund, Sweden

About twenty years ago a model for catalysis was proposed [1]. It was based on the suggestion of a vibrational resonance between a vibration belonging to the catalyst system and that vibration in the reacting molecule that turned the molecule into reaction when excited.The basic idea of the model was that the rate of the reaction was the same as the rate of energy transfer between the two vibrating systems. This rate is calculated from classical physics. From this it was possible to deduce an expression for the so called isokinetic temperature (Tiso) containing both the frequency of the catalyst system (ω) and that of the reacting molecule (ν).

It also followed from the treatment that the activation energy of the reaction was described as the sum of the vibrational quanta of ν. Ea = Σ h ν

Recently this model has been tested on reactions involving benzene derivatives. In case A the hydrodechlorination of chlorobenzene derivatives were studied [2-3]. In case B a series of oxygen-containing derivatives of benzene was similarly studied [4]. Also the hydrogenation of benzene to cyclo-hexane was analyzed; case C [5].

The results were in all cases that the “reacting vibration” was an out-of-plane C-H bending., In the first two cases ν ≈ 720 ± 30 cm-1 and in one case (A [3] ) it was possible to calculate the same value ( 749 cm-1 ) from an analysis of the activation energies.

For A the energy donating vibration was 940 cm-1 (i.e. three quanta of ω interacting with four quanta of ν), for the case B there was a “perfect” resonance, i.e. ω = 750 ± 10 cm-1 (from neutron scattering data [6]). The two different frequencies correspond to two different symmetries of the Ni-H stretch [6]. The question why halo substituted species prefer the higher value and the oxygen substituted prefer the lower of these values is presently unresolved.

For the platinum catalyzed reaction (case C) we found a value of ν ≈ 400 cm-1 which corresponds to a ring – distortion mode. The corresponding ω value was found from an analysis of the frequency dependence of Tiso to be ω ≈ 510 cm-1, corresponding to a Pt-H vibration (i.e. a quantum ratio of 5 : 4).

The model can also be applied to homogeneous catalytic reactions. The reactions of enzymes might be assisted likewise from the infrared radiation of the sheath of bonds surrounding the active center. 1. Larsson R (1989) J Mol Catal 55:70 2. Keane MA, Larsson R (2007) J Mol Catal A Chem 268:87 3. Keane MA, Larsson R (2008) Catal Commun 9:333 4. Keane MA, Larsson R (2009) Catal. Lett. 129; 93 5. Bratlie K.M., Li Y., Larsson R, Somorjai G.A., (2008) Catal. Lett. 121; 173 6. Jobic H, Renouprez A (1984)J Chem Soc Faraday Trans I, 80; 1991

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Synthesis of Naphthopyrans using Montmorillonite K-10 as Catalyst

Z. Lasemi1,2, R. Hosseinzadeh2٭, M. Mohadjerani3 and M. J. Ardestanian2 1Islamic Azad University, Firoozkouh, Iran

2Department of Organic Chemistry, Faculty of Chemistry, Mazandaran University, Babolsar, Iran 3Department of Biology, Faculty of Science, Mazandaran University, Babolsar, Iran

Naphthopyran derivatives are an important class of compounds with excellent photochromic properties1, some of them are also structural motifs present in many biologically active compounds.2 For instance, some naphthopyran derivatives could have potential applications in biochemical research as photoswitch tag compounds.1c Therefore, the synthesis of such compounds has attracted strong interest. There are different methods for the synthesis of naphthopyrans through the condensation of naphthols and propagyl alcohols using para toluene sulfonic acid in solid phase3, acidic alumina in toluene4, para toluene sulfonic acid in the presence of (MeO)3CH as a dehydrating agent5 and catalyzed by indiumtrichloride tetrahydrate under solvent-free ball-milling conditions.6

Herein we report a mild procedure for the synthesis of different naphthopyrans by using Montmorillonite K-10. The yields of products are very good and all products were characterized with specteroscopic methods.

R

OH

Ar'Ar

O

Ar'

ArR

OH

Ar Ar'

R

O

+

R=H, PhAr, Ar'=Ph, Fluorenyl, Ferocenyl

orMontmorillonite K-10

References

1. (a) Hepworth, J. D.; Heron, B. M.. In Progress In Heterocyclic Chemistry; Gribble, G., Joule, J., Eds.; Elsevier: Amsterdam, 2005; Vol. 17, pp 33–62; (b) Nakatsuji, S. Chem. Soc. Rev. 2004, 33, 348; (c) Kumar, S.; Hernandez, D.; Hoa, B.; Lee, Y.; Yang, J. S.; McCurdy, A. Org. Lett. 2008, 10, 3761; (f) Malic, N.; Campbell, J. A.; Evans, R. A. Macromolecules 2008, 41, 1206.

2. (a) Karnik, A. V.; Kulkarni, A. M.; Malviya, N. J.; Mourya, B. R.; Jadhav, B. L. Eur. J. Med. Chem. 2008, 43, 2615; (b) Claessens, S.; Kesteleyn, B.; Van, T. N.; Kimpe, N. D. Tetrahedron 2006, 62, 8419.

3. Tanaka, k.; Aoki, H.; Hosomi, H.; Ohba, S. Org. Lett, 2000, 2, 2133. 4. Gabbut, C. D.; Heron, B. M.; Instone, A. C. Tetrahedron, 2006, 62, 737. 5. Zhao,W.; Carreira, E. M. Org. Lett, 2003, 5, 4153. 6. Dong, Y. W.; Wang, G. W.; Wang, L. Tetrahedron, 2008, 64, 10148

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Metal Catalyst, Lewis Base, and Biocatalyst Working in Concert

Anna Laurell,a Erica Wingstrand,a Linda Fransson,a,b Karl Hultb and Christina Moberga* aKTH School of Chemical Science and Engineering, Organic Chemistry, SE 100 44 Stockholm, Sweden;

bKTH School of Biotechnology, Department of Biochemistry, AlbaNova University Center, SE 106 91 Stockholm, Sweden

Highly enantioenriched O-acylated cyanohydrins are obtained by Lewis acid-Lewis base catalyzed addition of acyl cyanides to prochiral aldehydes (1). The reverse reaction, the enantioselective hydrolysis of the O-acylated cyanohydrin, is catalyzed by Candida antarctica lipase B (CALB) (2). The two processes can be run in parallel in a two-phase system consisting of toluene/buffer (aq). This recycling minor enantiomer one-pot procedure results in close to enantiopure products in high yields. From benzaldehyde for example, the product is obtained in 97% yield and with an er of 99.8:0.2.

R H

O

R' CN

O+

R CN

O

O

R' (1)

(2)R CN

O

O

R' H2OR CN

OH

R CN

O

O

R'

R' OH

O

R CN

O

O

R'

R H

O+ + + HCN

(L*Ti)2, Et3NCH2Cl2

+

(L*Ti)2 =N

N

O

OTi O

2

1. Lundgren, S.; Wingstrand, E.; Penhoat, M.; Moberg, C. J. Am. Chem. Soc. 2005, 127, 11592-11593 2. L. Veum, M. Kuster, S. Telalovic, U. Hanefeld, M. Maschmeyer, Eur. J. Org. Chem. 2002, 1516-1522.

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Metallocene catalyzed polymerization of ethylene in hexane

Won Mook Lee and Chul Woo Lee*

Department of Chemical Engineering, Hanbat National University San 16-1 Dukmyung-dong, Yusung-gu, Daejeon 305-729, Korea

The metallocene catalysts produce the polymers with narrow molecular weight distribution and uniform comonomer content due to a single active site. In commercial polyethylene slurry process, hexane or isopropane is used as a diluent. Therefore the metallocene catalysts should have a good activity in hexane or isopropane in order to use in slurry process. In this paper, we investigate the effect of the hydrogen volume% on the ethylene polymerization activity and moleculer weight with zirconocene catalyst in hexane.

Methylaluminoxane impregnated on silica (SMAO) was used instead of MAO in order to improve the bulk density of polymers. Bis(n-butylcyclopentadienyl)zirconium dichloride (1.0 mg) was activated in hexane (5 mL) with SMAO (160 mg) and then fed into a 1 L reactor containing hexane (700 mL) and triethylaluminum (0.6 mmol). Polymerization was performed by continuous feed of ethylene at 9 bar for 1 h.

The yields and molecular weights and molecular weight distributions (Mw/Mn) of the polymers were in Table 1. Cp2ZrCl2 catalyst, which showed a high activity in toluene, showed very low activity in hexane. Instead, (n-BuCp)2ZrCl2 showed very high activity in hexane. This result is due to the solubility of a catalyst in hexane. Cp2ZrCl2 has a low selectivity in hexane, but has a high solubility in toluene, and (n-BuCp)2ZrCl2 has a high solubility in hexane. Activities increased at low H2 vol%, reaching a maximum at the H2 vol% of 0.8. A decrease of the catalyst activity was observed at high H2 vol%. These trend were not observed in Zigler-Natta catalyst. The molecular weights of the polyethylenes were decreased with incresing H2 vol%. The effect of hydrogen on the molecular weight was larger in the metallocene catalyst than Zigler-Natta catalyst. Therefore it was necessary to control H2 vol% precisely in order to control moleculer weight.

Table1. Results of ethylene polymerization using (n-BuCp)2ZrCl2 catalyst.

H2 (vol%)

Activity (KgPE/gcat/h)

MW x 10-3

MWD (Mw/Mn)

0 149 241.0 2.45 0.18 154 95.1 3.68 0.81 190 12.0 9.35 1.32 152 6.5 9.09 3.33 99 2.9 10.21

References 1. W. Kaminsky and H. Sinn, Adv. Organomet. Chem., 18, 99 (1980). 2. J. M. Vela-Estrada, A. E. Hamielec, Polymer, 35, 808 (1994). 3. K. Soga, T. Arai, H. Nozawa, T. Uozmi, Macromol. Symp., 97. 53 (1995).

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Supported nano-sized iron oxide catalysts for Fischer-Tropsch synthesis

Yun-Jo Lee*, Jo-Yong Park, Jong Wook Bae, and Ki-Won Jun

Petroleum Displacement Technology Research Center, Korea Research Institute of Chemical Technology (KRICT), P.O. Box 107 Yuseong, Daejeon, 305-343, South Korea

To investigate the crystal size effects in the Fischer-Tropsch synthesis (FTS), iron oxide nanocrystals with particle sizes of 2nm to 12nm were synthesized using oleic acid as a capping agent and the supported catalysts of 5wt% Fe/Al2O3 were prepared by the impregnation of δ-alumina (surface area of 127 m2/g) with the colloidal solution of dispersed iron oxide. The synthesized nanocrystals and the supported catalysts were characterized using XRD, TEM, TPR, O2 titration, and CO chemisorption. The FTS performances of the catalysts were examined in a fixed bed reactor. The best results for CO conversion were obtained in the supported catalyst with 6.3 nm iron oxides. With increases in particle size, the C5+ selectivity increases but CH4 and C2-C4 selectivity decreases. Similarly, reduction degree increases but the uptake of adsorbed CO decreases with an increase in particle size. Also, an increase in turnover frequency (TOF) with increasing particle size is considered due to the reduced metal-support interaction by the size effect. Furthermore the nanocrystal-loaded Fe/Al2O3 catalysts prepared from this method exhibited much higher CO conversion and C5+ selectivity than catalysts prepared by conventional method (impregnation).

(a) (b)10 nm

(c) (d)

(e)

Fig. 2. Influence of iron particle size on the TOF. Reaction conditions : T =280 and 300 oC; Pg = 10 kgf/cm2; SV (L/kgcat/h) = 3600; feed compositions (H2/CO/Ar=63.19/31.3/5.51; mol%).* Particle size of Fe is calculated from CO chemisorption data of

the supported catalysts. Fig. 1. TEM images of the size-defined iron oxide: (a) 2 nm, (b) 4.6 nm, (c) 6.3

nm, (d) 9.1 nm, (e) 12.4 nm.

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Iron Nanoparticles as Homogeneous Catalyst for the Hydrogenation of Olefins and Alkynes

Laurent Lefort, Pim Huat Phua, and Johannes G. de Vries

DSM Pharmaceutical Products-Innovative Synthesis & Catalysis, P.O. Box 18, 6160 MD Geleen, The Netherlands


For the hydrogenation of olefins, heterogeneous catalysts such as Pd/C or Ra-Ni are state-of-the-art. Homogeneous catalysis is used only for asymmetric hydrogenation and rarely for simple olefin hydrogenation. Nevertheless, the use of a homogeneous catalyst can have a number of advantages, such as the ability to perform the reaction in a microreactor. Furthermore there is a need for processes based on environmentally friendly and cost-effective metals. For this reason we have started a program for the development of a new cheap homogeneous hydrogenation catalyst based on iron nanoparticles.

R

R'

R

R R'

Fe-

Fe-

Fe-

R

R'

R

R R'

H2

H2

H2

Figure 1. Olefin hydrogenation using iron nanoparticles as catalyst The iron nanoparticles were prepared by reducing FeCl3 with EtMgBr in THF and appeared to be effective for the hydrogenation of a range of olefins and alkynes. Olefin hydrogenation is relatively fast at 5 bar using 5 mol% of catalyst.1 The catalyst is selective for terminal olefins and 1,1’ and 1,2-cis disubstituted olefins. Trans-olefins and tri-substituted olefins react much slower. Alkynes could be hydrogenated to mixtures of alkenes and alkanes. References (1) P.-H. Phua, L. Lefort, J. A. F. Boogers, and J. G. de Vries, Chem. Commun. submitted

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Synthesis of Core@Shell nanoparticles and their application in catalysis

D. Leonarduzzi1,2, P. D. Beer1, P. T. Bishop2, J. Cookson2, B. J. S. Thiébaut2 1Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK 2Johnson Matthey Technology Centre, Blount‘s Court, Sonning Common, Reading, RG4 9NH, UK

email: [email protected]

The investigation of bimetallic (Core@Shell) nanoparticles (whereby metallic nanocrystals are coated/decorated by a layer of a second metal) has gained increasing attention in recent years1,2. This is predominantly due to their unique properties with respect to mono-metallic materials such as distinctive optical properties and enhanced catalytic activity and selectivities. Here, we propose two novel approaches to design core-shell materials using well-defined, and pre-organised “active” precursors.

The first method involves utilising supramolecular (non-covalent) interactions3 between preformed core nanoparticles and a metal complex, in order to form a shell of a second metal (Fig. 1).

Fig. 1. Sandwich route. The Core NP is functionalised in order to interact with an active precursor of the Shell.

With this aim, metallic nanoparticles functionalised with carboxylic functionalities have been prepared using novel and innovative routes. Favourable electrostatic and hydrogen bonding interactions, have been used to associate the particles with a range of shell precursors. These range from simple metallic cations to new ad hoc designed positively-charged bipyridylamide-derivatised palladium and platinum coordination complexes.

The second approach examines a one-step formation of nanoparticles stabilised with a ligand containing a second metal4 (Fig. 2).

Fig. 2. Direct coordination approach. The Shell metal is embedded in the stabiliser of the Core NP.

Subsequent reduction of the resulting nanosystem should yield a bimetallic nanoparticle. So far, the preparation of 1,1′-bis(diphenylphosphino)ferrocene (dppf) stabilised Au, Pd and mixed Au/Pd nanoparticles has been undertaken and the particles tested in hydrogenation reactions. The dppf ligand has been used as an electrochemical probe for the study of the surface properties of the prepared nanosystems. 1 R. Ferrando, J. Jellinek, R. L. Johnston, Chem. Rev., 2008, 108, 845. 2 M.-C. Daniel, D. Astruc, Chem. Rev., 2004, 104, 293. 3 J.-M. Lehn, Angew. Chem., Int. Ed. Engl. 1990, 29, 1304. 4 J. D. E. T. Wilton-Ely, Dalton Trans., 2008, 25.

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Theoretical identification of the interactions between the zeolite framework and the hydrocarbon pool co-catalyst in methanol-to-

olefin conversion

David Lesthaeghe, Veronique Van Speybroeck, Michel Waroquier

Center for Molecular Modeling, Ghent University, Proeftuinstraat 86, B-9000 Ghent, Belgium

The rapidly increasing demand of oil-based chemicals calls for the development of new technologies based on other natural sources. Among these emerging alternatives, the methanol-to-olefin process (MTO) in acidic zeolites is one of the most promising. However, unraveling the reaction mechanism of such an extremely complex catalytic process like MTO conversion has been a challenging task from both experimental and theoretical viewpoint. For over 30 years the actual mechanism has been one of the most discussed topics in heterogeneous catalysis.[1] Instead of plainly following direct routes,[2-3] the MTO process has experimentally been found to proceed through a hydrocarbon pool mechanism, in which organic reaction centers act as homogeneous co-catalysts inside the heterogeneous acid catalyst, adding a whole new level of complexity to this issue.[4-5] Therefore, a more detailed understanding of the elementary reaction steps can be obtained with the complementary assistance of theoretical modeling.

In this work, a complete supramolecular complex of both the zeolite framework and the co-catalytic hydrocarbon pool species is modeled through state-of-the-art quantum chemical techniques [6-7]. This approach provides a more detailed understanding of the crucial interactions between the zeolite framework and its contents, which form the driving forces for successful methanol-to-olefin conversion.

[1] Stocker, M., Microporous Mesoporous Mater. 29, 1999, 3. [2] Song, W.G., Marcus, D.M., Fu, H., Ehresmann, J.O., Haw, J.F., J. Am. Chem. Soc. 124, 2002, 3844. [3] Lesthaeghe, D., Van Speybroeck, V., Marin, G.B., Waroquier, M., Angew. Chem. Int. Ed. 45, 2006, 1714. [4] Dessau, R. M., J. Catal. 99, 1986, 111. [5] Dahl, I.M., Kolboe, S., Catal. Lett. 20, 1993, 329. [6] Lesthaeghe, D., De Sterck, B., Van Speybroeck, V., Marin, G.B., Waroquier, M., Angew. Chem. Int. Ed. 46, 2007, 1311. [7] McCann, D.M., Lesthaeghe, D., Kletnieks, P.W., Guenther, D.R., Hayman, M.J., Van Speybroeck, V., Waroquier, M., Haw, J.F., Angew. Chem. Int. Ed. 47, 2008, 5179.

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Synthesis and catalysis of a novel polymer ionic liquid

Jiamei Liu, Zhen Li*, Jing Chen* and Chungu Xia

State Key Laboratory for Oxo Synthesis and Selective Oxidation, Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, China ,730000. E-mail: [email protected], [email protected]

Recently, the preparation of heterogeneous catalysts by immobilization of functional ILs has become an interesting topic, and has been reported by some researchers.[i, ii] Comparing with conventional ILs, the immobilized ILs has many advantages, such as easily separation from production, reusability, etc.. In this presentation, a novel polymer ionic liquid containing sulfonate unit by crosslinking polymerization was prepared and characterised. The catalysis of ILs for esterification of alcohols with carboxylic acids was also studied. Good conversion rate and high selectivity were obtained, especially for esterification of ethanol with acetic acid. The polymer ionic liquid could be reused after filtration, washed with ether and then dried under vacuum. The results of reaction of esterification were outlined in Table 1. And the TG curves of catalyst unused and used were also outlined in Fig 1. Table 1 Results of esterification catalysed by polymer ionic liquid.a Entry Acid Alcohol acid

/alcohol(mol) Temperature

(℃) Reaction Time (h)

Conv(%)

1 Acetic acid Ethanol 1:2 90 2 80% 2b Acetic acid Ethanol 1:2 90 2 79% 3 Adipic acid Methanol 1:4 90 2 79%

a For all the reactions, the ratio of catalyst to acid was 4wt%. b The catalyst was recycled in the first cycle.

100 200 300 400 500 600 700 800

20

40

60

80

100

TG/%

T/centigrade

Catalyst unused Catalyst used

Fig 1. The TG curves of fresh and the used catalyst.

CH3COOH CH3CH2OH ILs

90� 2hCH3COOC2H5

C5H11COOH CH3OH ILs

90� 2hC5H11COOCH3

[i]D. W. Kim and D. Y. Chi. Angew. Chem., Int. Ed., 2004, 43, 483. [ii]A. Wolfson, I. F. J. Vankelecom and P. A. Jacobs, Tetrahedron Lett., 2003, 44, 1195.

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Computational studies on the catalyzed dehydrogenation reaction of ammonia-borane

Hsin-Yi, Liao*

Department of Science Education, National Taipei University of Education, Taipei City 10659, Taiwan

[email protected]

The dehydrogenation reaction for the ammonia-borane BH3NH3 molecule was examined using the density functional theory (DFT) calculations. The structures were optimized at the B3LYP/aug-cc-PVDZ level of theory. The main interest of this work is to demonstrate that the acidity or basic catalyst can assist in lowering the activation energy of the dehydrogenation reaction of the BH3NH3 molecule. Therefore, the thermodynamic and kinetic stability of BH3NH3 can be adjusted by different catalysts and can also be adjusted stepwisely by the number and orientation of surrounding catalyst molecules.

In addition, the results for the acidic or basic catalysis are compared with the microsolvation effect of the dehydrogenation reaction for the BH3NH3 system. The calculations also show that BH3NH3 can serve as good hydrogen storage systems which release H2 in a slightly exothermic process.

0.000

-7.589(in kcal/mol)

1.002

1.374 1.381

1.587

1.659

1.393

+34.106

BH3NH3

BH2NH2 + H2

Figure 1. Energy profile for the dehydrogenation reaction of BH3NH3. Reference: 1. Dixon, D. A.; Gutowski, M. J. Phys. Chem. A 2005, 109, 5129. 2. Stephens, F. H; Pons, V.; Baker, R. T. Dalton Trans. 2007, 2613.

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Lewis bases in V(v) catalyzed oxygen transfer processes

Silvia Lovat, Cristiano Bindoli, Miriam Mba, Cristiano Zonta and Giulia Licini

Dipartimento Scienze Chimiche, Università di Padova, via Marzolo 1, 35131 Padova, Italy. [email protected]

Oxidation catalyzed by vanadium complexes has been revitalized by the discovery of vanadium dependent enzymes haloperoxidases, producing an ever growing number of studies on biomimetic complexes.1 The main interest has been directed toward oxidations of sulfides, halides, and olefins.2 In the oxidation pathway performed by these complexes it has been largely accepted that the reaction occurs via an electrophilic oxygen transfer process. During the course of these studies, we noticed that the presence in solution of a Lewis base (LB) distinctively enhances the catalytic activity of the systems.3

Si O

O

OR

SiR O

OSi O

SiSiO

OSi

OOSi

R O V

R

R

RRO

O

V

N

O OO

Ot-Bu

t-But-Bu

1 2

S + ROOH SO1 or 2

S= sulfides, olefins, halides, aminesR=H, t-Bu, CMe2Ph

Here we will report on the catalytic activity of V(V) complexes 1 and 2 for efficient and selective activation of hydrogen peroxide and alkyl peroxides. Furthermore, we will report on the LBs capability to selectively modify the catalytic properties of the V(V) complexes via coordination to the metal center. This approach not only offers the opportunity to module reactivity and selectivity of the catalytic systems, but also to better understand the basic principles behind metal activation in synthetic and biological systems. 1. Schneider, C. J.; Penner-Hahn, J. E.; Pecoraro V. L. J. Am. Chem. Soc. 2008, 130, 2712-2713. 2. Mba, M.; Pontini, M.; Lovat, S.; Zonta, C.;. Bernardinelli, G.; Kundig, P.E., Licini, G. Inorg. Chem. 2008, 47,8616-8618. Mba, M.; Zonta, C.; Licini, G. Dalton. Trans. 2009, DOI: 10.1039/b822653a. 3. Lovat, S.; Mba, M.;. Abbenhuis, H.C.L; Vogt,, D.; Zonta, C.; Licini, Inorg. Chem. 2009, 48, DOI: 10.1021/ic802191z.

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Immobilization of Rh-complexes on mesoporous ordered Pd0/Silica for stereoselective hydrogenation reactions

Liguori, F.; a Barbaro, P.;a Dal Santo, V.;b Galarneau, A.;c Ostinelli, L.;b Pirovano, C.;d Psaro,

R.;b Sordelli, L.;b Vizza, F.;a Bianchini, C.a*

a* ICCOM -CNR, IDECAT-CNR Unit, Sesto Fiorentino, Firenze (Italy) b ISTM –CNR,, IDECAT-CNR Unit, Milano (Italy)

c ICGM, IDECAT-CNRS Unit, ENSCM, Montpellier (France) d Dip. CIMA, Università degli Studi di Milano, Milan (Italy)

e-mail address: [email protected]

The stereoselective hydrogenation of di-substituted aromatics is an attractive way to chiral cyclohexyl derivatives. However, to date, few systems were reported to efficiently catalyze this reaction. Molecular rhodium(I) complexes, in either homogeneous phase or supported on silica (RhI/SiO2), perform at low rates unless drastic condition.

The heterogeneous catalysts obtained by the combination of immobilized, cationic diphosphino-RhI complexes and Pd-nanoparticles onto silica (Pd/SiO2) show strong synergistic effects in the hydrogenation of arenes, compared to both RhI/SiO2 and Pd/SiO2.1,2In this work, various preformed chiral RhI-catalysts were immobilized on Pd/SiO2. Ordered and non-ordered silica with different mesopore size and connectivities 3 (MCM-41, MTS, MCM-48, SBA-15, KIT-6, and Davisil LC150) were used for this purpose. The influence of the relative pore and hybrid catalysts shape on their performance in the hydrogenation of aromatic and heteroaromatics was carefully investigated, as well as any possible confinement effect.

1 Barbaro, P.; Bianchini, C.; Dal Santo,V.; Meli, A.; Moreno, M.; Psaro, R.; Sordelli, L. and Vizza, F.; J. Am.

Chem. Soc. 2006, 128, 7065 2 Barbaro, P.; Bianchini, C.; Dal Santo, V.; Meli, A.; Moneti, S.; Pirovano, C.; Psaro, R.; Sordelli, L. and

Vizza, F.; Organometallics, 2008, 27, 2809 3 Di Renzo, F.; Galarneau, A.; Trens, P. and Fajula, F.; Handbook of Porous Materials, Ed. F. Schüth, K. Sing,

J. Weitkamp, Wiley-VCH, 2002, 1311.

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Palladium(II)-Catalyzed Reactions

Jonas Lindh,† Jonas Sävmarker,† Mounir Andaloussi,† Peter Nilsson,† Per Sjöberg§ and Mats Larhed†

Department of Medicinal Chemistry, Organic Pharmaceutical Chemistry, BMC, Uppsala University, Box 574, SE-75123 Uppsala, Sweden. E-mail: [email protected]

§Department of Physical and Analytical Chemistry, BMC, Uppsala University, Box 599, SE-751 23, Uppsala, Sweden

Scope and limitations of the Pd(II)-catalyzed, ligand-promoted oxidative Heck reaction with arylboronic acids have been explored. The arylation proceeded without the presence of a base and with air or p-benzoquinone as reoxidants of Pd(0). Oxidative Heck couplings, employing different arylboronic acids, were smoothly and regioselectively conducted with both electron-rich and electron-poor olefins, providing high yields even with disubstituted butyl methacrylate, sensitive acrolein and a vinylboronate ester. Mild aerobic conditions allowed for the use of substrates sensitive to Pd(II)-catalyzed oxidation. Controlled microwave processing was used to reduce reaction times from hours to minutes both in small scale and in 50 mmol scale batch processes.1

Electrospray ionization mass spectrometry (ESI-MS) and subsequent MS/MS analyses were used to directly detect palladium-containing cationic reaction intermediates in the dmphen-controlled oxidative Heck arylation. The study supports previous mechanistic propositions and provides new information regarding the composition of aryl containing Pd(II) complexes in an ongoing oxidative Heck reaction.2

From earlier experiences in the field of Pd(II)-catalyzed oxidative Heck reactions it occurred to us that it should be possible to produce styrenes from arylboronic acids using low-cost vinyl acetate as the vinylating agent. According to this hypothesis, the reaction would proceed without any addition of base or external palladium reoxidant, since β-acetate elimination should regenerate the active Pd(II). We hereby report the first oxidative Heck-type method for direct synthesis of styrenes from arylboronic acids or aryltrifluoroborates together with ESI-MS and MS/MS analyses of palladium-containing reaction intermediates. The findings support a Pd-mediated release of free ethylene which subsequently undergoes arylation, providing the styrene product.3

The first Pd(II)-catalyzed P-arylation was performed using palladium acetate, dmphen (2,9-dimethyl-1,10-phenanthroline), and without addition of base or acid. Couplings of arylboronic acids or aryltrifluoroborates with H-phosphonate dialkylesters were conducted in 30 min with controlled microwave heating under non-inert conditions. The excellent chemoselectivity of the method was illustrated in the synthesis of a MTB enzyme glutamine synthestase inhibitor. Online electrospray ionization mass spectrometry (ESI-MS) was used to directly detect cationic palladium species in ongoing reactions.4

(1) Lindh, J.; Enquist, P. A.; Pilotti, A.; Nilsson, P.; Larhed, M.; J. Org. Chem. 2007, 72, 7957-7962. (2) Enquist, P. A.; Nilsson, P.; Sjöberg, P. J. R.; Larhed, M.; J. Org. Chem. 2006, 71, 8779-8786. (3) Lindh, J.; Sävmarker, J.; Nilsson, P.; Sjöberg, P. J. R.; Larhed, M.; Chem. Eur. J. 2009, 15, 4630-4636. (4) Andaloussi, M.; Lindh, J.; Sävmarker, J.; Sjöberg, P. J. R.; Larhed, M., Manuscript in preparation.

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Novel biofuels integrating glycerol via transesterification of sunflower oil catalysed by covalently immobilised pig pancreatic

lipase

Diego Lunaa*, Verónica Caballeroa, Felipa M. Bautistaa, Juan M. Campeloa, Rafael Luquea, Jose M. Marinasa, Antonio A. Romeroa, Jose M. Hidalgob, Anastacia Macarioc,

Girolamo Giordano aDepartamento de Química Orgánica, Universidad de Córdoba, Campus de Rabanales, Edificio. Marie Curie,

E-14014 Córdoba, Spain. bSeneca Green Catalyst, S.L. Campus de Rabanales, 14014-Córdoba, Spain.

cDip. Ing. Chim. & Mat., Università della Calabria, I-870366 Rende (CS), Italy. *Fax: (+34)957212066

E-mail: [email protected]

We report a methodology to prepare novel biofuels that integrate glycerol in their composition using covalently immobilised Pig Pancreatic Lipase (PPL). Activated AlPO4 was employed as support for the covalent immobilization of PPL after functionalisation with p-hydroxybenzaldehyde (Figure 1) [1].

Figure 1. Immobilization of the enzyme PPL through the ε-amino group of lysine residues.

The biocatalyst was found to be strongly fixed to the inorganic support (94.3%). Quantitative conversions of triglycerides (TG) and high yields to fatty acid ethyl esters (FAEE) were obtained under mild reaction conditions. All investigated reactions with free or immobilized PPL provided yields inferior to 66% that correspond to the transformation of TG in a mixture of two moles of FAEE and a mole of glycerides, consistent with the high 1,3-regioselectivity towards more reactive 1 and 3 positions in the triglyceride reported using various lipases [2, 3]. The immobilised catalyst was highly reusable preserving most of its initial activity after 42 runs, and the reaction mixture was easily separated by decantation. References [1] a) D. Luna, F.M. Bautista, A. Garcia, J.M. Campelo, J.M. Marinas, A.A. Romero, A. Llobet, I. Romero, I.

Serrano. PCT WO 2004/096442, 2004; b) F.M. Bautista, V. Caballero, J.M. Campelo, D. Luna, J.M. Marinas, A.A. Romero, I. Romero, I. Serrano, A. Llobet, Top. Catal. (2006), 40, 193-205.

[2] Bornscheuer UT. Lipase-catalyzed syntheses of monoacylglycerols. Enzyme Microb Technol (1995); 17: 578-586.

[3] Bornscheuer, U.T. Enzyme Microb. Technol. 17 (1995) 578-586

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Dynamic Kinetic Resolution of 2-Hydroxy-1-Indanone with Heterogeneous Catalysts

O. Långvik,a,d T. Saloranta,a A. Liljeblad,c A. Kirilin,b P. Mäki-Arvela,b L. T. Kanerva,c D. Yu. Murzinc and R. Leinoa

a Laboratory of Organic Chemistry and b Laboratory of Industrial Chemistry, Åbo Akademi University, Biskopsgatan 8, FIN-20500 Åbo

c Laboratory of Synthetic Drug Chemistry University of Turku, Lemminkäisenkatu 5C, FIN-20250 Turku d Graduate School of Materials Research, Turku, Finland

The development of new processes with high yields and selectivities combined with minimum waste generation and energy consumption is one of the key issues in modern chemistry. One way to reach these goals is to utilize dynamic kinetic resolution (DKR) processes by combining highly selective and active metal and enzyme catalysts. Such DKR processes provide several advantages over traditional manufacturing methods. In the best case of a lipase-catalyzed kinetic resolution, only one stereoisomer reacts, resulting in an enantiopure product with the maximum yield of 50 %. By applying a DKR process, where the racemization of the starting material during the kinetic resolution takes place, the theoretical yield of 100 % may be obtained, leaving no unconverted starting material.

slowkB

O

OH

O

OH

SR

SS

k inv k inv-1

fastkA

O

O

O

PS

O

O

O

PR

Enantiopure 2-hydroxy-1-indanone is a precursor utilized in the production of 1-amino-2-indanol which is a useful chiral building block.1 In the ongoing work, we have investigated different heterogeneous racemization catalysts that can be applied in the DKR of 2-hydroxy-1-indanone. Satisfactory results were not achieved with various basic or acidic ion exchangers. Metal catalysts, such as copper and ruthenium, supported on Al2O3, are capable of racemizing the vicinal hydroxyl ketone moiety in an effective and selective manner.2,3 Herein, we present the results obtained in a heterogeneously catalyzed DKR. The product was obtained with an enantiomeric excess up to 96 % at a 64-74 % conversion within a 5 h reaction time at 37-39 °C.

1 a) Vacca, J. P. et. al. Proc. Natl. Acad. Sci. 1994, 91, 4096; b) Liu, S.; Wolf, C. Org. Lett. 2008, 10, 1831; c)

Struble, J. R.; Kaeobamrung, J.; Bode, J. W. Org. Lett. 2008, 10, 957; d) Senanayake, C. H. Aldrichim. Acta 1998, 31, 3.

2 Zaccheria, F.; Ravasio, N.; Psaro, R.; Fsui, A. Chem. Eur. J. 2006, 12, 6426 3 a) Yamaguchi, K.; Mizuno, N. Angew. Chem. Int. Ed. 2002, 41, 4538 (b) Yamaguchi, K.; Mizuno, N.

Angew. Chem. Int. Ed. 2003, 42, 1480 (c) Yamaguchi, K.; Mizuno, N. Chem. Eur. J. 2003, 9, 4353.

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Switchable ferrocenyl phosphines as precursors for immobilized catalysts

Martyna Madalska, Evamarie Hey- Hawkins*

Universität Leipzig, Institute of Inorganic Chemistry, Johannisallee 29, 04103 Leipzig; Germany

The class of ferrocenyl phosphines has grown over the last decade, because many of these compounds were found to be excellent ligands for transition metals in homogeneous catalysis.1 We have already developed high-yield syntheses for enantiopure chiral ferrocenyl phosphines and shown that the Fe2+ center is selectively and reversibly oxidizable.2

Recently, a new type of phosphines has been synthesized, namely, potentially switchable phosphines in which one group is UV/Vis-, pH-, or redox-active, which seem suitable for modifying the catalytic properties of the corresponding transition metal phosphine complexes in situ, that is, changing their activity and selectivity. Using 1,1’,2-substituted ferrocenyl derivatives will allow introduction of planar chirality besides C- or P-chiral centers as well as an anchor group R’ (R’= -CH=CH2, -SH, -Si(OMe)3) on the second cyclopentadienyl ring, which can be used for grafting the ligands onto surfaces.3

FePR1

R2

R

R

Figure 1 The R’-substituted phosphines and complexes thereof with transition metals (Rh, Ru, Pd) will be prepared and grafted onto suitable surfaces (gold, carbon, polymers, etc.), and their catalytic reactions (asymmetric hydrogenation, asymmetric hydroformylation, and C-C coupling) will be studied.

The immobilized switchable catalysts may offer a new approach to this field. Therefore, these chiral multicenter catalysts are already highly interesting in their own right.

1 T.J. Colacot, Chem. Rev. 2003, 103, 3101 2 S. Tschirschwitz, P. Lönnecke, E. Hey-Hawkins, Organometallics 2007, 26, 4715; R. Kalio, P. Lönnecke, E. Hey-Hawkins, J. Organomet. Chem. 2008, 693, 590; S. Tschirschwitz, Dissertation, Universität Leipzig, 2007 3 P. Štěpnička, Ferrocenes. Ligands, Materials and Biomolecules, Wiley 2008

R= -CH2NMe2, -CHMeNMe2 R1= R2 or R1≠ R2 R’= anchoring group

'

Fe

PR1

R2

R

R'

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Enantioselective hydrogenation of indole derivatives catalyzed by Walphos/rhodium complexes

Anna M. Maj, Isabelle Suisse, Catherine Méliet, Francine Agbossou-Niedercorn*

Université Lille1 Sciences et Technologies, Unité de Catalyse et de Chimie du Solide UMR 8181, ENSCL(CHIMIE), Bât C7, BP 90108, 59652 Villeneuve d’Ascq Cedex France


The enantioselective hydrogenation of heteroaromatic compounds constitute a very powerful tool to access chiral cyclic skeletons with high potential for asymmetric synthesis.[1,2] Still, the hydrogenation of heteroatomic compounds has been less investigated than other classes of substrates like enamides, β-keto esters, imines, and other olefins.[3] If quinoline, quinoxaline, and pyridine compounds have been reduced with excellent selectivities,[1,2] five membered heteroaromatic compounds, such as indole derivatives, have been hydrogenated efficiently only in the presence of the non-commercially available trans-chelating bisphosphines of the Ph-TRAP family.[4]

NCOOR

BocN

COOR

Boc

H

1a R = Me1b R = Et1c R = tBut

Rh-complexWalphos Ligand

H2Cs2CO3

2a R = Me2b R = Et2c R = tBut

MeOH

Here, we report a new efficient catalytic system based on rhodium complexes and chiral bisphosphines of the Walphos family for the enantioselective hydrogenation of 2-substituted indole derivatives, ee’s up to 85% have been obtained.[5] ________________________ [1] F. Glorius, Org. Biomol. Chem. 2005, 3, 4171-4175. [2] Y.-G. Zhou, Acc. Chem. Res. 2007, 40, 1357-1366. [3] a) Catalytic Asymmetric Synthesis; Ojima, I., Ed., 2nd ed.; Wiley-VCH: New York, 2000; b)

Comprehensive Asymmetric Catalysis; Jacobsen, E. N., Pfaltz, A., Yamamoto, H., Eds.; Springer: Berlin, 1999; c) R. Noyori, T. Ohkuma, Angew. Chem. Int. Ed. 2001, 40, 40-73; d) H. U. Blaser, C. Malan, B. Pugin, F. Spindler, H. Steiner, M. Studer, Adv. Synth. Catal. 2003, 345, 103-151.

[4] For rhodium based hydrogenation of indoles, see: a) R. Kuwano, K. Sato, T. Kurokawa, D. Karube, Y. Ito, J. Am. Chem. Soc. 2000, 122, 7614-7615; b) R. Kuwano, K. Kaneda, T. Ito, K. Sato, T. Kurokawa, Y. Ito, Org. Lett. 2004, 6, 2213-2215; c) R. Kuwano, M. Kashiwabara, K. Sato, T. Ito, K. Kaneda, Y. Ito, Tetrehedron: Asymmetry 2006, 17, 521-535; d) R. Kuwano, M. Sawamura, Y. Ito, Bull. Chem. Soc. Jpn. 2000, 73, 2571-2578; for ruthenium and iridium based hydrogenation of indoles, see e) R. Kuwano, M. Kashiwabara, Org. Lett. 2006, 8, 2653-2655.

[5] A. M. Maj, I. Suisse, C. Méliet, F. Agbossou-Niedercorn manuscript submitted.

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Palladium-Catalyzed γ-Selective and Stereospecific Allyl–Aryl Coupling between Allylic Acetates and Arylboronic Acids

Yusuke Makida, Masahito Tanabe, Hirohisa Ohmiya and Masaya Sawamura*

Department of Chemistry, Faculty of Science, Hokkaido University

Transition metal-catalyzed allylic substitution reactions with carbon nucleophiles are powerful carbon–carbon bond formation methods because of their broad substrate scopes under mild reaction conditions. Here we present a new palladium-catalyzed allylic substitution methodology, which allows for the reaction of allylic acetates with arylboronic acids with high γ-selectivity and E/Z-selectivity.[1] The reaction of optically active allylic acetates having an α-stereogenic center took place with excellent α-to-γ chirality transfer with syn-selectivity, and gave the corresponding optically active allyl–aryl coupling products with a stereogenic center at the benzylic position.

The reaction of allylic acetate 1a with phenylboronic acid in the presence of catalytic amounts of Pd(OAc)2, 1,10-phenanthroline, and AgSbF6 in 1,2-dichloroethane at 60 ˚C for 6 h afforded allyl–aryl coupling product 2a in 80% isolated yield with complete regio- (2a/2a’ 100:0) and E/Z- (>20:1) selectivities. Conversely, the reaction of 1a’ afforded 2a’, an isomer of 2a with regard to the α/γ-regioselectivity, with complete regio- (2a/2a’ 0:100) and E/Z- (>20:1) selectivities. Notably, the palladium-catalyzed allylic substitution can be performed even under air without affecting the product yield and the selectivities.

Ph

OAc

NN1,10-phenanthroline (phen)

Phα γ

α γ

80% (91% conv) 2a/2a' 100:0; E /Z >20:1

1aPd(OAc)2 (10 mol %)1,10-phen (12 mol %)AgSbF6 (10 mol %)1,2-dichloroethane60 ÞC, 6 h

2a

Ph γ α1a'

OAc

Ph γ α

48% (68% conv) 2a/2a' 0:100; E /Z >20:1

2a'

B(OH)2+

B(OH)2+

(1.5 equiv)

(1.5 equiv)

The allyl–aryl coupling with α-chiral allylic acetates took place with perfect α-to-γ chirality transfer with syn-selectivity. The reaction of (R)-(E)-1b (98% ee) having a non-protected hydroxyl group with phenylboronic acid gave (S)-(E)-2b with 98% ee in 63% isolated yield.

[1] Ohmiya, H.; Makida, Y.; Tanaka, T.; Sawamura, M. J. Am. Chem. Soc. 2008, 130, 17276–17277.

OAc

(R)-(E)-1b (S)-(E)-2b

Pd(OAc)2 (10 mol %)2,2'-bipyridyl (12 mol %)AgSbF6 (10 mol %)

1,2-dimethoxyethane 60 °C, 6 h

γ/α >99:1; E/Z >20:198% ee 63%, 98% ee

B(OH)2+

(1.5 equiv)

HO HO

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Dendrimer Encapsulated Metal Particles as Catalysts for Organic Transformations

Selwyn F. Mapolie, Mteteleli A. Sibaca

Department of Chemistry and Polymer Sciences, Stellenbosch University, South Africa

Dendrimers are multi-branched molecules with evenly distributed and well-defined three-dimensional shapes. Dendritic molecules often adopt a globular structure with regular sized cavities within the macromolecule, especially those of higher generation [1]. These three-dimensional cavities within the macromolecule allow the dendrimer to act as suitable hosts for small guest molecules and metal particles. In some cases dendrimers have been viewed as potential nano-reactor systems. These cavities within the dendrimeric framework have recently been exploited in the production of metal nanoparticles with the dendrimers acting as stabilizing agents [2]

M = Rh, Pd

Figure 1: Procedure for producing metal encapsulated metal particles.

Over the last couple of years we have been studying the production of new dendrimeric molecules with the aim of using these as stabilizing agents for metal nanoparticles. Our focus has largely been on polypropyleneimine (PPI) dendrimers containing a range of different peripheral functionalities. In this paper we report on the production of Pd and Rh nanoparticles stabilized by PPI dendrimers modified by alkyl ester functionalities as well as aromatic amide units on the periphery. These dendrimer-encapsulated nanoparticles were characterized by techniques such as UV spectroscopy, TEM and ICP-AES. The effect of the the nature of the peripheral groups of the dendrimer on the stability of the nanoparticles was studied. Some of these dendrimer encapsulated nanoparticles were evaluated in different catalytic transformations of organic substrates. Thus for example the dendrimer encapsulated metal particles (DEMP’s) based on Pd were evaluated in C-C coupling reactions (Heck and Suzuki coupling), while the Rh systems were evaluated in olefin hydrogenation reactions. In several cases the encapsulated catalysts were found to be more active than molecular catalysts based on the same metals even at significantly lower metal loadings. In addition the DEMP based catalysts can be separated from reaction mixtures via ultra-filtration and then be re-used without significant loss in activity. References; [1] Klajnert, B; Bryszewska, M. Acta Biochemica Polanica., 1990, 48, 199.

[2] R.M. Crooks, M.Q. Zhao, L. Sun, V. Chechik, L.K. Yueng, Acc. Chem. Res., 2001, 34, 181

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New Immobilized Ligands for Catalysed Transfer Hydrogenation Reaction

Yvette A. Mata, Giménez- Pedrós Marta and Piet. W. N. M. van Leeuwen

Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona, Spain,

The growing demand for enantiomerically pure compounds for the development of pharmaceuticals, agrochemicals and flavors has captured the interest of the chemist in the last few decades. Enantioselective homogeneous metal catalysis is an attractive method for producing enantiopure compounds. [1] The enantioselective synthesis of chiral secondary alcohols by catalytic reduction of the corresponding ketone is an important class of intermediates for the industry. The reduction of ketones using homogeneous catalysts for hydrogen transfer, with 2-propanol as hydrogen source, has been investigated extensively in recent years [2], but only few immobilized homogeneous catalysts have been reported. The use of immobilized catalysts can provide a significant improvement over the homogeneous process to overcome the problems of separation and recycling of the catalyst. Silica is the most common support for the heterogenization for its high stability, inertness and low cost. [3] Over the past decade, interest in miniaturisation of chemical reactions has rapidly grown [4]. Microflow reactors have received significant interest in the stream of downsizing of chemistry and they are expected to make an innovative change for chemical synthesis [5]. In this work, we present the synthesis and the application of silica-anchored ligands and complexes in the asymmetric transfer hydrogenation reaction. The reaction was studied in conventional batch systems and in microreactors ( Figure 1).

Figure 1. Microreactor for heterogeneous catalysis (V= 1ml) A, B: microreactor inlets

References: [1]P. W. N. M. van Leeuwen “Homogenous Catalysis: Understanding the Art”, Kluwer, Dordrecht, 2004 [2]Gladiali, S., Alberico, E. Chem. Soc. Rev. (2006), 35, 226 [3] Albertus J. Sandee, Daniëlle G. I. Petra, Joost N. H. Reek, Paul C. J. Kamer, Piet W. N. M. van Leeuwen Chem. Eur. J. (2001), 7, 1202; Del Zotto A., Greco C., Baratta W., Rigo P. Eur. J. Inorg. Chem (2007), 2909. [4] Ehrfeld , W., Hessel, V., Löwe, H. “Microreactors: New Technology for Modern Chemistry”, Wiley-VCH, Weinheim 2000 [5] Manz, A., Becker, H. Eds. “Microsystem Technology in Chemistry and Life Sciences”; Springer, Berlin, 1999

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Palladium Nanoparticles in Allylic Alkylations and Heck Reactions: The Molecular Nature of the Catalyst Studied in a

Membrane Reactor

Javier Mazuelaa, Montserrat Diégueza*, Oscar Pàmiesa, Yvette Mataa, Emmanuelle Teumab, Montserrat Gómezb*, Fabrizio Ribaudoc, Piet W. N. M. van Leeuwenc,d*

a Departament de Qumíca Física i Inorgànica. Universitat Rovira i Virgili. Campus Sescelades, C/Marcel·lí Domingo, s/n. 43007 Tarragona, Spain, Fax: (+34)-97-755-9563; e-mail: [email protected]

b Laboratoire Hétérochimie Fondamentale et Appliquée, UMR CNRS 5069. Université Paul Sabatier. Bât 2R1, 2ième étage, 118, route de Narbonne. 31062 Toulouse cedex 9, France, Fax: (+33)-56-155-8204; e-mail:

[email protected] c van't Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018

WVAmsterdam, The Netherlands, Fax: (+34)-97-792-0224; e-mail: [email protected] d Institute of Chemical Research of Catalonia (ICIQ), Av. Països Catalans 16, 43007 Tarragona, Spain

An important application of metallic nanoparticles (MNPs) may be found in catalysis because of their large surface area and concomitant higher potential activity and because their reciclability, both of which represent a breakthrough at the frontier between homogeneous and heterogeneous catalysis.1 In this context, MNPs have proven to be efficient and selective catalyst for several types of catalytic reactions, such as olefin hydrogenation and C-C coupling.2 An important research target in asymmetric catalysis using MNP2 is to learn whether or not the MNPs are responsible for the catalytic activity, or that molecular species leached from the MNP are the actual catalyst.3

Here, we describe the use of sugar-based oxazolinyl-phosphite ligands as new type of stabilizers for PdNPs and theirs application in the enantioselective Pd-catalyzed allylic substitution and Heck coupling reactions. We also present a detailed study to provide conclusive evidence of the nature of the species involved in the catalytic reaction in liquid phase by introducing the use of a continuous-flow membrane reactor (CFMR), combined with TEM observations, classical poisoning and kinetic measurement experiments. The use of continuous-flow membrane reactor (CFMR) has been crucial to elucidate the true nature of the catalyst.

1 See for instance: a) El-Sayed, M. A. Acc. Chem. Res. 2001, 34, 257. b) Bönnemann, H.; Richards, R. M. Eur.

J. Inorg. Chem. 2001, 2455. c) Astruc, D.; Fu, F.; Aranzaes, J. R. Angew. Chem. Int. Ed. 2005, 44, 7852. d) Migowski, P.; Dupont, J. Chem. Eur. J. 2007, 13, 32.

2 See for instance: a) Studer, M., Blaser, H.-U.; Exner, C. Adv. Synth. Catal. 2003, 345, 45. b) Bönnemann, H.; Braun, G. A. Angew. Chem. Int. Ed. Engl. 1996, 35, 1992. c) Tamura, M.; Fujihara, H. J. Am. Chem. Soc. 2003, 125, 15742. d) Jansta, S.; Gómez, M.; Philliot, K.; Muller, G.; Guiu, E.; Claver, C.; Castillón, S.; Chaudret, B. J. Am. Chem. Soc. 2004, 126, 1592. e) Favier, I.; Gómez, M.; Muller, G.; Axet, M. R.; Castillón, S., Claver, C; Jansat, S.; Chaudret, B.; Philipot, K Adv. Synth. Catal. 2007, 349, 2459.

3 See for instance: a) Phan, N. T. S; van der Sluys, M.; Jones, C. W. Adv. Synth. Catal. 2006, 348, 609. b) de Vries, J. G. Dalton Trans. 2006, 421. c) Chinchilla, R.; Nájera, C. Chem. Rev. 2007, 107, 874. d) Dúran Pachón, L.; Rothenberg, G. Appl. Organomet. Chem. 2008, 288.

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Inducing Selective Chemistry on Metal Surfaces: Stereoselection on Platinum and Olefin Metathesis on Mo2C

Peter H. McBreen, Stéphane Lavoie, Vincent Carpentier-Demers, Marc-André Laliberté, Nathalie Dubuc, Jean Brunelle and Mohamed Siaj.

Département de chimie, Université Laval, Québec (Qc), Canada, G1K 7P4

Approaches for inducing selective organic transformations in heterogeneous catalysis will be described using the examples of asymmetric hydrogenation on Pt and olefin metathesis on Mo2C. The enantioselective hydrogenation of activated ketones on chirally-modified supported Pt is known as the Orito reaction. Enantioselection arises from the adsorption geometry and the substrate activation imposed by the combined chiral-modifier/substrate/metal surface interaction. When examined in the context of the catalysis literature, surface science measurements, using STM and RAIRS, help to reveal the set of chemical forces leading to the formation of the activated prochiral complex. One of the most interesting facets of the reaction is the observation of rate-enhancement on the chirally-modified surface with respect to the rate of the racemic reaction on the non-modified surface. Studies of a range of substrates on Pt(111) will be presented and the results will be discussed within the context of literature data for rate-acceleration and enantioselection. Olefin metathesis on surfaces requires the formation of terminal surface alkylidene (M=CR1R2) initiator sites. However, the formation of bridged alkylidenes is strongly favored on pure metal surfaces. In contrast, we find that metathesis active alkylidene sites may be formed and studied on the surface of molybdenum carbide.

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Biphasic hydrogenation of α−β unsaturated aldehydes using water-soluble binuclear rhodium complexes

Luis G. Meleana, Merlín Rosalesb and Pablo J. Baricelli*a

a Centro de Investigaciones Químicas, Facultad de Ingeniería, Universidad de Carabobo, Valencia, Venezuela. Email: [email protected]

b Laboratorio de Química Inorgánica, Departamento de Química, Facultad Experimental de Ciencias, Universidad del Zulia Maracaibo, Venezuela

The water soluble complexes [Rh(CO)(Pz)(TPPMS)]2 and [Rh(CO)(Pz)(TPPTS)]2, Pz = pyrazolate, TPPMS = (C6H5)2P(C6H4SO3Na) y TPPTS = P(C6H4SO3Na)3, [1, 2] were evaluated as catalytic precursors in the biphasic hydrogenation of aldehydes α−β unsaturated (cinnamaldehyde, 2-methyl cinnamaldehyde, crotonaldehyde and citral) and the corresponding saturated aldehydes were obtained with high selectivities (85-90%). The optimal reaction conditions were determined using eugenol as the model substrate by varying the temperature (60 to 100 ºC), the H2 pressure (200 to 800 PSI), the substrate/catalyst relation (250:1 to 1500:1) and the concentration of CTAC (0 to 0,1 M). Under the best reaction conditions (70 ºC, 300 PSI H2, S/C = 500:1, [CTAC] = 0,05M) the reactivity order was as follows: crotonaldehyde > cinnamaldehyde > 2-methyl cinnamaldehyde > citral. The reactions with the complex bearing the trisulphonated phosphine gave better activity and selectivity towards the saturated aldehydes than the reactions with the monosulphonated phosphine, which is explained by the higher solubility in water of the TPPTS compared to the TPPMS. Since the ease of recycling of the catalyst is one of the advantages of biphasic systems, the reuse of the aqueous catalytic phase was studied. It was found that under anaerobic conditions, the catalytic activity remains almost constant after five consecutive cycles and the selectivity towards the saturated aldehydes does not diminish.

______________ References: 1. Baricelli, P. J.; López-Linares, F.; Bruss, A.; Santos, R. ; Lujano, E.; Sánchez-Delgado, R. A. J. Mol. Catal. A: Chemical 2005, 239, 130-137. 2. Pardey, A. J.; Fernández, M.; Moreno, M. A.; Alvarez, J.; Rivas, A. B.; Ortega, M. C.; Méndez, B.; Baricelli, P. J.; Longo, C. React. Kinet. Catal. Lett. 2000, 70, 293.

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Towards the Dynamic Kinetic Asymmetric Transformation of 1,3-aminoalcohols

Renaud Millet, Annika Träff, and Jan-E. Bäckvall*

Organic Chemistry Departement, Stockholm University, Arrhenius labotatory, SE-10691 Stockholm, Sweden

The combined metallo- enzymatic catalyzed dynamic kinetic resolution (DKR) of secondary alcohol or amine is now a useful and well known process. This process can be extended to more than one stereocenter to obtain diastereomerically and enantiomerically pure compound. Such process is named dynamic kinetic asymmetric transformation (DYKAT).

Recently our group described the DYKAT of various diols. In order to extent this work we get interested in aminoalcohols and especially 1,3-aminoalcohols1 (Scheme 1).

R1

NH

R2

OH Ru catalystenzymeAcyl donor R1

NAc

R2

OAc

Scheme 1: DYKAT of 1,3 amino-alcohols

Epimerization of both alcohol and amine is performed by a ruthenium based catalyst. At the same time, the alcohol will be acetylated by an enzyme and acetylation of the amine should occur via intramolecular acyl transfer (Scheme 2).

R1 R2

NH O

O

R1 R2

N O

Me OH

NMe

OHO

MeR1

R2

R1 R2

NH O

O

R1 R2

N O

Me OH

NMe

OHO

MeR1

R2

Scheme 2: Acyl transfer

This acyl transfer should occur preferentially on the syn diastereomer yielding the enantiopure syn aceto-amide.

1 M. Edin, J. Steinreiber, and J. E. Bäckvall Proc. Natl. Acad. Sci. USA, 2004, 101, 5761-5766.

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A DFT Study on the Multiple C-H Bond Activation Mechanism in Ethers with [TpMe2Ir(III)]

S. Moncho1, G. Ujaque1, A. Lledós1, P. Lara2, M. Paneque2, M.L. Poveda2, E. Carmona2

1Unitat de Química Física, Departament de Química, Universitat Autònoma de Barcelona. 08193 Bellaterra (Barcelona), Spain 2Instituto de Investigaciones Químicas, Dep. de Química Inorgánica. CSIC-Universidad de

Sevilla. 41092 Sevilla, Spain

One of the most active and important fields in catalysis is formation and cleavage of bonds involving carbon atoms. It is of special relevance to perform the direct functionalization of C-H bonds in simple organic molecules and the C-C bond formation, avoiding activated reactants, usually expensive and pollutant.[1]

Carmona and coworkers have performed an extensive work in the CH activation on ethers with hydrotris(pyrazolyl)borate iridium(III) complexes.[2,3] The high reactivity of these complexes has been described, including multiple C-H bond activations in alkyl and alkylaryl ethers, as well as C-O cleavage and C-C formation.

o Scheme 1: Triple activation

f anisole with [TpMe2Ir(III)]

We have performed a computational study on the mechanism of the triple activation of anisole using [TpMe2IrPh2] (Scheme 1).[3] In this reaction one arylic and two methylic C-H bonds are activated and a carbene and aryl ligand is formed.[4] Two main pathways are studied depending whether the first activation takes place in an arylic or alkylic C-H bond. Theoretical calculations reveal the relevant intermediacy of σ-C-H complexes in a σ-CAM mechanism.

[1] Murai, S. (Ed.) Activation of Unreactive Bonds and Organic Synthesis Springer: Berlin, 1999. [2] Paneque, M.; Poveda, M.L.; Santos, L.L.; et al Angew. Chem. Int. Ed. 2004, 43, 3708-3711 [3] Alvarez, E.; Paneque, M.; Petronilho, A.G.; et al Organometallics 2007, 26, 1231-1240 [4] Lara, P.; Paneque, M.; Poveda, M.L. et al , V. Chem. Eur. J. Accepted. [5] Carmona, E.; Paneque, M.; Santos, L.L.; Salazar, V. Coord. Chem. Rev. 2005, 249, 1729-1735.

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Allylsilylation of Aromatic and Aliphatic Alkenes with Allyltrimethylsilane over H+-Montmorillonite

as a Solid Acid Catalyst

Ken Motokura, Shigekazu Matsunaga, Akimitsu Miyaji and Toshihide Baba*

Tokyo Institute of Technology, Interdisciplinary Graduate School of Science and Engineering, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8502, JAPAN

Allylsilylation of alkene is a direct method to introduce both silyl and allyl groups to a carbon-carbon double bond (Eq. 1).

R1 +R1

catalystSiR'3

SiR'3R2

R2

(1)

The reaction of aliphatic alkenes using aluminum chloride as a homogeneous catalyst is

currently only one example of allylsilylation.[1] Formation of cationic Me3Si species as an intermediate was proposed in the allylsilylation with allyltrimethylsilane.[1]

It is well known that allylsilanes can react with silanol groups (Si-OH) on silica to form surface oxysilane species (Si-O-SiR3) and propylene.[2] These facts encouraged us to attempt a generation of cationic silane species on solid protonic acid surface by the reaction between H+ site and allylsilane. If the R3Si+-like species forms, the catalytic allylsilylation should be proceed. In this work, allylsilylation of alkenes was examined using heterogeneous and homogenous protonic acids.

Allylsilylation of p-chlorostyrene (1a) with three equivalent of allyltrimethylsilane (2a) was carried out at 100 oC for 30 min. The results are shown in Table 1. The selection of catalyst is crucial. H+-montmorillonite showed a high catalytic performance to give (2-(4-chlorophenyl)-pent-4-enyl)trimethylsilane (3a) with 85% yield based on 1a. The product did not form with Na+-montmorillonite. H+-exchanged zeolites, such as USY were less active, while other solid acids, mesoporous silica FSM-16 and Amberlyst, were inactive. The reaction did not proceed with p-toluenesulfonic acid and H2SO4. We will also present reactions of various alkenes and spectroscopic analysis of active Si species on solid acid surfaces.

Table 1. Allylsilylation of p-Chlorostyrene with Allyltrimethylsilane Using Various Acids

Ph +Ph

catalyst (0.10 g)SiMe3 SiMe31a 2a

3a

Catalyst

H+-Montmorillonite

Yield of 3a (%)

85Na+-Montmorillonite <1.0H+-USY 2.2H+-Beta <1.0H+-ZSM-5 <1.0

H+-Mordenite <1.0FSM-16 <1.0Amberlyst <1.0p-Toluenesulfonic acid a <1.0H2SO4

a <1.0

(1.0 mmol) (3.0 mmol)

n-heptane (1.0 mL)100 oC, 30 min

Catalyst Yield of 3a (%)

4-Cl-4-Cl-

a 0.1 mmol was used.

[1] I. N. Jung, B. R. Yoo, Synlett 1999, 519. [2] T. Shimada, K. Aoki, Y. Shinoda, T. Nakamura, N. Tokunaga, S. Inagaki, T. Hayashi, J. Am. Chem. Soc. 2003, 125, 4688.

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Transfer-Hydrogenation Catalyzed by (η5-pentaphenylcyclopentadienyl)RuCl(CO)2 – Mechanistic Insights

from Theoretical Modeling

Jonas Nyhlén, Timofei Privalov*, and Jan-E. Bäckvall*

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden [email protected], [email protected]

Two possible pathways of inner-sphere racemization of sec-alcohols using the (η5-pentaphenylcyclopentadienyl)RuCl(CO)2 catalyst (1) have been thoroughly investigated by means of density function calculations. To be able to racemize alcohols, catalyst 1 needs to have a free coordination site on the metal. This can be achieved either by an η5-η3 ring slippage or by dissociation of a carbon monoxide (CO) ligand. We found that the η5-η3 ring slip pathway has a surprisingly high potential energy barrier, 42 kcal/mol, which could be explained by steric congestion in the transition state and by the fact that ring slippage seems to be highly endothermic. We have computationally discovered an elegant mechanism which does not require η5-η3 ring slippage. The key features of this mechanism are CO-assisted alcohol exchange, generation of an active 16-electron complex via CO dissociation and β-hydride elimination as the racemization step. First, we have found unusual low energy pathway for reaction of 1 with potassium tert-butanol and two pathways for fast alkoxide-to-alcohol exchange with distinctive interaction between a leaving alcohol and one of the two CO ligands. We predict that dissociation of Ru-bound CO ligands does not occur in these reaction steps. Second, dissociation of one of two Ru-bound CO ligands has been found necessary only at some later stage of the reaction. The Gibbs free energy barrier for dissociation of a CO molecule was found to be 23 kcal/mol in toluene. Though this barrier is still quite high, our results indicate that the racemization process as such may proceed without crossing the CO dissociation barrier for each new alcohol. Thus, the dissociation of CO ligand is interpreted as a rate limiting reaction step in order to create a long-lived catalytically active 16-electron complex. Third, the key racemization step is portrayed. Finally, we report computed potential energy surfaces for CO dissociation from Ru center and reveal dependence of corresponding barriers on electronic properties of Ru-bound groups.

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Green Oxidation of Primary Alcohols to Aldehydes using Janibacter terrae DSM 13953 cells as Biocatalyst

T. Orbegozo,a J. G. de Vries,b W. Kroutila

a Department of Chemistry, University of Graz, Heinrichstr. 28, A-8010 Graz, Austria b DSM Pharmaceutical Products, Advanced Synthesis, Catalysis & Development, P.O. Box 16, 6160 MD

Geleen, The Netherlands

ox. cofactor red. cofactor

Janibacter terrae DSM 13953 cellsPi (100 mM, pH 7.5)

shaking, 30 °C

HR

OH

HR

O

acetaldehydeethanol

Conversions:94 %, R = Ph81 %, R = n-C7H1598 %, R = n-C5H11-CH=CH

Oxidation of alcohols to yield carbonyl compounds is one of the most fundamental and important processes in synthetic organic chemistry. In the search for alternatives driven by the immaturity of many organic oxidation reactions[1-3] and the necessity for “green” chemical processes,[4-7] several biocatalytic methods for alcohol oxidation have been developed and are being investigated with increasing intensity in order to tap the full potential of the excellent chemo-, regio-, and enantioselectivity of enzymes. Despite their unmatched advantage concerning environmental aspects, the requirement of cofactors and the availability of redox enzymes to tolerate high concentrations of organic (co)substrates sets limitations.

Nevertheless, a significant number of bio-oxidations of primary and secondary alcohols employing laccases[8,9] as well as novel redox enzymes have been developed[10-12].

We found that benzyl alcohol could be oxidised to benzaldehyde employing a wide range of biocatalysts. The bio-oxidation of primary alcohols to the corresponding aldehydes was most effective using Janibacter terrae DSM 13953 cells as biocatalyst.

Herein, the biooxidation of benzyl alcohols derivatives as well as alkyl alcohols, allyl and acetylenic alcohol derivatives was performed employing lyophilized cells of Janibacter terrae in a hydrogen transfer process using acetaldehyde as hydride acceptor, thus as formal oxidant.

Finally, new media were investigated for the oxidation of alcohols, thus mixtures of water/organic solvent for various miscible organic solvents (THF, DMSO, DMF, acetonitrile, dioxane, 2-propanol, 1-methyl-2-pyrolidone, t-butanol, acetone). Acknowledgements: This research was supported by a Marie Curie Research Training Network fellowship in the project "REVCAT" (MRTN-CT-2006-035866). [1] Königsmann, M.; Donati, N.; Stein, D.; Schönberg, H.; Harmer, J.; Sreekanth, A.; Grützmacher, H. Angew. Chem. Int. Ed. 2007, 46, 3567-3570. [2] Gheorghe, A.; Chinnusamy, T.; Cuevas-Yañez, E.; Hilgers, P.; Reiser, O. Org. Lett. 2008, 10, 4171-4174. [3] Su, F. Z.; Liu, Y. M.; Wang, L. C.; Cao, Y.; He, H. Y.; Fan, K. N. Angew. Chem. Int. Ed. 2008, 47, 334-337. [4] Sheldon, R. A.; Arends, I.; Hanefeld, U. In Catalytic oxidations in Green Chemistry and Catalysis, Wiley-VCH: Weinheim, 2007. [5] Thomas, C. M.; Letondor, C.; Humbert, N.; Ward, T. R. J. Organomet. Chem. 2005, 69, 4488-4491. [6] Bäckvall, J. E. (Ed.) In Modern Oxidation Methods, Wiley-VCH: Weinheim, 2004. [7] Mirafzal, G. A.; Lozeva, A. M. Tetrahedron Lett. 1998, 39, 7263-7266. [8] Potthast, A.; Rosenau, T.; Chen, C. L.; Gratzl, J. S. J. Mol. Catal. A: Chem. 1996, 108, 5-9. [9] Arends, I. W. C. E.; Li, Y. X.; Aunsan, R.; Sheldon, R. A. Tetrahedron 2006, 62, 6659-6665. [10] May, S. W.; Katopodis, A. G. Enz. Microb. Technol. 1986, 8, 17-21. [11] Cea, G.; Wilson, L.; Bolívar, J. M.; Markovits, A.; Illanes, A. Enz. Microb. Technol. 2009, 44, 135-138. [12] Kroutil, W.; Mang, H.; Edegger, K.; Faber, K. Adv. Synth. Catal. 2004, 346, 125-142.

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Interaction of bis(trimethylsilyl)Fe(II) Diiminopyridine Complexes with Aluminum Alkyls. A Well-Defined Model for the Study of the Fe-Diiminopyridine Olefin Polymerization Catalysts.

Pilar Palma, M. Ángeles Cartes, Juan Cámpora, Antonio Rodríguez-Delgado and Eleuterio Álvarez.

Instituto de Investigaciones Químicas, CSIC-Universidad de Sevilla. C/ Américo Vespucio, 49, 41092, Sevilla, Spain.

Iron transition metal complexes incorporating 2,6-bis(N-aryl)diiminopyridines (PDI) are highly active catalytic activities in ethylene polymerization and oligomerization. The low toxicity and cost of iron, and the possibility of readily tuning their catalytic properties by facile modification of the PDI ligands made them a very attractive alternative of well-known group 4 catalysts. However, since their simultaneous discovery by M. Brookhart and G. Gibson in 1998,1 the details of the reaction mechanisms associated Fe(PDI) catalysts have been the subject of controversy. Direct mechanistic investigation of these systems was difficult not only due to the paramagnetic nature of the iron(II) precursors, but by the lack of appropriate synthetic routes for the related organometallic alkyl derivatives. The organometallic chemistry of first-row transition elements with diiminopyridine ligands has revealed a surprising complexity, and attempts to synthesize the desired organometallic derivatives by conventional transmetallation reaction often afford unexpected products arising from reduction, deprotonation or C-C coupling reactions.

In our search for a convenient methodology for the development of suitable organometallic derivatives of alkyl derivatives of iron and other first-row transition elements stabilized by reactive imine-based ligands, we developed a methodology based in simple ligand exchange reactions involving reactive organometallic precursors of the type MR2L2, where L is a labile ligand, e. g., pyridine.2 This can be applied not only to diiminopyridine ligands, but also to other ligands, providing a very successful entry in the synthesis of corresponding (diiminopyridine)iron (II) alkyls. These complexes react in manner with aluminum alkyls cleanly affording formally Fe(I) complexes. These compounds catalyze the polymerization or oligomerization of ethylene (Scheme 1), providing a well defined system for the study of the mechanism of such reactions.

NFeN N

H2C CH2

R' R'

R' R'

SiMe3SiMe3

Al2Me6FeR2Py2

R = CH2SiMe3NFeN NR' R'

R' R'

N-N-NNFeN N

Me

R' R'

R' R'

" Fe(I)" Catalyst modelSiMe3

Al2Me6

Scheme 1 1) a) Small, B. L. et al. J. Am. Chem. Soc., 1998, 120, 4049. b) Bruce, M. et al. Chem. Commun. 1998, 2523. 2) a) Cámpora, J.; Conejo, M. M.; Mereiter, K.; Palma, P.; Pérez, C. M.; Reyes, M. L.; Ruiz, C. J. Organomet. Chem, 2003, 683, 220. b) Cámpora, J.; Naz, A. M.; Palma, P.; Álvarez, E. Organometallics, 2005, 24, 4878.

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The Role of Additives in Fischer-Tropsch Reactions

M. Perdjon-Abel, M. Tromp, J. Evans,

School of Chemistry, University of Southampton, Southampton, SO14 1BJ, United Kingdom

The Fischer-Tropsch Synthesis (FTS) is an alternative route to produce liquid fuels from a variety of carbon feedstocks including coal1 and biomass. Typically iron and cobalt based catalysts have been used for the FTS reaction, a reaction in which a mixture of CO and H2 (syn-gas) reacts to form hydrocarbons. Enhanced performance has been reported for iron based systems doped with alkali metals2 and chalcogenides3,4. Sulfides are considered a poison for most catalytic processes, but sulphur in the form of sulphates (SVI) is found to enhance the performance of iron based catalysts towards the FTS when present at low levels3,4.

For these reasons a structural study of a wide range of iron based catalysts has been carried out using characterisation methods such as X-ray Absorption Fine Structure (XAFS) spectroscopy, X-ray Photoelectron Spectroscopy (XPS), Powder X-ray Diffraction (PXRD) and Brunner-Emmett-Taller surface area determination (BET). The characterisation was performed before and after reduction of the catalysts (under H2) to form the catalytically active species.

Before reduction, PXRD identified a hematite iron oxide structure (Fe2O3) for all samples. The crystallinity of the iron oxide materials present, however, varied between samples. PXRD revealed changes in the iron oxide structure after reduction, the catalyst now mainly being composed of Fe and Fe3O4. The sulphur containing pre-reduced catalysts had sulphur present in the +6 oxidation state, as detected by XPS and XAFS. After reduction of these materials, some reduction of the sulphur oxidation state to +4 is observed, with traces of +2 and 0 present.

1. Dry, M.E. Catal. Today 2002, 71, 225 2. Herranz, T.; Rojas, S.; Perez-Alonso, F.; Ojeda, M.; Terreros, P.; Fierro, J. Appl. Catal. A Gen. 2006, 311, 66 3. Wu, B.; Bai, L.; Xiang, H.; Li, Y.-W.; Zhang, Z.; Zhong, B. Fuel 2004, 83, 205 4. Bromfield, T.C.; Coville, N.J. Appl. Surf. Sci. 1997, 119, 19

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Pyridine 2, 6-dicarboxylic acid as a catalyst for hydrophosphonylation of aldehydes and ketones

Golnaz Rasoli*, Mohammad A. Khalilzadeh

Department of Chemistry, Islamic Azad University of Chalus, Chalus,

The use of solid catalysts has received increasing attention in the past decades. Solid acid catalysts have afforded important advantages in organic synthesis, for instance, operational simplicity, nontoxic, reduced equipment corrosion, environmentally compatibility, reusability, low cost, and ease of isolation [1]. They have potential for safe and highly atom-efficient processes, and for simple workup procedures that do not produce vast amounts of salt wastes [2]. On the other hand, α-Hydroxy phosphonates and the corresponding phosphonic acids display a wide spectrum of biological activity [3]. α-Hydroxy phosphonic acid derivatives have been shown to be very important enzyme inhibitors. In this regard, we report here the synthesis of α-hydroxy phosphonates derivatives in the presence of a catalytic amount of pyridine 2,6-dicarboxylic acid (PDA) in aqueous media. The catalyst can either be recovered or after separation of the product the remaining aqueous layer can be used directly in the subsequent reactions. An efficient and simple synthesis of α-hydroxy phosphonates has been achieved via reaction of aldehydes and ketones with trimethylphosphite in the presence of catalytic amount of pyridine 2, 6-dicarboxylic acid in water. The method is simple, cost-effective and environmentally benign.

Refrences: [1] J.H. Clark, Acc. Chem. Res. 35 (2002) 791-797. [2] K. Kaneda, Synlett (2007) 999-1015. [3] D.V. Patel, K. Rielly-Gauvin, D.E. Ryono, Tetrahedron Lett. 31 (1990) 5591-5594.

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Rhodium Aqueous-Biphasic Hydroformylation of Allylbenzenes and Propenylbenzenes: study of the regioselectivity with

Rh-monophosphine and diphosphine systems.

Mariandry Rodrígueza, Eduardo A. Dutrab, Elena V. Gusevskayab and Eduardo N. dos Santosb*

aPostgrado en Química, Facultad de Ciencias, Universidad Central de Venezuela. Caracas, Venezuela. Email: [email protected]

b*Departamento de Química, ICEx, Universidade Federal de Minas Gerais, 31270-901 Belo Horizonte, Brazil

Rh-monophosphine and diphosphine systems were studied on the aqueous biphasic hydroformylation of some allylbenzenes and propenylbenzenes. Regioselectivity can be controlled varying the nature of the ligand [1]. The best operational parameters were determined using a Rh-monophosphine system (monophosphine tppts, P(C6H4SO3Na)3) and eugenol as the substrate, varying the temperature (60 to 120 ºC), the substrate/catalyst relation (2000:1 and 4000:1), the concentration of CTAB (0 to 0,01 M) and the ligand/catalyst relation (2.5:1 to 20:1). Hydroformylation of allylbenzenes and propenylbenzenes in the Rh-monophosphine system (monophosphine = tppms (C6H5)2P(C6H4SO3Na) and tppts), carried out using the best operational parameters (substrate : 10 mmol, water (20 mL), [Rh(cod)(μ-OMe)]2 : 0,25 x 10-3 mol, T: 100 °C, P: 20 atm (H2/CO = 1:1), stirred: 750 r.p.m.) gives lineal aldehydes close to 70 % selectivity and reactivity order was found: eugenol > estragole > safrole. However, the Rh-diphosphine system promotes the formation of branched aldehydes only if the auxiliary ligand have a bite angle near 90º (bdppets (tetrasulfonated 1,3-bis(diphenylphosphino)ethane),bdpppts(tetrasulfonated 1,3-bis(diphenylphosphino)propane))) and lineal aldehydes over 90 % when the bite angle is around 120º (bisbis (sulfonated 1,1′-bis(diphenylphosphino methyl)-2,2′-biphenyl). Chemoselectivity on the hydroformylation reaction of allylbenzenes and propenylbenzenes was excellent over 90 %.

T = 100 oC; P=20 atm (H2/CO = 1:1), Stirred: 750 r.p.m., Solvent: water (20 mL), Catalyst= [Rh(Ome)(COD)]2 (0,25x10-3 mol), Substrate= Eug l (20x10-3 mol). Ligand = 5 x 10-5 mol [CTAB] = 0.001 M

T = 100 oC; P =20 atm (H2/CO = 1:1), stirred: 750 r.p.m.,solvent: water (20 mL); Catalyst= [Rh(OMe)(COD)]2 (0,25x10-3 mol), Substrate = Eugenol (10x10-3 mol), Ligand = 2,5 x 10-5 mol; [CTAB] = 0.005 M. eno

[1] J. V. Barros, Humberto; Ospina, Maria L., Arguello, Eduardo, R. Rocha, William, V. Gusevskaya, Elena, dos Santos, Eduardo N. Journal of Organometallic Chemistry, 671, 2003, 150-15.

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Modified Mayenite Catalyst for High-Temperature N2O Abatement in Nitric Acid Plants

M. Ruszak1, S. Witkowski1, A. Kotarba1, Z. Sojka1, M. Inger2, M. Wilk2 1 Faculty of Chemistry, Jagiellonian University, ul. Ingardena 3, 30-060 Krakow, Poland

2 Instytut Nawozow Sztucznych, al. 1000-lecia Państwa Polskiego 13A, 24-110 Puławy, Poland

Mayenite (12CaO·7Al2O3) is a new catalytic material, proposed by us for high temperature decomposition of undesired nitrous oxide, present in process gases of nitric acid plants. The structure of this unique calcium aluminate is build of densely packed nanocages, creating positively charged framework, which is counter-balanced by extraframework anions, such as: O2-, O2

-, O-, O22-, OH- (Fig. 1). These anions can migrate

(doted arrow in Fig.1) through six-membered openings in the nanoporous network and take part in catalytic processes occuring at the mayenite surface [1]. Efective migration of guest anions starts above the Tamman temperature (ca. 800 K). They are proposed to be the key species in N2O decomposition process involved in the O-O bond formation step [2]. The mobility of the extra-framework oxygen species can be modified by substitution of Ca cations in Ca12Al14O33 by alkaline-earth ions of larger (Sr2+) and smaller (Mg2+) ionic radius. The results of TPSR tests (5% N2O/N2, GHSV = 7000 h-1) for pristine and

modified mayenite samples (Fig. 2) show that doping with strontium facilitates oxygen transfer to/from the mayenite surface lowering the temperature of N2O conversion, whereas smaller Mg2+ cations give rise consequently to an opposite behavior. Pilot-scale catalytic tests (850 ppm N2O, 8.15 % vol. NO, 2.5 % vol. NO2, 15 – 20 % vol. H2O, 4.5 - 4.8 % vol. O2; GHSV = 100 000 h-1) performed at 1150 K revealed that mayenite is an excellent high-temperature catalyst for deN2O under industrial conditions (Fig. 3). It is not only highly active and selective (in respect to NO and NO2) in nitrous oxide abatement, but also thermally stable. Moreover, it does not contain any transition metal ions, what is beneficial for safety reasons.

Fig. 1 Part of mayenite structure

(3 nanocages). Extra-framework anions are marked with spheres

Fig. 2 TPSR profiles for N2O decomposition test for mayenite

samples: undoped and modified with Sr and Mg, along with blank

experiment.

Fig. 3 Results of deN2O catalytic test, performed in

pilot plant at 1150 K with the use of real process gas feed.

"Project operated within the Foundation for Polish Science Ventures Programme co-financed by the EU

European Regional Development Fund" [1] M. Ruszak, S. Witkowski, Z. Sojka, Research on Chemical Intermediates, 33 (2007), 689-703 [2] M. Ruszak, M. Inger, S. Witkowski, M. Wilk, A. Kotarba, Z. Sojka, Catalysis. Letters., 126 (2008), 72-77

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A New Class of Functionalized Inorganic Monolithic Microreactors for Catalysis

Alexander Sachse, Abdelkrim El Kadib, François Fajula, Bernard Coq, Anne Galarneau

ICGM – UMR 5253 CNRS/UM2/ENSCM/UM1 ENSCM 8, rue de l’Ecole Normale 34296 Montpellier cedex 5 France

Continuous flow catalytic microreactors offer safe, eco-friendly and intensified processes for long-term production in fine chemical synthesis. The aim of our work is to investigate catalytic reactions in a flow-through process using functionalised Monolith reactors (MonoSil) as catalysts and showing their advantages over reactions performed in batch and packed-bed reactors. MonoSil consists of a concomitant macroporous (9 µm) and mesoporous (12 nm) network that allows a fast and controlled diffusion of reactants and products to and from the active sites within mesopores. The functionalisation of these materials is achieved by reacting the surface silanols with trialkoxy-organosilanes allowing the grafting of a wide variety of active organic functions (e.g. basic or acid) by a simple one-step recirculating flow process. In this way basic NH2-MonoSil and acid HSO3-MonoSil catalysts were elaborated. The behaviour of these catalysts was evaluated in two reactions: 1) the base-catalysed Knoevenagel reaction between benzaldehyde and cyanoethylacetate and 2) the acid-catalyzed transesterification of triacetine with methanol. The outcome of this work demonstrates that MonoSil catalysts in flow conditions are much more productive than the same catalyst used in batch and packed-bed reactors. HSO3-MonoSil showed to be 38 times more productive in monolith than in batch reactor, and 3 times more than in packed-bed microreactor. Furthermore no deactivation of the MonoSil catalyst for at least 28h was observed1. MonoSil reactors offer a great prospect in catalysis for fine chemical production.

1A. El Kadib, R. Chimenton, A. Sachse, F. Fajula, A. Galarneau, B. Coq, Angew. Chem. Int. Ed. in press

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Heterogeneous Rh-Catalyzed Reactions of Allylic Alcohols

Suman Sahoo,a Helena Lundberg, b Nanna Ahlsten, b Xiaodong Zou,*a Belén Martín-Matute*b a Department of Structural Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden b Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden

The development of metal-catalyzed reactions that are atom-economical, environmentally benign, and highly selective and that take place under mild reaction conditions is of extreme importance. The isomerization of allylic alcohols to the corresponding carbonyl compounds can be catalyzed by transition metal complexes. We have shown before that this transformation involves the formation of metal enolates. When this isomerization is performed under homogeneous conditions in the presence of an electrophile, a new C-C bond is formed in a regioselective manner.1 Here, we present our studies towards the use of immobilized transition metal complexes as heterogeneous catalysts in tandem transformations of allylic alcohols. Different strategies and supports for the immobilization have been compared in this study.

1. Bartoszewicz, A.; Livendahl, M.; Martín-Matute, B. Chem. Eur. J. 2008, 14, 10547-10550

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Metal Organic Frameworks (MOF) for Bridging the Gap between Homogeneous and Heterogeneous Catalysts

Avelino Corma*, X. Zhang, F. X. Llabres, M. Iglesias, F. Sánchez

Inst. Tecnología Química, CSIC-UPV. Avda de los Naranjos s/n, 46022 Valencia, Spain. Inst. Ciencia de Materiales de Madrid, CSIC. C/ Sor Juana Inés de la Cruz 3, Cantoblanco 28049 Madrid, Spain. Inst. Química

Orgánica, CSIC. C/ Juan de la Cierva 3, 28006 Madrid, Spain

Metal–organic frameworks (MOFs) are crystalline porous solids composed of a three-dimensional (3D) network of metal ions held in place by multidentate organic molecules. The spatial organization of these structural units leads to a system of channels and cavities in the nanometer length scale. Some applications of these porous materials for gas separation, gas storage or sensor, etc… have been described while catalytic application are scarcely published1. We have applied this class of porous metal organic framework into catalysis using two different approaches, i) applying the inherent catalytic properties of the inorganic cations and ii) the organic linkers of MOFs are used as ligands or support of the ligand to form transition metal catalysts. In the first case, and using the Cu cations in the MOF as active sites we have performed a cyclopropanation reaction with excellent activity and selectivities, being the catalyst fully recyclable (see table 1). Run Conversiona

(time)Selectivityb

cis/trans Selectivityb

cycloprop.1st 100 (2h) 18/76 94 2nd 95(2h) 20/75 95 3rd 98(2h) 17/77 96 a) Dichloromethane, room temp., 1% catalysts, low addition, b) GC-Mass

A preparative strategy consisting of covalent post-synthesis modification of an existing MOF with suitable functional groups. Thus, we have used this methodology for preparing a MOF containing a Au(III) Schiff base complex lining the pore walls, the resulting heterogeneous gold catalyst would emulate the catalytic properties of homogeneous counterparts (see scheme below). The modified MOFs containing gold are highly active, selective, and reusable catalysts for domino coupling and cyclization reactions in liquid phase, with yield above 90% and hydrogenation of 1,3-butadiene to 1-butene in gas phase with excellent selectivities (> 95%). It represents a novel catalyst that helps to bridge the gap between homogeneous and heterogeneous catalysis. In all cases, we have confirmed that the catalytic species are only into the solid and no metal leaching has been detected. 1 M. Eddaoudi, D.B. Moler, H. Li, B. Chen, T.M. Reineke, M. O’Keeffe, O.M. Yaghi, Acc. Chem. Res. 34 (2001) 319; G. Ferey, C. Mellot-Draznieks, C. Serre, F. Millange, J. Dutour, S. Surble, I. Margiolaki, Science, 309 (2005) 2040;

N2CHCOOEt

PhEtOOC

EtOOC

+

Ph

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Directed Evolution of Candida antarctica Lipase A Using an Episomaly Replicating Yeast Plasmid

Anders G. Sandström, Karin Engström, Jonas Nyhlén, Alex Kasrayan, Jan-E. Bäckvall

Department of Organic Chemistry, Stockholm University, Svante Arrhenius väg 12, SE-106 91, Sweden

We report a directed evolution of Candida antarctica lipase A, employing a combinatorial active-site saturation test (CAST) [1]. CalA has shown excellent activity towards large substrates, and has also displayed enantioselectivity towards tertiary alcohols. CalA has been used for the preparation of β-amino acids with excellent enantioselectivity. Furthermore; this lipase is highly thermostable and has intriguing sn-2 preference towards triglycerides [2].

Wild type CalA has a modest E-value of 5.1 in kinetic resolution of 4-nitrophenyl 2-methylheptanoate (1). Enzyme variants were expressed in Pichia pastoris by using the episomal vector pBGP1 which allowed efficient secretory expression of the lipase [3]. Iterative rounds of CASTing based on small libraries yielded variants with good selectivity toward both the (S)- and the (R)-enantiomer. The best obtained enzyme variants had E values of 52 (S) and 27 (R). The amino acid residue substitutions introduced in the (S)-selective variant have caused the acyl chain pocket to turn into a more spacious cavity (Fig 1.). The evolved enzymes and methodology will form starting points for further evolution of variants with selectivity towards substrates with other bulky moieties.

Fig. 1. Model displaying the active site of the (S)-1 selective CalA variant. The catalytic serine (Ser184), the catalytic triad participant His366 and the oxyanion hole stabilizer Asp95 is displayed. The preferred enantiomer (S)-1, bound to Ser184, is displayed in its tetrahedral intermediate form.

The new sets of amino acid residues are displayed in dark grey. [1] Reetz M.T., Carballeira, J.D. (2007) Nat. Protoc. 2: 891-903. [2] Dominguez de Maria, P., Carboni-Oerlemans, C., Tuin, B., Bargeman, G., van der Meer, A., van Gemert,

R. (2005) J. Mol. Catal. B: Enzym. 37: 36-46. [3] Lee ,C.C., Williams, T.G., Wong, D.W., Robertson, G.H. (2005) Plasmid 54: 80-85.

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Hydroformylation of olefins with cobalt catalyst in ionic liquids

Lucien Saussine,a* Lionel Magnaa and Hélène Olivier-Bourbigou a a IFP-Lyon, Rond Point de l’Echangeur de Solaize, BP3, 69360 Solaize

In the industrial hydroformylation of olefins other than propene, cobalt-based catalysts still dominate by far rhodium-based systems. The main reason is the low reactivity of rhodium for the branched olefins with internal carbon double bonds associated with the high boiling point of the aldehydes which would impose to much strain to the Rh catalyst during product separation by distillation. Despite these indisputable and unique benefits, the technology of cobalt-catalyzed processes has remained basically unchanged over the years. Nevertheless, some major issues still need to be addressed such as the cobalt recovery and recycle which are chemical consuming and generate waste.

We propose here a new strategy to recycle and recover the cobalt-catalyst without the addition of chemicals, by using ionic liquids and pyridine type ligands. The concept is based on the well-known existence of equilibria among neutral cobalt carbonyl species and charged carbonyl species in presence of pyridine. The latter charged species are trapped by ionic liquids, which allow their separation from organic reaction products, and their recycling. Drifting of these equilibria depends simply on the operating conditions (T, P). HCo(CO)4 can be simply regenerated from charged species, without adding any chemical product (see Scheme).

This concept has been successfully applied to the hydroformylation of isooctenes resulting from the dimerization of n-butenes by the Dimersol XTM process. We will discuss the results obtained and the influence of the parameters such as the effect of the ionic liquids and basic ligands in the process and we will propose a reaction and recycle mechanism on the basis of IR analysis. The recycling of the ionic liquid phase has been performed several times without loss of activity and selectivity1.

CO/H2

Olefins

[HCo(CO)4]Ionic Liquid

pyridineProductsP

T [Co(py)6]2+[Co(CO)4]2-

Recycle of the catalyst-ionic liquid phaseand regeneration of HCo(CO)4 under CO/H2 pressure Distillation column

Aldehydes

Recycle of non-converted olefins

IL phase

Heavy EndsP T

[PyH]+[Co(CO)4]-

1 Magna, L., Harry, S., Proriol, D., Saussine, L. and Olivier-Bourbigou, H., Oil and Gas Science and

Technology, 2007, 62 (6), 775-780.

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Copper(I) μ-Nitrene Bridged Complexes: Intermediates of Cu-Catalyzed Aziridination?

Fabian M Schneider, Hofmann, Peter*

Organisch-Chemisches Institut, Universität Heidelberg, INF 270, D-69120 Heidelberg, Germany [email protected]

Copper(I) nitrenes generally are assumed as reactive intermediates in copper-catalyzed aziridination reactions of olefins[1], although so far they have been neither isolated nor have they been detected spectroscopically.

Based upon previous work in our group, using a tailor-made anionic chelate ligand, which has led to the first in-situ characterization[2] and finally to the isolation of elusive copper(I) carbenes as key intermediates of Copper-catalyzed cyclopropanations[3], we have begun studies in search for analogous copper(I) nitrene complexes.

N3

NP

NCutBu

tBu

SiMe3

SiMe3

SCH3

CH3- SMe2

- N2N

PN

CutBu

tBu

Me3Si

SiMe3

NP

NCu

tButBu

Me3Si

SiMe3N

1 2

R

R

The novel and very labile, fully characterized copper(I)-thioether complex 1 serves as an ideal precursor, which reacts with various aryl nitrenes forming μ-nitrene bridged dinuclear copper(I) complexes 2, which have been characterized by spectroscopic methods and by X-ray crystallography.

The use of tosyl azide as a nitrene-source leads to a dicopper complex structually similar to intermediates of copper-catalyzed aziridination as postulated by Norrby et al.[4]

The structures of dicopper(I) μ-nitrene complexes will be discussed and their reactivity patterns will be presented. 1 a) Kwart, H.; Khan, A.A. J. Am. Chem. Soc. 1950, 89, 1951; b) Transition Metals for Organic Synthesis, 2nd Ed., edited by Beller M., Bolm C., 2004 WILEY-VCH, II/392. 2 Straub, B.F.; Hofmann, P. Angew. Chem. In. Ed. Engl. 2001, 40, 1288. 3 a) Shishkov, I. V.; Rominger, F.; Hofmann, P. Organometallics 2009, 28, 1049; b) Shishkov, I. V.; Rominger, F.; Hofmann, P. Inorg. Chem. 2008, 47, 11755. 4 P. Brandt, M.J. Södergren, P.G. Andersson, P.-O. Norrby J. Am. Chem. Soc. 2000, 122, 8013.

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Fast Optimization and Kinetic Measurements of Supported Ionic Liquid Phase (SILP) Catalysts in a Parallel Reactor Setup

Judith Scholz, Marco Haumann, Peter Wasserscheid

Lehrstuhl für Chemische Reaktionstechnik, Universität Erlangen-Nürnberg, Egerlandstr. 3, 91058 Erlangen, Germany

To combine the advantages of homogeneous and heterogeneous catalysis several approaches have been attempted using supported homogeneous catalysts or biphasic systems.[1] One very attractive concept called Supported Ionic Liquid Phase (SILP) combines these approaches by immobilizing the homogeneous catalyst in a thin film of an ionic liquid, adsorbed within the pores of a high surface area solid.[2] The negligible vapor pressure and the thermal stability of ionic liquids ensure that the solvent is retained on the support even at elevated temperature which makes SILP catalysts highly suitable for continuous processes.

Figure 1: Left: Single reactor line of the SILP catalyst screening rig with gas feeding section, control cabinet, reactor zone, multiport valve units and GC analysis. Right: Four out of 10 reactor lines. The performance of a SILP catalyst depends on numerous factors such as support material or ionic liquid.[3] With the plethora of supports and ionic liquids available, several hundreds of SILP catalysts are potential candidates. Thus, an efficient and reliable screening technique is mandatory.

Figure 1 illustrates a single reactor line of a gas-phase catalyst screening rig with ten parallel fixed bed micro reactors. The rig enables a fast and reliable screening of different SILP catalysts under steady state conditions. Beside the optimization of the SILP catalyst composition the determination of kinetic data can be achieved very efficiently. In this work we present latest results from gas-phase olefin metathesis reactions.

References: [1] a) D.J. Cole-Hamilton, Science, 2003, 233, 1702; b) M. Haumann, A. Riisager, Chem. Rev. 2008, 108, 1474. [2] A. Riisager, R. Fehrmann, S. Flicker, R. van Hal, M. Haumann, P. Wasserscheid, Angew. Chem. Int. Ed.

2005, 44, 185. [3] For recent advances please visit: www.silp-technology.de

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A Pincer-Type Anionic Platinum(0) Complex

Schwartsburd Leonida, Cohen Revitalb, Konstantinovski Leonidb and Milstein David*a

aDepartment of Organic Chemistry, bUnit of Chemical Research Support, Weizmann Institute of Science 76100 Rehovot, Israel

Pincer–type complexes constitute a large family of compounds that have attracted much recent interest. Among those, d8 pincer complexes of the type (LCL’)MII (M = Ni, Pd, Pt; L = charge neutral ligand, e.g. phosphine, amine, dialkyl sulfide) are a major group. They play important roles in organometallic reactions, mechanisms and catalysis.1 In contrast, we have prepared, characterized and computationally studied an unusual d10 (PCP)Pt0 anionic complex 2.2

F F

FFF

P(tBu)2

P(tBu)2

PtII

3P(tBu)2

P(tBu)2Pt0

Na+

1

C6F6

FastP(tBu)2

P(tBu)2PtII Cl

2

2Na

Oxidant

Reduction of the pincer-type PtII complex 1 results in the formation of the thermally stable anionic Pt0 complex 2. This complex adopts a T-shaped structure and exhibits diverse reactivity, including efficient electron-transfer processes, in which 2 is re-oxidized quantitatively to PtII, and C-F activation under mild conditions leading to formation of 3. Protonation of 2 with water gives a PtII hydride complex. 1 a) Albrecht, M.; van Koten, G. Angew. Chem., Int. Ed. 2001, 40, 3750; b) van der Boom, M. E.; D. Milstein, Chem. Rev. 2003, 103, 1759; c) Singleton, J. T. Tetrahedron 2003, 59, 1837; 2 Part of the results were communicated: Schwartsburd, L.; Cohen, R.; Konstantinovski, L.; Milstein, D. Angew. Chem. Int. Ed. 2008, 47, 3603.

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Catalytic borylation of allylic alcohols using palladium pincer-complexes

Nicklas Selander, Vilhelm J. Olsson and Kálmán J. Szabó

Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE- 106 91 Stockholm, Sweden, E-mail: [email protected]

Organoboronic acids play an important role in organic synthesis because of their use in various cross-coupling reactions.1 Consequently, there is a large interest to find mild and selective methods to synthesize these reagents from easily accessible starting materials.

We have found that palladium pincer complexes are excellent catalysts for the synthesis of organoboronates.2-4 For example, allylic alcohols can be converted to functionalized allylboronic acids under mild catalytic conditions. The allylboronic acid products can be isolated as potassium trifluoroborates or as various boronic acid esters. An alternative approach to avoid the often cumbersome purification of the allylboronic derivatives is to generate these species in situ. We have shown that the borylation of allylic alcohols can be efficiently combined with allylation of various electrophiles (e.g. aldehydes, ketones, acetals and imines) in a one-pot procedure.3,5,6 The products obtained from these reactions are stereodefined homoallylic alcohols, α-amino acids and amino alcohols. The high regio- and stereoselectivity of these reactions arises from the highly selective palladium-catalyzed formation of the transient allylboronates and the selective coupling of these species with the corresponding electrophile.

R OH R BOR

OR

Electrophile NHR´

COOH

R

OHR´

R´

R

OH

R

NHR´

(RO)2B B(OR)2

SePhPhSe PdCl cat

Isolation

R BF3K R Bpin

References: 1. Hall, D. G. Boronic Acids; Wiley: Weinheim, Germany, 2005. 2. Olsson, V. J.; Sebelius, S.; Selander, N.; Szabó, K. J. J. Am. Chem. Soc. 2006, 128, 4588. 3. Selander, N.; Kipke, A.; Sebelius, S.; Szabó, K. J. J. Am. Chem. Soc. 2007, 129, 13723. 4. Dutheuil, G.; Selander, N.; Szabó, K. J.; Aggarwal, V. K. Synthesis 2008, 2293. 5. Selander, N.; Szabó, K. J. Chem. Commun. 2008, 3420. 6. Selander, N.; Szabó, K. J. Adv. Synth. Catal. 2008, 350, 2045.

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Oxidant-Free dehydrogenation of alcohols and C-C cross-coupling of secondary and primary alcohols by Ag/Al2O3

Ken-ichi Shimizu, Kenji Suguno, Ryosuke Sato, and Atsushi Satsuma

Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Nagoya 464-860, Japan

Oxidation of alcohols to carbonyl compounds is important topics in catalysis. Recent efforts have been devoted to develop transition-metal-catalyzed oxidation of alcohols using environmentally friendly oxidants such as oxygen. From the viewpoint of atom efficiency and safety of the reaction, an oxidant-free catalytic dehydrogenation of alcohols is more ideal, and several examples using PGM catalysts have been reported. The construction of C-C bonds is a fundamental reaction in organic synthesis. Alcohols are not used as starting materials due to the poor leaving group ability of hydroxide. However, very recently there are a few reports of C-C bonds formation from alcohols based on the dehydrogenation-hydrogenation cycle of PGM catalysts. Here we present new and atom economical heterogeneous catalytic systems using Ag/Al2O3 for oxidant-free dehydrogenation of alcohols [1a] and one-pot C-C cross-coupling reaction of secondary and primary alcohols [1b].

Catalysts were prepared by impregnating oxides with an aqueous solution of silver nitrate followed by evaporation to dryness, calcination, and H2-reduction. When the reaction of 4-methylbenzyl alcohol was carried out in the presence of Ag/Al2O3 for 24 h, 4-methylbenzaldehyde was produced in 93% yield and 93% selectivity at alcohol conversion of 99%. H2 was generated nearly quantitatively. Because H2 escapes from the reaction mixture into the gas phase, the overall endothermic reaction is driven to the product side. The reaction was completely stopped by the removal of Ag/Al2O3 from the reaction mixture, which excludes a possible contribution of homogeneous catalysis of leached silver species. The filtered catalyst can be reused several times. Ag/Al2O3 showed higher activity than Ru/C, Ru/Al2O3, Pd/C and Pd/Al2O3. In the presence of catalytic amount of weak base (Cs2CO3), Ag/Al2O3 acts as a heterogeneous catalyst for one-pot C-C cross-coupling reaction of secondary and primary alcohols to give coupled ketones in good yields. This catalyst shows higher TON than PGM-Al2O3 catalysts. Mechanistic studies indicate that the reaction proceeds via the silver-catalyzed dehydrogenation of alcohols to give aldehyde, ketone and silver hydride intermediates, and the electrophilic aldehydes undergo the Cs2CO3-catalyzed aldol reaction with the ketone to the corresponding α,β-unsatutrated ketone, which finally is reduced by the silver hydride. Studies on the structure-activity relationship show that coordinatively unsaturated Ag sites as well as acid-base sites of Al2O3 are necessary for this reaction. Ag/Al2O3 act as an effective heterogeneous catalyst for the title reactions. These reactions are catalyzed by a cooperation of coordinatively unsaturated Ag site and acid-base sites on Al2O3 support. Fundamental information of this study allows chemists to design practical C-H activation catalysts without using PGM and organic ligands.

HO

R

OH

R'

O

R

O

R'

O

R R

O

R R

'

'

Ag

Ag-Hoxidation

aldol condensationby Cs2CO3

reduction

+ H2

[1] a) K. Shimizu, K. Sugino, A. Satsuma, Chem. Eur. J. 2009, 15, 2341; b) K. Shimizu, R. Sato, A. Satsuma, Angew. Chem. Int. Ed., 2009, 48, 3982..

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Aluminum Siting in Frameworks of Silicon Rich Zeolites. A Combined High Resolution 27Al 3Q MAS NMR and DFT/MM

investigation

Stepan Sklenak, Jiri Dedecek

J. Heyrovsky Institute of Physical Chemistry of the Academy of Sciences of the Czech Republic, v.v.i.

One of the most important properties of silicon rich zeolites is the presence of Al atoms in the framework and their siting in distinguishable framework T (T = Si, Al) sites. Since the protons, single metal ions and metal-oxo complexes, representing the active sites in catalytic and adsorption processes are bound to AlO4

- tetrahedra, the crystallographic positions of Al and the local aluminum distribution govern the location of the active sites and their properties. Therefore the knowledge of the Al siting is of crucial importance for both experimental and theoretical studies of catalysts based on silicon rich zeolites.

The siting of Al atoms in distinguishable framework T sites of silicon rich zeolites of the MFI,1,2 FER, CHA and TON3 structures was investigated employing 27Al 3Q NMR spectroscopy and DFT/MM calculations. It was found that the siting of Al atoms is neither random nor controlled by the thermodynamics of Al atoms in the distinguishable framework T sites. The calculations employing our newly developed bare charged framework model of a fully hydrated silicon rich zeolite allowed assigning observed 27Al NMR resonances to the corresponding distinguishable framework T sites for the studied structures. In addition, particular attention was paid to the presence of Al-O-(Si-O)1,2-Al. Our calculations revealed that the 27Al NMR isotropic chemical shift of Al in Al-O-(Si-O)1,2-Al in MFI can be significantly affected (up to 4 ppm) by the presence of the other Al.4 Thus the presence of Al-O-(Si-O)1,2-Al sequences in zeolites can result in a change of properties of AlO4

- tetrahedra.

References (1) Sklenak, S.; Dedecek, J.; Li, C. B.; Wichterlova, B.; Gabova, V.; Sierka, M.; Sauer, J. Angew. Chem., Int. Ed. 2007, 46, 7286. (2) Sklenak, S.; Dedecek, J.; Li, C. B.; Wichterlova, B.; Gabova, V.; Sierka, M.; Sauer, J. Phys. Chem. Chem. Phys. 2009, 11, 1237. (3) Sklenak, S.; Dedecek, J.; Li, C. B.; Gao, F.; Jansang, B.; Boekfa, B.; Wichterlova, B.; Sauer, J. Collect. Czech. Chem. Commun. 2008, 73, 909. (4) Dedecek, J.; Sklenak, S.; Chengbin, L.; Wichterlova, B.; Gabova, B.; Brus, J.; Sierka, M.; Sauer, J. J. Phys. Chem. C 2009, 113, 1447.

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Single Step, Metal templated synthesis of nanostructured soluble silsesquioxane catalyst supports

Andreas K. Skowron, Gijsbert Gerritsen, Hendrikus C. L. Abbenhuis and Dieter Vogt*

Eindhoven University of Technology, Homogeneous Catalysis and Coordination Chemistry, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

The need for rigid and nanosized scaffolds for the construction of molecularly defined catalysts is great. For instance, by grafting ligands or metal sites to dendrimers (scheme 1), molecular weight enlarged, homogeneous catalysts can be obtained. Interestingly, these can be retained by nanofiltration enabling continuous homogeneous catalysis. Dendritic supports, however, have several disadvantages that prompt development of new nanosupports. Here we report alternatives that, unlike dendrimers, do not result from repetitive synthesis steps, steric congestion in higher generations and high costs [1]. The synthesis of the novel, silsesquioxane based supports is simple and their size being between 2.5 and 4 nm (Scheme 1).

Scheme 1. New routes to affordable ~4 nanometer sized functionalized POSS supports.

Expanding the size of partially condensed silsesquioxane silanols (POSS) can be an alternative for dendritic supports. A typical POSS cage itself is already 1.5 nm and using a suitable coupling reaction could increase its size several times. Here we report the templation of metals to protect POSS silanol groups forcing the molecules to intermolecular reactions. After connecting POSS molecules with chlorosilane cross linkers the protecting metal can be conveniently removed through leaching with hydrogen peroxide.

Acknowledgement: This work is funded by the EU Nano-Host project.

[1] Halford, B. Chemical & Engineering News 2005, 83, 30-36; Hecht, S.; Fréchet, J. M. J. J. Am. Chem. Soc. 1999, 121, 4084-4085.

[2] Hanssen, R. W. J. M.; Van Santen, R. A.; Abbenhuis, H. C. L. Eur. J. Chem. 2004, 4, 678-683; Van der Vlugt, J.I.; Ackerstaff, J.; Dijkstra, T. W.; Mills, A. M.; Kooijman, H., Spek, A. L.; Meetsma, A.; Abbenhuis, H.C.L.; Vogt, D. Adv. Synth. Catal. 2004, 346(4), 399-412.

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Mechanistic considerations of diene metathesis catalyzed by heterogenized Grubbs-Hoveyda boomerang catalysts: Influence of the chelating ligand substituents in their activity and reciclability

Xavier Solans-Monfort,1,∗ Roser Pleixats1 and Mariona Sodupe1

Departament de Química, Universitat Autònoma de Barcelona, 08193-Bellaterra, Spain.

Immobilization of active organometallic complexes has been shown to be an excellent tool for stabilizing and recovering catalysts in many catalytic processes, such as olefin metathesis.1 Moreover, since the solid support is able to avoid in some cases several undesired reactions, the immobilization process can be a very useful strategy to get a deeper understanding of the catalytic process.2 In this way, the different reactivity of several silica immobilized boomerang diene metathesis catalysts with substituted N,N-diallyl-4-methylbenzenesulfonamides (Figure 1.)3 has been used as starting point for the understanding of the electronic role of benzene substituents in several Grubbs-Hoveyda type catalysts. Efforts have been focused both in determining the role of the

Hoveyda ligand substituents in the initial catalytic rates and also in determining their influence in the catalyst recyclability (catalyst leaching).

NSO2

NSO2 +

Ru

NN

ClCl

OR

X

R = CH2CH2CH2YCOYCH2CH2CH2SiO1.5-SiO2R'= H, CH3; X = H, NO2; Y = O, NH

Figure 1.

R'R'R' R'

Ru

NN

ClCl

O

X Ru

NN

ClCl CH2

Mes Mes

N

CH3

SO2

N

CH3

SO2

N

CH3

SO2

N

CH3

SO2

O

X

Figure 2.

InitiationMesMes

Propagationcycle

CatalystRegeneration

DFT calculations have confirmed that the nitro-substituted catalyst presents the weakest Ru···O interaction and thus favors the formation of the real active species (Figure 2). Nevertheless, it also presents the weaker Ru=C bond, which prevents the catalyst recyclability. Finally, calculations have been used to propose potential Hoveyda ligand modifications that may improve the catalytic activity.

References [1] Copéret, C.; Basset, J.-M. Adv. Synth. Catal. 349 78 (2007); Buchmeiser, M. R. Chem. Rev. 109 303 (2009). [2] Poater, A.; Solans-Monfort, X.; Clot, E.; Copéret, C.; Eisenstein, O. J. Am. Chem. Soc. 129 8207 (2007); Solans-Monfort, X.; Clot, E.; Copéret, C.; Eisenstein, O. J. Am. Chem. Soc. 127 14015 (2005). [3] Elias, X.; Pleixats, R.; Wong Chi Man, M. Tetrahedron 64 6770 (2008); Elias, X.; Pleixats, R.; Wong Chi Man M.; Moreau, J. J. E: Adv. Synth. Catal. 349 1701 (2007); Elias, X.; Pleixats, R.; Wong Chi Man M.; Moreau, J. J. E: Adv. Synth. Catal. 348 751 (2006).

∗ Xavier Solans-Monfort, Phone: +34 93 5868139, E-mail: [email protected]

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Nano Silica Copper Sulfate (NSCS) as a Highly Efficient, Novel Heterogeneous Catalysis for ‘Click Chemistry’ (Huisgen

Cycloaddition)

Mohammad Navid Soltani Rad, a* Somayeh Behrouz b and Mohammad Mahdi Doroodmand b a Department of Chemistry, Faculty of Basic Sciences, Shiraz University of Technology, Shiraz 71555-313, Iran

b Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71454, Iran

Huisgen 1,3-dipolar cycloaddition of azides and alkynes to afford 1,2,3-triazole rings has been widely used in industrial applications and synthetic intermediates. The high tolerance of other functionalities and the almost quantitative transformation under mild conditions make this reaction an ideal prototype to demonstrate the concept of ‘click chemistry’ developed by Sharpless and co-workers. However, the regioselectivity of this cycloaddition reaction is generally low and the reaction usually leads to a mixture of 1,4- and 1,5-regioisomers. K. B. Sharpless and M. Meldal showed that the rate of this coupling is dramatically accelerated under copper(I) catalysis, and that only one specific regioisomers of 1,4-disubstituted 1,2,3-triazole could be obtained. The required copper(I) catalysts are usually prepared by in situ reduction of copper(II) salts with ascorbate, or by comproportionation of copper(0) and copper(II). The catalysts might be copper(0) nanosize clusters, or appropriate copper(I) salts (CuI or CuBr) with triphenylphosphine, iminopyridine, or mono- or polydentate nitrogen ligands. However, the use of transition metals (copper powder, copper salts, or ruthenium salts) and ligands has led to the problem of waste disposal. The high costs of transition-metal catalysts coupled with the toxic effects associated with many transition metals have led to an increased interest in immobilizing catalysts onto a support. The classic supported reagents can facilitate both the isolation and recycling of the catalyst by filtration, thus providing environmentally cleaner processes. Hence, in this context, we have reported the novel nano-sized silica copper sulfate (NSCS) as a highly efficient heterogeneous catalysis for Huisgen 1, 3-dipolar cycloaddition. The synthesis of NSCS was achieved due to processes shown as a Scheme 1. The acid-base reaction of SSA with Cu(OH)2 provided the SCS which subsequently nano-sized under ultrasonic radiation. The NSCS has been used for synthesis the large number of potential chemotherapeutic agents (nucleosides, antifolates and so on) via Huisgen 1, 3-dipolar cycloaddition in many different solvents and reaction conditions (Scheme 1). The NSCS has been demonstrated to have favorable thermal and chemical tolerance and can be reused for many times without considerable reduction in reactivity.

Reference: Huisgen, R. In 1,3-Dipolar CycloadditionChemistry; Padwa, A., Ed.; Wiley: New York, 1984, 1–176

SiO2 OH + ClSO3H (neat) r.t. SiO2 OSO3H + HClSilica Sulfuric Acid (SSA)

SiO2 OSO3H2 + Cu(OH)2r.t.

SiO2 OSO32Cu + H2O2

Silica Copper Sulfate (SCS)

SiO2 OSO32Cu Nano-Silica Copper Sulfate (NSCS)

Ultrasound

Scheme 1.

R1 N N N + R2 NSCS (Cat.) ,Sodium AscorbateN NN

R1

Solvent, Condition

Solvent: H2O-THF, H2O-EtOH, PhMe,THF, MeCN, DMF...Condition:Room Temprature, Reflux, Microwave...R1, R2: Many Organic Moieties and Residues

Scheme 2.

R2

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Enantioselective hydrogenation of β-functionalized vinyl phosphonates

Sergio Vargas, María Ángeles Chávez, Andrés Suárez, Eleuterio Álvarez, Antonio Pizzano

Instituto de Investigaciones Químicas, Consejo Superior de Investigaciones Científicas-Universidad de Sevilla, Avda Américo Vespucio, 49; 41092, Seville (Spain)

Previously in our group, we have prepared a new family of phosphine-phosphite ligands, P-OP. Rhodium catalysts derived from P-OP ligands have provided good levels of activity and enantioselectivity in the hydrogenation of different olefinic substrates.[1] Aiming to extent the applications of P-OP ligands, we have studied the hydrogenation of β-acyloxi- and β-amido-vinyl phosphonates. The products resulting from the reduction of these new substrates are of interest due to their potential biological activity.[2,3] Initial results indicate that ligand 1 yields high enantioselectivities (up to 99% ee) in the asymmetric hydrogenation of several derivatives. In addition to catalytic experiments, some synthetic applications and preliminar mechanistic studies will be presented.

OO

But

But

PO

P

R R

P-OP(R = iPr, 1)

P(OMe)2O

Ar

X H2P(OMe)2O

Ar

X

[Rh(COD)(P-OP)]BF4

X = OBz, NHBz up to 99% ee

[1] M. Rubio, S. Vargas, A. Suárez, E. Álvarez, A. Pizzano Chem. Eur. J. 2007, 13, 1821 [2] R. Engel Chem. Rev. 1977, 77, 349 [3] F. Palacios, C. Alonso, J. M. de los Santos Chem. Rev. 2005, 105, 899

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A mesoporous chiral zeolite: ITQ-37

Junliang Sun1, Charlotte Bonneau1, Avelino Corma2, Daliang Zhang1, Mingrun Li1 & Xiaodong Zou1

1Structural Chemistry and Berzelii Centre EXSELENT on Porous Materials, Stockholm University, Sweden 2Instituto de Tecnología Química (UPV-CSIC), Spain

The synthesis of crystalline molecular sieves with pore dimensions that fill the gap between microporous and mesoporous materials is a matter of fundamental and industrial interest. The preparation of zeolitic materials with extra-large pores and chiral frameworks would open new perspectives for their applications. ITQ-37, a germanosilicate zeolite, is the first zeolite which fulfils all these requirements. Its structure was determined by combining selected area electron diffraction (SAED) and powder X-ray diffraction (PXRD) in a charge-flipping algorithm. The framework follows the srs minimal net and its extra-large 30-rings form two unique cavities where each cavity is connected to three other cavities to form a gyroidal channel system. These cavities describe the enantiomorphous srs net of the framework. ITQ-37 is the first chiral zeolite with one single gyroidal channel. It has the lowest framework density (10.3 T atoms per 1000 Å3) of existing 4-coordinated crystalline oxide frameworks, and the pore volume of the corresponding silica polymorph would be 0.38 cc.g-1.

ITQ-37 shows a good thermal stability. A pelletized sample calcined at 813K remained stable during two weeks when stored at room temperature in a moisture free environment. Acetalyzation of aldehydes of different molecular sizes with triethyl orthoformiate was performed using an Al containing ITQ-37 sample. Due to its big pore size, ITQ-37 shows better selectivity to acetal at high conversion with the bulkier aldehyde than zeolite Beta.

The framework and corresponding nets of ITQ-37. a, A slice (15.3 Å thick) viewed down the [111] direction. Only the T-T connections and the terminal hydroxyl groups are shown. All D4Rs have the same orientation. b, The 30-ring built from ten tertiary building units. One of them is highlighted. The centres of the tertiary building units fall on the nodes of one srs net (in orange). c, The large cavity defined by three 30-rings. The centres of the large cavities fall on the nodes of another srs net (in blue) that represents the gyroidal channel system.

Reference: 1. J. Sun, C. Bonneau, Á. Cartín, A. Corma, M.J. Díaz-Cabañas, M. Moliner, D. Zhang, M. Li, X. Zou “The ITQ-37 mesoporous chiral zeolite” Nature 2009, 458, 1154-1157

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Study on ρ-Alumina Supported Platinum and Palladium Catalysts - Physicochemical Characterization and Catalytic Reaction

Min Ho Sun a, Bit Na Joo a, Su Kyum Kimb, Kyun Ho Leeb, Myoung Jong Yub and Sung June Choa,*

aDepartment of Applied Chemical Engineering, Center for Functional Nano Materials (BK21), and the Research Institute for Catalysis, Chonnam National University, Gwangju 500-757, Korea

bSatellite Thermal and Propulsion Department, Korea Aerospace Research Institute, Taejon 305-333, Korea E-mail: [email protected]

Transition alumina, γ-, ρ-, η-, χ-Al2O3 etc is an important class of materials as a binder, adsorbent and catalyst. Recently, the transition alumina, ρ-Al2O3 has drawn much attention due to unique rehydration property that is beneficial for the washcoat or forming process, such as dense body, pellet or sphere. However, the preparation ρ-Al2O3 from Al(OH)3 is not straightforward because it needs heat treatment in vaccum or flash calcination within 1-10 sec. There is also a lack of information of ρ-Al2O3 including surface properties, thermal behavior, etc.

In this work, the Al(OH)3 with different particle sizes, 8-100 μm was used for the preparation of ρ-Al2O3 using flash calcination at 673-973 K. The obatined alumina was characterized with X-ray diffraction method, TGA, BET, scanning elecron microscophy and mercury porosimeter. The crystalline morphorlogy of the Al(OH)3 was retained upon the flash calcination, which was found to be typical ρ-Al2O3 referred from X-ray diffraction. The amount of water contained in ρ-Al2O3 can be controlled to 4-7% that was found to be critical for the binding ability when it was rehydrated. Also, the macroporosity larger than 10 nm in addition to micropore was developed to offer the route for facile diffusion of reactant and product without significant attrition or pressure drop.

Figure. scanning electron microscopy (SEM) of alumina granule.

References 1. P. Souza Santos. Materials Research, Vol. 3, No. 4, 104-114, 2000. 2. Xiaoyi Gong. Ind. Eng. Chem. Res. 2003, 42, 2163-2170. 3. Joseph B. Pullen, United states patent. 3,360,134

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A General and Efficient Copper Catalyst for the Double Carbonylation Reaction

Jianming Liu, Peiqing Zhao, Wei Sun*

State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, 730000, P. R. China

Email: [email protected]

The double carbonylation reaction can produce α-keto amides, esters and acids depending on the nucleophiles employed. These compounds are an important unit in several biologically important natural products or versatile intermediates for synthesis of α-hydroxy acids, α-amino acids and others. The traditional protocols for the double carbonylation reaction require the precious metal palladium as the catalyst.1 Air-sensitive phosphine ligands are usually required to promote the selectivity of double carbonylation. The use of phosphine ligands is a major problem associated with the double carbonylation reaction. Developing a novel catalytic system that is not dependent on phosphine ligands or precious metals to efficiently mediate this reaction is required.

N N

CuX

N NCl

N NCl

1: X = I; 2: X = Cl; 3: X = BrIPrCu-X L1 IPr HCl L2 IMes HCl

IR1

+ HNR2

R2 IPrCuI/IPr HCl NO

OR1

R2

R2

CO/Cs2CO3 NHCs have emerged as a class of ligands in metal-mediated reactions due to their strong

σ-donor properties compared with phosphine ligands, thereby enhancing thestability of NHC complexes toward heat and moisture.2 This characteristic property is suitable for maintaining efficient activity in the carbonylation because it is always carried out under rigorous conditions. On these grounds, [(NHC)CuX] (X=Cl, Br, I) complexes together with imidazolium salts were first subjected to the double carbonylation of aryl iodides with secondary amines. Under the optimal conditions, NHC-Cu-X based catalyst system show excellent activity in the double carbonylation reaction of aryl iodides and secondary amines.3 The new protocol requires a non-precious metal, and has greater generality than those previously reported. Reference: 1. (a) Abbayes, H.; Salaün, J. Dalton Trans. 2003, 1041. (b) Ozawa, F.; Soyama, H.; Yamamoto, T.;

Yamamoto, A. Tetrahedron Lett. 1982, 23, 3383. (c) Kobayashi, T.; Tanaka, M. J. Organomet. Chem. 1982, 233, C64.

2. Herrmann, W. A. Angew. Chem., Int. Ed. 2002, 41, 1290. 3. Liu J. M., Zhang R. Z., Wang S. F., Sun W., Xia C. G. Org. Lett. 2009, 11, 1321.

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Surface Organometallic Chemistry of Titanium on Silica-Alumina: Catalytic Hydrogenolysis of Waxes at Low

Temperature

Jean Thivolle-Cazat, Cherif Larabi, Nicolas Merle, Sébastien norsic, Mostafa Taoufik, Anne Baudouin, Kai Szeto, Aimery de Mallmann*, Jean-Marie Basset*

Laboratoire de Chimie Organométallique de Surface, UMR C2P2 CNRS-CPE-UCBL 5265 43 Bd du 11 Novembre 1918, 69616 VILLEURBANNE, Cédex, France. [email protected]

The low-temperature Fischer-Tropsch process produces rather pure and mainly long chain n-paraffins, up to C120. These long chains meet few economically interesting applications except as coating or lubricant. Conversely, diesel derived from the hydrocracking of F-T waxes with a cetane number of about 70 can be used to upgrade lower quality diesel.1 Usual hydrocracking processes are based on acidic catalysis at high temperature leading to deactivation by coke formation. Therefore, it appears interesting to develop new hydrocracking catalysts running at low temperature.

Surface Organometallic Chemistry (SOMC) is aimed at preparing well-defined supported organometallic species by grafting molecular complexes (Ti, Zr, Hf, Ta, Mo or Re ) on a support. 2 In this way, the tetra(neopentyl)titanium complex Ti(CH2CMe3)4 1 reacts with the OH groups of a silica-alumina (HA-S-HPV, Akzo-Nobel, 390 m2/g) treated at 500°C, forming mono- and bisgrafted species on the surface (≡SiO)Ti(CH2CMe3)3 2a and (≡SiO)2Ti(CH2CMe3)3 2b in a ratio close to 1/1. These surface complexes were fully characterised by spectroscopic methods, as well as elemental and mass balance analysis. Treatment under hydrogen at 150°C of 2a and 2b led to a mixture of supported Ti species. IRTF, ESR, 1H MAS, DQ solid-state NMR show the presence of ca 4% [(≡SiO)2TiH2], 3a, 81% [(≡SiO)2Ti(Me)-H], 3b and [(≡SiO)3Ti-H], 3c, 15% [(≡SiO)3TiIII], 3d, along with (SiHx) and (AlHx) fragments via the opening of adjacent Si-O-M bridges (M = Si, Al).

Species 3a-d efficiently catalyzes the hydrogenolysis of waxes (Figure 1) in a semi-continuous flow reactor at 180°C, 1bar H2 and prove more active and selective towards diesel than [TiH]/SiO2 and also more selective than [ZrH]/SiO2-Al2O3. The key catalytic step is likely a β-alkyl transfer.

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Figure 1: Hydrogenolysis of ASTM D87 wax catalyzed by [Ti-H]/SiO2-Al2O3 (200 mg, 1,82 wt% Ti; 400 mg wax; 180°C, H2: 1Bar, 20ml/min); weight distribution of a) wax; b) hydrogenolysis products; c) categorized hydrogenolysis products. [1] Leckel, D.; Liwanga-Ehumbu, M. Energy & Fuels 20, (2006), 2330-2336. [2] Lefebvre, F.; Thivolle-Cazat, J.; Dufaud, V.; Niccolai, G. P.; Basset, J.-M. Appl. Catal., A: 182, (1999), 1-8.

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Selective and Unexpected Transformations of 2-Methylpropane to 2,3-Dimethylbutane and 2-Methylpropene to 2,3-Dimethylbutene

Catalyzed by an Alumina-Supported Tungsten Hydride

Mostafa Taoufik*, Nicolas Merle, François Stoffelbach, Erwan Le Roux, Jean Thivolle-Cazat, Jean-Marie Basset*

Laboratoire de Chimie Organométallique de Surface, UMR C2P2 CNRS-CPE-UCBL 5265 43 Bd du 11 Novembre 1918, 69616 VILLEURBANNE, Cédex, France, [email protected]

The alumina supported tungsten hydride W(H)3/Al2O3, 3 was previously found to catalyse the alkane metathesis reaction which transforms any light alkane into its higher and lower homologues.1,2 For instance, propane was transformed into a mixture of ethane and butanes with smaller amounts of methane and pentanes.

The product selectivities in linear alkanes metathesis3 always follow the order Cn+1 > Cn+2 >> Cn+3 which are governed by steric interactions between substituents in [1,2] or [1,3]-positions of metallacyclobutanes.4 Surprisingly, in the case of 2-methylpropane, whereas (≡SiO)2TaH obeys the classical mechanism,4 complex 3 gives rise to the formation with a high selectivity, of an unexpected product: 2,3-dimethylbutane; in this case, the product selectivities ranges as follows: Cn+2 >> Cn+1 > Cn+3 (Figure 1). Then, this metathesis reaction of an iso-Cn paraffin leads to an iso-Cn+2 product instead of an iso-Cn+1, that is, involves formally the selective transfer of two carbons instead of one carbon as usually observed and depicted in the classical mechanism previously proposed for this reaction.4

Similarly, complexe 3 also transforms unexpectedly 2-methylpropene to 2,3-dimethyl- butenes (Figure 2) with a good selectivity which is the first example of productive metathesis of 2-methylpropene; again this highlights the role of 2-methylpropene as a primary product for the metathesis of 2-methylpropane. Therefore the following mechanism is proposed which shows the connection between the metathesis of 2-methylpropane and 2-methylpropene and explains the formation of all the products (scheme 1), given that alkanes arise from a subsequent hydrogenation of the liberated olefins.

5bMH

MH

7a

M H6b6aM H

7bMH

5aMH

M H

CH4

M

4

M H4

M3

3

(a) (b) (c)

M

Me

8b

M8a 5b

MH

5bMHMHMH

MH

7aMHMHMH

7a

M H6b M HM H6b6aM H 6aM HM H

7bMH

7bMHMH

5aMH

5aMHMHMH

M HM H

CH4

MMM

4

M H4 M HM H4

M3 MM3

3

(a) (b) (c)

M

Me

8bM

Me

8b

M8a

MM8a

Scheme 1: (a) and (c) classical and (b) unusual mechanistic pathways in the metathesis of 2-methylpropane and 2-methylpropene (M = W). References [1] Le Roux, E.; Taoufik, M.; Baudouin, A.; Coperet, C.; Thivolle-Cazat, J.; Basset, J. M.; Maunders, B. M.; Sunley, G. J. Adv. Synth. & Catal. 349, (2007), 231-237. [2] Le Roux, E.; Taoufik, M.; Coperet, C.; de Mallmann, A.; Thivolle-Cazat, J.; Basset, J. M.; Maunders, B. M.; Sunley, G. J. Ang. Chem. Int. Ed. Engl. 44, (2005), 6755-6758. [3] Vidal, V.; Theolier, A.; ThivolleCazat, J.; Basset, J. M. Science 276, (1997), 99-102. [4] Basset, J. M.; Coperet, C.; Lefort, L.; Maunders, B. M.; Maury, O.; Le Roux, E.; Saggio, G.; Soignier, S.; Soulivong, D.; Sunley, G. J.; Taoufik, M.; Thivolle-Cazat, J. J. Amer. Chem. Soc. 127, (2005), 8604-8605.

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Dynamic Kinetic Resolution of Primary Amines with Application to the Synthesis of NorSertraline

Lisa K. Thalén, Dongbo Zhao, Jean-Baptiste Sortais, Jens Paetzold, Christine Hoben, and Jan-E. Bäckvall*

Department of Organic Chemistry, Stockholm University, Arrhenius Laboratory SE-106 91, Stockholm, Sweden

An efficient process for the dynamic kinetic resolution of primary amines has been developed by our group via the combination of a ruthenium catalyst and a lipase, which provides the corresponding amides in high yields and high enantiomeric excess. The protocol was applicable with either isopropyl acetate or dibenzyl carbonate as the acyl donor. In the latter case release of the free amine from the carbamate products was carried out under very mild conditions. We have also developed a new route to NorSertraline, starting from readily available 1,2,3,4-tetrahydro-1-naphthylamine utilizing dynamic kinetic resolution as one of the key steps. The racemization of (S)-1-phenylethylamine with several different Ru-catalysts was evaluated and a racemization study of three different amines with varying electronic properties was also performed to determine the kinetic isotope effect.

4 mol% [Ru], CALBacyl group donor

HN

R1 R2

NH2

R1 R2

R3

O

toluene, 90 oCR1 = aryl, alkylR2 = alkyl

R3 = OBn or Meup to 95% isolated yieldup to > 99% ee

NH2

ClCl

HCl

NorSertraline

.

Thalén, L.K.; Zhao, D.; Sortais, J.-B.; Paetzold, J.; Hoben, C.; Bäckvall, J.-E., Chem. Eur. J. 2009, 15, 3403-3410.

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Enantioselective hydrogenation of β-Ketoesters in ionic liquid/supercritical CO2 biphasic system

Jens Theuerkauf; Giancarlo Franciò; Walter Leitner

[email protected] ; Institut für Technische und Makromolekulare Chemie, RWTH Aachen

Ionic liquids (ILs) and supercritical carbon dioxide (scCO2) emerged in recent years as a convenient solvent combination for carrying out continuous homogenous catalysed reactions under biphasic conditions.[1,2] While the polar IL-phase is highly suited for dissolving and immobilising the catalyst, scCO2 acts as the mobile phase for selectively extracting the products without any detectable IL cross-contamination. Moreover, in reactions involving gaseous reactants the presence of scCO2 results beneficial as it leads to a considerable enhancement of the gas availability in the catalyst phase and to an improved mass transfer.

The asymmetric ketone hydrogenation is an extremely useful transformation and a variety of catalysts have been developed for this purpose.[3] Within the cooperation project ChirAmAl, we are aiming to establish a continuous asymmetric hydrogenation of ketones with integrated product extraction by scCO2.

As first benchmark reaction, the hydrogenation of methyl-propionylacetate was carried out using a readily available Ruthenium-BINAP catalyst. A comparison between batch, semi-batch and continuous mode in IL/scCO2 system will be presented. Especially the influence of pressure and temperature on activity and enantioselectivity were investigated.

H3C OCH3

O OH3C

OH OH2

Ru - cat.

ionic liquid; CO2

CH3O

[1] M. F. Sellin, P. B. Webb, D. J. Cole-Hamilton, Chem. Commun. 2001, 781. [2] A. Boesmann, G. Franciò, E. Janssen, M. Solinas, W. Leitner, P. Wasserscheid, Angew. Chem. Int. Ed.

2001, 40, 697; M. Solinas, A. Pfaltz, P.G. Cozzi, W. Leitner J. Am. Chem. Soc. 2004, 126, 16142. [3] W. Tang, X. Zhang, Chem. Rev. 2003, 103, 3029.

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Colloidal gold for the aerobic oxidation of bulky alkenes

Kevin Guillois,1 Malika Boualleg,2 Laurence Burel,1 Jean-Marie Basset,2 Chloé Thieuleux,2 Valérie Caps1*

1 Institut de recherches sur la catalyse et l’environnement de Lyon (IRCELYON, CNRS / Université de Lyon), 2 avenue Albert Einstein, F-69626 Villeurbanne Cedex, France.

2 Laboratoire LCCPP (UMR 5265 CNRS-ESCPE-UCBL, équipe LCOMS), 43 Bd du 11 Novembre 1918, 69100 Villeurbanne, France

*[email protected]

Gold nanoparticles have been shown to catalyze a variety of oxidation reaction both in the gas and liquid phase.1 In gas phase oxidations (e.g. CO oxidation), their unique activity at low temperature critically relies on their association with a reducible oxide support (e.g. TiO2) which allows to trigger oxygen activation. In the aqueous phase, unsupported gold sols can readily oxidize glucose with molecular oxygen; however, the use of an activated carbon support allows preventing particle aggregation and hence deactivation of the catalyst.2 Recently, we have shown that supported nanoparticles could selectively oxidize trans-stilbene with molecular oxygen, using methylcyclohexane (MCH) as solvent.3 Here we present the synthesis and catalytic properties of gold sols in MCH. We show how the nature of the stabilizing agent influences activity and stability in the aerobic oxidation of bulky alkenes.

The gold sols were prepared using a classical biphasic system4 using a tretraalkyl ammonium compound as the phase transfer agent and octylsilane, octylthiol or ammonium as the stabilizing ligands. Elemental analysis and TEM allowed obtaining gold contents and gold particle size respectively. For catalytic evaluation, the alkene (substrate, 1 mmol) was dissolved in MCH (solvent, 20 mL / 155 mmol) and stirred (900 rpm) in air (1 atm) at 80°C, in the presence of tert-butyl hydroperoxide (TBHP, 0.05 mmol, i.e. 5mol%) and the gold sol (2 μmol Au). The reaction mixtures were analyzed by a Shimadzu GC-2014.

All gold sols exhibit significant activity for the aerobic epoxidation of stilbene (Figure 1). The epoxide yields achieved (40-90%) are higher than the value expected from direct reaction with TBHP (5%), indicating that unsupported gold can activate molecular oxygen from the air in the liquid phase. While the sol stabilized with ammonium ligands deactivates after a few hours, full conversion is reached over the octylsilane-stabilized gold sol. The results will be discussed in terms of gold particle size distributions and interaction between the gold particle and the stabilizing ligand.

0

20

40

60

80

100

0 20 40 60

Reaction time (h)

%

80

Figure 1: trans-stilbene conversion (squares) and epoxide yield (open circles) observed over Au@Si-R (red), Au@S-R (green) and Au@NH4

+-R (yellow)

References:

[1] C. Della Pina, E. Falletta, L. Prati, M. Rossi, Chem. Soc. Rev. 37 (2008) 2077-2095. [2] M. Comotti, C. Della Pina, R. Matarrese, M. Rossi, Angew. Chem. Int. Edit. 43 (2004) 5812-5815. [3] P. Lignier, F. Morfin, S. Mangematin, L. Massin, J.-L. Rousset, V. Caps, Chem. Commun. (2007) 186-188. [4] M. Brust, M. Walker,D. Bethell, D. J. Schiffrin, R. Whyman, Chem. Commun. (1994) 801-802.

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Synthesis of a new heterogeneous PROX catalyst through the controlled growth of inorganic nanostructures around

monodispersed Pt3Sn nanoparticles

M. Boualleg, J.-M. Basset, J-P. Candy, V. Caps*, J-C. Jumas, S. Norsic, L. Veyre, C. Thieuleux*

Laboratoire LCCPP– UMR 5265 CNRS-ESCPE-UCBL équipe LCOMS, ESCPE, 43 Bd du 11 Novembre 1918, 69100, Villeurbanne, France.

Université de Lyon, Institut de Chimie de Lyon, UMR 5256 CNRS (IRCELYON), 2 avenue Albert Einstein, 69626 Villeurbanne, France

Heterogeneous bi-metallic catalysts containing metal particles are currently prepared by decomposition of metal salts or complexes or by impregnation of metal particles onto oxide supports such as alumina or silica. These standard procedures are easy to handle but they can lead to a broad distribution of particles size and to a heterogeneous distribution of particles within the oxide framework. The aim of this work is to achieve a “one-pot” synthesis of a mesoporous silica around Pt3Sn nanoparticles. This new methodology should lead to the synthesis of new heterogeneous catalysts as mesostructured materials with a three-dimensional network of nanometric monodispered pores channels (dp varying from 2 to 10 nm) and containing Pt3Sn nanoparticles regularly distributed within the framework. To reach this goal, we have developed a two step synthetic methodology involving:

1) the direct synthesis at room temperature of a colloidal solution of the Pt3Sn alloy 2) the growth of a silica mesoporous structure around the Pt3Sn nanoparticles using the

sol-gel process via a templating routes. Using this new methodology, we have achieved the quantitative incorporation and the uniform distribution of 2 nm Pt3Sn particles along the pore channels of a silica matrix, as shown by extensive characterization of the as-synthesized Pt3Sn colloids and the nanoparticle-containing silica material (X-Ray Diffraction, Nitrogen adsorption/desorption, elemental analysis, T.E.M., EDX, Mössbauer …). This material turned out to be highly active at much lower temperature than a reference Pt/SiO2 catalyst in the preferential oxidation of CO (PROX: 2% CO / 2% O2 / 48% H2 in He, atmospheric pressure, 50 ml min-1, GHSV ~ 3000 h-1) (Figure). Light-off temperature is indeed decreased by 95°C. This stable Pt3Sn catalyst, which is thus active below 100°C, could be potentially applied in the promising proton exchange membrane fuel cell technology of the future hydrogen economy.

0

1

2

3

4

5

0 50 100 150 200 250 300Reaction temperature (°C)

r CO (m

mol

gP

t-1 s

-1)

Mass specific CO oxidation rates in the absence (empty symbols) and in the presence (full symbols) of hydrogen over the reference Pt/SiO2 (triangles) and our Pt3Sn/SiO2

(diamonds) catalyst

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Utilisation of CO2 via catalysis with ionic liquids

Richard H. Heyn, Terje Didriksen, Arne Karlsson, Knut Thorshaug, and Ørnulv B. Vistad

SINTEF Materials and Chemistry, Process Chemistry Departmen, P.O. Box 124 Blindern, 0314 Oslo, Norway

Carbon dioxide, CO2, is a viable and sustainable albeit not very reactive C1 feedstock. Two industrially relevant processes where replacement CO2 could have great impact on chemical sustainability are as substitutes for phosgene in the production of aromatic carbamates relevant to the polyurethane industry, and in the production of dimethylcarbonate (DMC).

ArNH2 + ROH + CO2 ArNHCOOR + H2O

CO2 + 2 MeOH MeOCOOMe + H2O

Improved CO2 reactivities have been observed when ionic liquids (ILs) are part of the reaction scheme. In particular, synthesis of diphenylurea (DPU), a potential precursor to aromatic carbamates, is reported to be produced in moderate yields in ILs,1 while the addition of ILs has been shown to improve the yield of DMC in some cases.2 In order to investigate the potential of ILs in these reactions, and to study a large variety of ILs systematically, we have initiated a high-throughput screening of a large parameter space of ILs and catalysts for the production of DMC and aromatic carbamates.

Batch scale reactions for the synthesis of DMC from MeOH, CO2, MeI, the IL [emim]Br and K2CO3 in general reproduced literature results.2 If the reaction is run under N2 instead of CO2, approximately the same yield of DMC is obtained, suggesting that CO3

2- is a viable source of a carbonyl group in these reactions. CO2 is however necessary for DMC production when KOH is used as a catalyst. Some dimethylether is detected as a gas phase product, consistent with the proposed mechanism for the formation of DMC from MeOH, CO2, and MeI.3

While no by-products are reported for DPU synthesis from aniline and CO2, in [bmim]Cl and with CsCO3 as catalyst,1 in our hands the yield is only 8.4 %, a third of that reported. In addition, significant amounts of secondary amine by-products are observed, as a result of nucleophilic attack of aniline on the Me and Bu groups of the [bmim]Cl IL. Addition of an alcohol to this reaction has not yet provided any carbamate. Interestingly, we have found a different system whereby a stoichiometric activator for the synthesis of DPU from CO2 and aniline becomes a catalyst upon addition of an IL. The effect of the IL on this reaction is still under investigation. Acknowledgements This work was only made possible through the generous support from the GASSMAKS program of Norwegian Research Council, Huntsman Polyurethanes and Sasol UK. References [1] Shi, F. et al. Angew. Chem. Int. Ed. 2003, 42, 3257. [2] (a) Wang, H. et al. Chin. Chem. Lett. 2005, 16, 1267. (b) Cai, Q.H. et al. Chin. J. Chem. 2004, 22, 422. [3] Fujita, S. et al. Green Chem. 2001, 3, 87.

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Synthesis of mononuclear Ru (II) complexes with phenanthroline-biscarboxylate ligand as water oxidation catalysts

Lianpeng Tong, Lele Duan, Yunhua Xu and Licheng Sun*

Department of Chemistry, School of Chemical Science and Engineering, Royal Institute of Technology (KTH), 10044 Stockholm, Sweden, Email: [email protected]

Due to the accessible higher oxidation states, ruthenium complexes are now regarded as the most promising water oxidation catalysts to mimic the oxygen-evolving complex (OEC) in Photosystem II (PSII) . During the past decades, a number of ruthenium-based catalysts have been prepared, but only a few of them are capable of oxidizing water to dioxygen in homogeneous system. Very recently, our group designed and synthesized a series of ruthenium complexes with biscarboxylate ligand, which exhibited high efficiency in catalytic water oxidation. Further research of these ruthenium complexes showed that the introduction of carboxylic groups promoted the water oxidation process. In order to increase the stability and efficiency of such ruthenium catalysts, we prepared a series of novel ruthenium complexes Ru(II)(ptda)(L)2 (ptda = 1,10-phenanthroline-2,9-dicarboxylic acid, L = pyridine 1; 4-methylpyridine 2; 4-bromopyridine 3) showed in figure 1. The catalytic properties of these ruthenium complexes towards water oxidation will be presented during the conference.

NN

OO

OORu

N

NN

OO

OORu

N

NN

OO

OORu

N

Br

Br

1 2 3 Figure 1. Molecular structures of Ru complexes 1-3 as catalysts for water oxidation.

References [1] Y. Xu, T. Åkermark, V. Gyollai, D. Zou, L. Eriksson, L. Duan, R. Zhang, B. Åkermark, L. Sun, Inorg.

Chem. 2009, 48, 2717-2719. [2] I. Romero, M. Rodríguez, C. Sens, J. Mola, M. Kollipara, L Francas, E Mas-Marza, A. Llobet, Inorg. Chem.

2009, 47, 1824-1834. [3] J. L. Cape, J. K. Hurst, J. Am. Chem. Soc. 2008, 130, 827 [4] L. Sun, B. Åkermark, S. Ott, Coord. Chem. Rev. 2005, 249, 1653-1663.

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Highly Efficient Route for Enantioselective Preparation of Chlorohydrins via

Dynamic Kinetic Resolution

Annika Träff , Krisztían Bogár, Madeleine Warner and Jan-Erling Bäckvall*

Department of Organic Chemistry, Arrheniuslaboratoriet, Stockholms Universitet, SE-106 91 Stockholm * Department of Organic Chemistry, Arrheniuslaboratoriet, Stockholms Universitet, SE-106 91 Stockholm

Entatiomerically pure chlorohydrins can be prepared via Dynamic Kinetic Resolution (DKR) by employing ruthenium catalyst 1 for in situ racemization and Pseudomonas cepacia lipase for kinetic resolution [1]. Optically active chlorohydrins are versatile intermediates and can be used as direct precursors in the synthesis of epoxides, β-aminoalcohols, pyrrolidines and functionalized cyclopropanes. Therefore this is an efficient route for the preparation of a variety of enantiomerically enriched compounds.

The DKR developed for this system is applicable on a variety of different β-chloro-aryl-alcohols with both electron-withdrawing and electron-donating groups. Conversions of up to 99% and ee up to >99 % were obtained. A few of the enantiomerically enriched chlorohydrins were transformed to the corresponding epoxides with high isolated yield. The ee was retained during the ring closure.

Scheme 1. Preparation of enantiomerically pure chloroacetates via dynamic kinetic resolution and further ring closure to the corresponding epoxides. References [1] Träff A., Bogár K., Warner M., Bäckvall J-E, Org. Lett., 2008, 10, 4807-4810

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FTIR spectroscopy in the studies of catalytic phenomena

Alexey A. Tsyganenko

V.A. Fock Institute of Physics, St. Petersburg State University, St.Petersburg, 198504 Russia, e-mail: [email protected]

The paper deals with the advances in FTIR spectroscopic studies of two phenomena, which should be common for homogeneous and heterogeneous catalysis. These are acidity and basicity induced by adsorption and linkage isomerism of surface species.

The strength of sites depends dramatically on surface coverage due to lateral interactions between adsorbed molecules1, whose mechanism includes surface relaxation induced by adsorption. Co-adsorption of weak acids with basic molecules demonstrates the effect of induced Bronsted acidity2, when in the presence of SO2, NO2, etc., protonation of such bases as NH3, pyridine or 2,5-dimethylpyridine (DMP) occurs on silanol groups that never manifest any Bronsted acidity. The effect suggests a new explanation of promotive action of some gases in the reactions catalyzed by Bronsted sites3. Induced basicity in the presence of adsorbed bases was detected4 by means of weak CH proton-donating molecules such as CHF3 or HCN as a test for the strength of surface electron-donating sites. Induced Lewis acidity was also established, and accounts for superacidic properties of sulfided oxides.

It is obviously adopted that a simple test molecule forms with a surface site only one complex with energetically most favorable geometry. Recently it was shown, however, that even diatomics such as CO reveal linkage isomerism and form with the cations or OH-groups, besides the usual C-bonded complex with the frequency shifted to higher wavenumbers, the energetically unfavorable O-bonded one with lowered frequency with respect to the gas phase5. The latter coexists in the thermodynamic equilibrium with the C-bonded form and has negligible concentrations at liquid nitrogen temperature. Having the energy considerably higher, this form of adsorption can be considered as some “sterically activated” state, which can play a role of intermediate in catalytic reactions6. Surface isomeric states were established for some other adsorbed species, such as cyanide ion CN- produced by HCN dissociation.

The existence of linkage isomerism can be explained by a simple electrostatic model, which takes into account the interaction of molecular quadrupole with the cations7. Besides linear configurations with positive sites, the model predicts side-on complexes of CO and N2 with surface anions, in agreement with a lot of experimental results8. Interaction of CO with the most basic oxygen sites of oxides leads finally to the formation of ‘carbonite’ CO2

2- ion, an ultimate case of side- on interaction with surface oxygen ion. Theory predict a correlation between the frequency shifts on adsorption and the integrated absorption coefficients. Recent data on CO adsorption on ionic surfaces are in a fair agreement with the theory9.

References: 1. A.A.Tsyganenko, L.A.Denisenko, S.M.Zverev, V.N.Filimonov. J.Catal., 94, 10-15 (1985). 2. A.A.Tsyganenko et al. Catal. Letters, 70, 159-163 (2000). 3. A.Travert et al. J. Phys. Chem. B, 106, 1350-1362 (2002). 4. Storozheva E.N., Sekushin V.N., Tsyganenko A.A. Catal. Letters. 107, 185-188 (2006). 5. C.Otero Areán et al. Intern. J.Mol.Sci., 3, 764-776 (2002). 6. A.A.Tsyganenko, P.Yu.Storozhev, C. Otero Areán. Kinet. Catalysis, 45, 530-540 (2004). 7. P.Yu.Storozhev et al. Appl. Surface Sci., 238, 390-394 (2004). 8. A.A.Tsyganenko et al. J. Mater. Chem., 16, 2358-2363 (2006). 9. E.V.Kondratieva, O.V.Manoilova, A.A.Tsyganenko. Kinet. Catalysis. 49, 451-456 (2008).

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FTIR study of the hydrogen cyanide photooxidation in HCN and HCN/H2O icy films at 77 K

Aida V. Rudakova, Ilya L. Marinov, Alexey A. Tsyganenko

V.A. Fock Institute of Physics, Department of Physics, St. Petersburg State University, Petergof, St.Petersburg, Russia 198504, e-mail: [email protected]

Hydrogen cyanide is one of the most toxic environmental pollutants. There are many natural and anthropogenic sources of this compound, which can be released into the atmosphere. Its removal from the environment is of a special significance.1 Industrial ways of cyanide destruction generally involve chemical treatment using various oxidation agents. Biological means of cyanide treatment have also been adopted using enzymes as detoxification agents.2 Here we report the FTIR spectroscopic results on the photooxidation of hydrogen cyanide in pure HCN and in mixed HCN/H2O icy films at 77 K. These condensed systems can be considered as a model for comparative investigation of the HCN oxidation process in different systems, such as aqueous solution, atmospheric gases, heterogeneous catalytic systems, biological systems, etc. Our results are useful for understanding the HCN oxidation processes taking place in homogeneous and heterogeneous systems like waste waters, soil, and atmospheric ice particles and aerosols.

The cell for spectral studies of adsorbed molecules at variable temperatures (55-370 K) was equipped with a device for vapour sputtering from the heated capillaries and deposition onto the inner BaF2 windows precooled by liquid nitrogen.3 Ozone was used as an oxidation agent. The systems under investigation were irradiated by a 120-W high-pressure mercury lamp DRK-120 (MELZ). The HCN/H2O ices with different component ratio were tested by low-temperature adsorption of CO.3

Irradiation of pure HCN film in the presence of ozone at 77 K leads to the formation of isocyanic acid HNCO as an intermediate product and CO2 and NOx as the final products. The products were identified on the basis of isotopic studies. The obtained spectral dependence of photo-ozonolysis of HCN at low temperature has shown that photoexcitation or photodissociation of ozone, evidently accounts for the observed processes.

In order to investigate the influence of the water addition upon the reaction mechanism, the photo-ozonolysis of hydrogen cyanide in mixed HCN/H2O ices with different water content at 77 K was carried out. It was found that water induces the dissociative ionization of HNCO and formation of the cyanate ion OCN−. The reaction rate increaces due to the formation of cyanic acid (HOCN). Therefore, water acts as a catalyst of the HNCOςHOCN isomerization process even at low temperature. Our results on the HCN oxidation in such condensed systems are compared with those for aqueous solution and biological systems.

References: 1. L. E. Towill et al., Reviews of the Environmental Effects of Pollutants. V. Cyanide. U. S. Environ. Prot.

Agen.pub. no. 600/1-78-027, Washington, D. C. (1978). 2. T. I. Mudder, J. L Whitlock, Miner. Metallurg. Proc., 161-165 (1984); C. S. Wang et al., Appl. Environ.

Microbiol., 62, 2195-2197 (1996). 3. A. V. Rudakova et al., Langmuir, 25 (3), 1482-1487 (2009).

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Development of Heterogeneous Ruthenium Catalysts Effective for the Addition of Aromatic C-H Bonds to Alkenes

Kenji Wada, Hiroki Miura, Saburo Hosokawa, Masashi Inoue

Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510 (Japan)

Directive carbon-carbon bond forming reactions via direct functionalization of C-H bonds by homogeneous transition metal complex catalysts, namely low-valent ruthenium complex catalysts, is of great importance because of their synthetic applications.1 On the other hand, heterogeneous catalysts, especially solid metal oxide-supported ones, are obviously advantageous from the practical and environmental viewpoints.2 Here, we are going to report the first example of the selective addition of aromatic ketones to alkenes via the activation of aromatic C-H bonds promoted by ceria- or zirconia-supported ruthenium oxide catalysts.

Supported Ru catalysts were prepared by the impregnation method. CeO2 or ZrO2 prepared by the treatment of cerium(III) nitrate or zirconium oxynitrate with aqueous ammonia was added to a solution of Ru3(CO)12 in THF under air at room temperature. After impregnation, powder was calcined at 400 oC for 30 min to afford Ru/CeO2 and Ru/ZrO2 catalyst. Catalytic reactions were performed in a glass Schlenk tube under an argon atmosphere by using a hot stirrer equipped with a cooling block for refluxing the solution. The products were identified by the use of GC-MS and NMR.

The Ru/CeO2 and Ru/ZrO2 catalysts did show excellent activity towards the addition of an aromatic C-H bond to vinylsilanes. For example, the addition of α-tetralone (1a, 1.0 mmol) to triethoxyvinylsilane (2a, 2.0 mmol) smoothly proceeded at 170 oC for 24 h in the presence of Ru/CeO2 or Ru/ZrO2 (0.025 mmol as Ru) together with triphenylphosphine (0.10 mmol) to afford the adduct 3a in 99% yield (eq. 1). The addition of a small amount of phosphine was indispensable. Remarkably, the reaction in the absence of the solvent smoothly proceeded to achieve high TON over 800. Various simple aromatic ketones and heterocyclic ketones were applicable to the reaction with triethoxyvinylsilane 2a to afford the desired products in moderate to high yields.

Note that silica-, alumina-, titania-, or magnesia-supported Ru catalysts prepared by the same method as Ru/CeO2 and Ru/ZrO2 did not give the desired adducts at all. The reaction of 1a and 2a was stopped by the hot filtration of bulk of the solid Ru/CeO2 catalyst after the reaction for 3 h, indicating that the reaction was operated on the surface of the solid catalyst. Effects of pretreatment of the catalysts will be also disclosed.

References: 1. S. Murai, F. Kakiuchi, S. Sekine, Y. Tanaka, A. Kamatani, M. Sonoda, and N. Chatani, Nature 366, 529 (1993). 2. P. T. Anastas and J. Warner, in Green Chemistry: Theory and Practice; Oxford University Press: New York (1998).

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Novel Hybrid, Tripodal and Tridentate Ligand Scaffolds for Homogeneous Catalysis

Jeroen Wassenaar, Ronald Lindner, Bart van den Bosch, Joost N.H. Reek, Jarl Ivar van der Vlugt*

*Laboratory for Homogeneous & Supramolecular Catalysis, van ‘t Hoff Institute for Molecular Sciences, University of Amsterdam, Nieuwe Achtergracht 166, 1018 WV Amsterdam, the Netherlands


The design of dedicated polydentate, privileged ligand architectures for the use in homogeneous catalysis is a continuous process of chemical creativity.1 Various methodologies will be presented in this poster presentation, aimed at underscoring some of the ongoing research in our laboratories in this area. We will detail results on the application of indole as a basic building block for the formation of chiral, hybrid phosphine-phosphoramidite scaffolds, which have found application in inter alia the asymmetric hydrogenation of Roche ester derivatives,2 sterically encumbered tripodal, tetradentate all-phosphorus entities3 or neutral tridentate pseudo-pincer frameworks. Details on the coordination chemistry and preliminary results concerning the reactivity of these species will be included.

Recent results on the chemistry and application of non-innocent pincer systems will be discussed, mainly with relation to the reactivity of first-row transition metal species.4 Furthermore, ongoing efforts to develop novel hybrid tridentate ligands and their metal complexes (Rh, Ir) will be enclosed, aiming for enhanced adaptability toward unactivated substrates.5

References 1 a) D. Morales-Morales, C.M. Jensen, The Chemistry of Pincer Compounds, 2007, Elsevier; b) J.I. van der Vlugt, J.N.H. Reek, submitted. 2 a) J. Wassenaar, S. van Zutphen, G. Mora, P. Le Floch, M. Siegler, A.L. Spek, J.N.H. Reek, Organometallics 2009, in press; b) J. Wassenaar, M. Kuil, J.N.H. Reek, Adv. Synth. Catal. 2008, 350, 1610-1614; c) J. Wassenaar, J.N.H. Reek, Dalton Trans. 2007, 3750-3753. 3 J. Wassenaar, M. Siegler, B. de Bruin, A.L. Spek, J.N.H. Reek, J.I. van der Vlugt, submitted. 4 a) J.I. van der Vlugt, E.A. Pidko, D. Vogt, M. Lutz, A.L. Spek, submitted; b) J.I. van der Vlugt, M. Lutz, E.A. Pidko, D. Vogt, A.L. Spek, Dalton Trans. 2009, 1016-1023; c) J.I. van der Vlugt, E.A. Pidko, D. Vogt, M. Lutz, A.L. Spek, A. Meetsma, Inorg. Chem. 2008, 47, 4442-4444. 5 R. Lindner, B. van den Bosch, J.N.H. Reek, J.I. van der Vlugt, in preparation.

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Kinetic study of methane steam reforming over Ni catalyst modified by silver designed by first principle

Hongmin Wang2, Anh H. Dam2, D. Wayne Blaylock1, Teppei Ogura1,Yian Zhu2, Anders Holmen2, William H. Green1*, and De Chen2**

1Massachusetts Institute of Technology, Cambridge, MA 02139 (USA) 2Norwegian University of Science and Technology, Trondheim, NO-7491 (Norway)

*[email protected] **[email protected]

Hydrogen production by steam reforming has been extended from methane to much more heavier feedstock such as natural gas, gasoline and diesel, as well as bioliquids in the past years. Nickel is the preferred SMR catalyst because of its cost and availability; however, it is susceptible to deactivation via carbon formation. Thus, the design of new SMR catalysts that are inexpensive but resistant to deactivation is of particular interest [1]. To aid in this search for improved catalysts, we seek an improved understanding of the processes occurring on the catalyst surface. DFT calculation indicate surface alloying such as Ag can increase the energy barrier of the surface reaction steps towards surface carbon formation, thus suppress also the filamentous carbon formation. In present work, a series of hydrotalcite-based Ni catalysts modified by different Ag loadings were prepared by surface redox reaction between the reduced Ni and AgNO3. The catalysts were characterized by many different techniques such as TPR, XRD, TEM and XPS. The effect of Ag surface alloying on the activity, kinetics and carbon formation of Ni catalysts was studied by using methane steam reforming as probe reaction. The relationships between Ag loadings and methane conversion, turnover frequency, activation energy, and coke formation were obtained, which will be discussed based on DFT calculation. It can be concluded that adding a small amount of Ag on the hydrotalcite-based Ni catalyst can strongly suppress the carbon formation, while turnover frequency is deceased and the activation energy is increased. The results of this study are helpful for the design of a high performance catalyst for methane steam reforming. Table 1 Catalyst used in this work

Catalyst Area percentage of Ag on the surface of Ni crystal Ni 0 5Ag95Ni 5% 25Ag75Ni 25%

References 1. Rostrup-Nielsen, J.R., J. Sehested, and J.K. Nskov, Advances in Catalysis. 2002, Academic Press. p. 65-

139.

0

1

2

3

4

5

6

7

500 525 550 575

Reaction temperature(oC)

TOF(

1/s)

Ni5Ag95Ni25Ag75Ni

Fig.1 Effect of Ag loading on turnover frequency under the condition of molar steamto methane ratio of 3.5 and molar CH4 to H2 ratio of 1.0

Fig.2 Effect of Ag loading on carbon formation for methane steamreforming at 700oC and molar steam to methane ratio of 0.5

0

0.2

0.4

0.6

0.8

1

0 5 10 15 20 25Ag loading (%)

Car

bon

form

atio

n ra

te(m

gcar

bon/

(h.m

gcat

))

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Unexpected Formation of a Cyclopentadienylruthenium Alkoxycarbonyl Complex with a Coordinated C=C Bond

Jenny Åberg, Madeleine Warner, Jan-Erling Bäckvall*

Department of Organic chemistry, Arrheniuslaboratory, Stockholms Universitet, SE-106 91 Stockholm,

Email: [email protected]

Ruthenium catalyst 1 has successfully been used as an efficient racemization catalyst for secondary alcohols at room temperature. The combination of catalyst 1 with an enzyme and an acyl donor can be used to transform racemic alcohols to enantiomerically pure (R)-acetates in high yields and with excellent ee values via dynamic kinetic resolution (DKR) [1]. However, in connection with research on 1,4-diols, it was found that the racemization of 5-hydroxy-1-hexene is considerably slowed down and therefore DKR of this unsaturated alcohol has not yet been successful. Inhibition of the racemization could be due to coordination of the double bond to ruthenium. The reaction of (η5-Ph5Cp)Ru(CO)2(Ot-Bu) 2 and 5-hydroxy-1-hexene has therefore been thoroughly studied by NMR spectroscopy and in situ IR spectroscopy (Scheme 1). These experiments have provided evidence for the formation of two diastereomers of an alkoxycarbonyl complex in which the terminal double bond is coordinated to ruthenium (3a-b, Scheme 1). 1H NMR and 13C NMR show shifts upfield for the double bond protons which is in accordance with literature values upon coordination to ruthenium [2, 3]. The carbonyl peaks of the complexes appear at δ 203.50, 203.56 and 204.0 ppm, in a ratio of 1 : 1 : 2. IR peaks were detected at 1982 (CO) and 1644 (acyl) cm-1.

Scheme 1: Formation of diastereomeric complexes 3a-b. References [1] Martín-Matute, B.; Edin, M.; Bogár, K.; Bäckvall, J.-E. Angew. Chem. Int. Ed. 2004, 43, 6535-6539. [2] McWilliams, K. M.; Angelici, R. J. Organometallics 2007, 26, 5111-5118. [3] Alvarez, P.; Lastra, E.; Gimeno, J.; Brana, P.; Sordo, J. A.; Gomez, J.; Falvello, L. R.; Bassetti, M. Organometallics 2004, 23, 2956-2966.

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Continuous Gas Phase Asymmetric Hydrogenation using Novel Supported Ionic Liquid Phase (SILP) Catalysts

E. Öchsner, M. Haumann, P. Wasserscheid

Chair of Chemical Reaction Engineering, University Erlangen-Nuremberg, Egerlandstr. 3, D-91058 Erlangen, Germany, [email protected]

Supported Ionic Liquid Phase (SILP) catalysts are novel materials consisting of an ionic liquid, metal catalyst and a porous support.[1] The support is covered with a thin film of ionic liquid and the homogeneous or heterogeneous catalyst is dissolved in this ionic liquid film. The ionic liquid stabilizes the homogeneous catalyst and enables easy product separation and catalyst recycling. Therefore the SILP-catalysis concept combines the advantages of homogeneous and heterogeneous catalysis.

In recent years SILP catalyst systems have been successfully applied in gas phase and liquid phase reactions.[2] The use of SILP-systems in gas phase reactions is up to now only realized for reactions with simple selectivity properties (e.g. hydroformylation, methanol carbonylation and hydrogenation).

In order to expand the field of SILP - applications in gas phase on reactions with complex selectivity behaviour this contribution presents a successful experimental concept from liquid systems to gas phase reaction[3,4] and reports the first successful SILP-catalyzed asymmetric hydrogenation in the gas phase.[5] The studies focus on the asymmetric hydrogenation of a β-keto ester to a β-hydroxy ester - structive motif for a number of important active agents.

For the first time a SILP catalyst was designed and successfully applied for the asymmetric hydrogenation in a continuous gas phase process with high activities and enantioselectivities. The reaction in gas phase offers a solvent-free experimental concept and the easy immobilisation and recycling of expensive homogeneous chiral catalyst complexes. This study may help to improve reaction systems and to design green processes for the pharmaceutical, the nutrition and the fine chemical industries.

_______________________________________________

[1] C. P. Mehnert, R. A. Cook, N. C. Dispenziere, M. Afeworki, J. Am. Chem. Soc. 2002, 124, 12932-12933. [2] Y. Gu, G. Li, Adv. Synth. Catal. 2009, 351, 817 - 847. [3] E. Oechsner, B. Etzold, K. Junge, M. Beller, P. Wasserscheid, Adv. Synth. Catal. 2009, 351, 235 – 245. [4] E. Oechsner, K. Schneiders, K. Junge, M. Beller, P. Wasserscheid, Applied Catalysis A: General, submitted. [5] E. Oechsner, M. Haumann, P. Wasserscheid, patent, in registration.

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Amino-acids in Clays – towards environmental applications

Pedro D. Vaz, Cristina I. Fernandes, Nuno U. Silva and Carla D. Nunes

CQB, Department of Chemistry and Biochemistry, Faculty of Science, University of Lisbon, Campo Grande, Ed. C8, 1749-016 Lisbon, Portugal

Layered double hydroxides, available as minerals or from synthesis, and known as anionic clays, are very versatile. Hydrotalcite (HTC) is an anionic clay from this family, based on Mg and Al cations, but a wide range of compositions with general formula (M2+ = Mg2+, Zn2+, Ni2+ etc., M3+ = Al3+, Cr3+, Ga3+ etc) is possible.[1] A rich intercalation chemistry can be obtained not only from the anion exchange process, but also from substitution of the di–and trivalent cations in the layers. In the present work two enantiopure amino-acids, tryptophan (trpH) and phenylalanine (pheH) were intercalated inside the interlayer spacing of the clay by the reconstruction method. Subsequent introduction of an Mo-based organometallic core was accomplished by using the precursor complex [MoI2(CO)3(NCMe)2]. For comparison purposes the equivalent homogeneous phase complexes were also prepared yielding complexes formulated as [MoI2(CO)3(L^L)] (L^L = trpH or pheH). Both the composite materials and the complexes were afterwards characterized by FTIR, powder XRD, among other techniques to confirm the successful intercalation of the hosts. All the Mo containing species were then tested in the enantiosselective catalytic epoxidation of olefins both in homogeneous (complexes) and heterogeneous (clays) phases. This is an important reaction as epoxides are relevant starting materials in industrial applications.

Scheme 1. Synthetic procedure for preparation of organometallic hybrid clays.

Results show that conversions range between 70 through 90% for cy8 and 60 through 85% for sty. Further results will be discussed in terms of yields, kinetics and enantiosselectivity. Comparison with similar catalytic systems, based on pyridine ligands, show that the conversions are somewhat similar for the same [MoI2(CO)3] core. An in-depth and more detailed comparison is to be presented at the meeting. Acknowledgements The authors are grateful to PIDDAC and FCT for financial support (PTDC/QUI/71576/2006). References [1] Newman, S.P., Williams, S.J., Coveney, P.V., Jones, W., J. Phys. Chem. B, 102 (1998), 6710-6719.

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Silica-Supported Bis-N-Heterocyclic Carbene Complexes of Palladium and their Application in Cross-Coupling Reactions

Elizabeth Tyrrell*, Leon Whiteman and Neil Williams*

Kingston University, School of Pharmacy & Chemistry, Surrey, UK * [email protected], [email protected]

N-Heterocyclic carbenes (NHCs) are rapidly becoming a versatile and efficient alternative to traditional phosphine-based ligands in organometallic chemistry1. The steric properties of the N-substituents have been reported to have a significant effect on the activity of the metal-NHC catalyst, with bulky substituents usually increasing activity2. Although numerous examples of immobilised NHC complexes can be found in the literature, most seem to employ sterically undemanding alkyl-substituted NHCs3.

A range of NHC complexes of palladium have been immobilised on silica and their application in cross-coupling reactions has been investigated. N-substituted imidazoles (N-methyl, N-benzyl, N-mesityl and N-(diisopropyl)phenyl) were reacted with 3-(bromopropyl)trimethoxysilane to produce imidazolium salts (1). Deprotonation with Ag2O generates silver NHC which were used as transfer agents with Pd(PhCN)2Cl2 to yield bis-(NHC) palladium dichloride complexes (2). These could be tethered to silica gel yielding the precatalysts (3) (figure 1). The palladium complexes were characterised by high-resolution mass spectrometry and 1H and 13C NMR. NMR analysis indicated the presence of rotameric isomers4. Preparing the precatalyst prior to immobilisation was thought to be the best route to create well defined silica supported catalysts.

N+

N

Si(OMe)3

N

NPd

N

NCl

Cl

(MeO)3Si

Si(OMe)3

Br-

N

NPd

N

N Cl

Cl

1) Ag2O

2) Pd(PhCN)2Cl2

SiO2

(1) (2)

(3)

The resulting silica-supported bis-NHC Pd complexes are stable to air and moisture and have been prepared using a relatively 'green' process. These catalysts show good activity in Suzuki reactions of aryl iodides and bromides (>99% conversion using our conditions), however only modest conversions (<50%) were obtained for couplings employing aryl chlorides. The catalysts also show moderate activity in Sonogashira and Heck cross coupling reactions and have the potential for recyclability. Notably the catalysts bearing NHCs with bulky N-mesityl and N-(diisopropyl)phenyl substituents as ligands show superior activity in all reactions.

___________________________________________ 1 Fremont, P.; Marion, N; Nolan, S. Coord. Chem. Rev. (2009) 862-892. 2 Kantchev, E.; O’Brien, C.; Organ, M. Agnew. Chem. Int. Ed. (2007) 2768-2813. 3 Sommer, J.; Weck, M. Coord. Chem. Rev. 251 (2007), 860-873. 4 Vin Huynh, H.; Wu, J. J. Organomet. Chem. (2009) 323-331.

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Electrospun Heterogeneous Noyori Catalysts, Study on Structure Design, Preparation and Investigation

Da-Yong Wu*, Jian-Hua Cao and Hai-Yan Wang

Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, 100190 Beijing, China

Although showing obvious advantages over homogeneous catalyst, heterogeneous catalyst still retains some considerable problems. Aiming at the unsolved issues of heterogeneous catalyst, including low activity, irregular shapes, small pore size, low surface area, the low mobility of active centers and the difficulty to access to the inner space of immobilized catalysts, this study has probed into the strategy to construct the ideal heterogeneous catalysts by employing Electrospinning method.

A developed Electrospinning method is able to prepare materials possessing improved properties, nano-sized, high porosity, high surface area, uniform shapes, and controllable fiber/particle diameters (Figure. 1 and 2). It is considered hopeful to achieve better dispersion, accessibility and activity of the heterogeneous catalysts.

The designed silyl-functionalized noyori catalysts were electrospun in the presence of the co-condensation agent MeSi(OMe)3. The prepared nano-fiber and nano-particle matrix with active centers formed heterogeneous catalysts (Scheme 1). The catalyst test, hydrogenation of α,β-unsaturated ketone (Scheme 2) revealed that the catalytic activity of nano fiber/ particle-supported catalysts was remarkably increased, compared with those heterogeneous catalysts which were synthesized by the routine Sol-Gel process.

The relationship between the structures (the shape of supporting matrix, loading and dispersion of the active centers) and the consequential catalytic performances of hetero-geneous catalysts, and the effective way to construct better heterogeneous catalysts via the Electrospinning method were also discussed.

Figure 1. Particle-supported catalyst. Figure2. Fiber-supported catalyst

Si(OCH3)3

RuP

P

N

N

Cl

Cl

Ph2

Ph2

+ MeSi(OMe)3/Polymer Fiber/Particle-Supported Heterogeneous Catalysts

Electrospinning

O OH O OHH2

Cat. + +

Scheme 1. The preparation of fiber/particle supported catalysts. Scheme 2. The hydrogenation of α,β-Unsaturated ketone

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Efficient, recyclable palladium catalyst immobilized on cross-linked polymer-supported ionic liquid: Application in the

carbonylative-Sonogashira coupling reaction

Yan Wang, Jianhua Liu*, Chungu Xia*

State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences and Graduate School of the Chinese Academy of Sciences,

Lanzhou 730000, P. R. China, Email address: [email protected]; [email protected]

α,β-Alkynyl ketones appear in many biologically active molecules and play crucial roles as intermediates in the synthesis of natural products and druglike molecules. Traditionally, α,β-alkynyl ketones are generally synthesized via the coupling of alkynyl organometallic reagents with acid chlorides[1], traditional methods have employed Pd- and (or) Cu-catalyzed coupling reactions of acid halides and terminal alkynes. However, these methods have to be handled in dry solvents under an inert atmosphere. An alternative synthesis method for α,β-alkynyl ketones is the transition metal-catalyzed coupling of organic halides with terminal alkynes in the presence of carbon monoxide[2], however, Pd-phosphine complexes are often used in the carbonylative sonogashira coupling reaction under homogeneous conditions. As a part of our ongoing efforts to develop efficient heterogeneous catalytic systems for the important reaction[3,4]. In this work, we had preapred a highly cross-linked polymer-supported ionic liquid (PSIL) by copolymerization of 3-butyl-1-vinylimidazolium iodide ([VBIM]I) with the cross-linker divinylbenzene (DVB). Using PSIL as support, a novel immobilization of Pd(OAc)2 on PSIL (Pd/PSIL) catalyst has readily formed and the average particle diameter was found to be about 20 nm (Fig. 1 and 2). The heterogeneous cross-linked polymer supported Pd was demonstrated to be an efficient catalyst for the carbonylative-Sonogashira coupling reaction of aryl iodides with terminal alkynes under phosphine-free condotions (Scheme 1), giving the corresponding α,β-alkynyl ketones in good to excellent yields (48%-98%). Moreover, the immobilized heterogenous catalysts can be recycled 5 times with no significant loss of the catalytic activity in the carbonylative-Sonogashira coupling reaction of iodobenzene with phenylacetylene (run1: yield 90%, run2: yield 90 %, run3: yield 87%, run4: yield 85%, run5: yield 84%).

Fresh catalyst fifth reused catalyst Fig 1. Cross-linked polymer supported Pd Fig. 2 TEM of Pd/PSIL

References [1] C. Chowdhury, N.G. Kundu, Tetrahedron, 1999, 55, 7011. [2] T. Fukuyama, R. Yamaura, I. Ryu, Can. J. Chem, 2005, 83, 711. [3] J. H. Liu, J. Chen, C. G. Xia, J. Catal., 2008, 253, 50. [4] J. M. Liu, X. G. Peng, W. Sun, Y. W. Zhao, C. G. Xia, Org. Lett., 2008, 10, 3933.

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Light-driven Water Oxidation Catalyzed by a Dinuclear Ruthenium Complex

Yunhua Xu,a Lele Duan,a Lianpeng Tong,a Björn Åkermarkb and Licheng Sun a,* a Department of Chemistry, School of Chemical Science and Engineering, Royal Institute of Technology (KTH),

10044 Stockholm, Sweden, b Department of Organic Chemistry, Arrhenius laboratory, Stockholm University, 106 91 Stockholm, Sweden,

Email: lichengs@kth.

Inspired by the function of the oxygen-evolution center in Photosystem II, a few ruthenium-based complexes have been synthesized and shown to be efficient catalysts for water oxidation.1-4 Among them, however, only very few can drive this reaction with light.2,5 Recently we reported a dinuclear ruthenium complex containing a negatively charged ligand (see structure below) as an efficient catalyst for water oxidation in the presence of Ce(NH4)2(NO3)6 as chemical oxidant.6 In this presentation, we will present the catalytic activities of this complex toward light-driven water oxidation in the presence of Co(NH3)5Cl3 or Na2S2O8 as electron acceptor. Several ruthenium trisbipyridine derivatives that have different oxidation potentials were prepared and used as photosensitizers. Oxygen evolution was investigated by both Clark-type oxygen electrode and gas chromatography (GC).

2H2O O2

N N

N

N

OO

OO

Ru

N

N

N

Ru

N

N

N

PF6

photosensitizerelectron acceptorlight

References: 1. F. Liu, J.J. Concepcion, J.W. Jurss, T. Cardolaccia, J.L. Templeton, T. J. Meyer, Inorg. Chem. 2008, 47,

1727–1752; 2. P. Comte, M.K. Nazeeruddin, F.R. Rotzinger, A.J. Frank, M. Grätzel, J. Mol. Catal. 1989, 52, 63-84; 3. X. Sara, I. Romero, M. Rodriguez, L. Escriche, A. Llobet, Angew. Chem. Int. Ed. 2009, 48, 2842–2852; 4. Z. Deng, H.-W. Tseng, R. Zong, D. Wang, R. Thummel, Inorg. Chem. 2008, 47, 1835–1848; 5. J.L. Cape, J.K. Hurst, J. Am. Chem. Soc. 2008, 130, 827–829; 6. Y. Xu, T. Åkermark, V. Gyollai, D. Zou, L. Eriksson, L. Duan, R. Zhang, B. Åkermark, L. Sun, Inorg.

Chem. 2009, 48, 2717-2719.

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Preparation of sodalaite nanozeolite from rice husk ash without organic additives

Habibillah Younesi1, Zahra Ghasemi1, Hosein Kazemian2 1Department of Environmental Science, Faculty of Natural Resources & Marine Sciences, Tarbiat Modares

University, Noor, Iran; [email protected] 2Fuel Cell Institute,Universiti Kebangsaan Malaysia (UKM), 43600 UKM Bangi, Selangor,

Malaysia; [email protected]

Sodalite nanozeolite was successfully synthesized via hydrothermal method [1] with extracted silica source from rice husk ash. synthesized zeolite was characterized by XRF, XRD, SEM, EDX, FT-IR and BET. The XRF analysis results of extracted silica powder from rice husk ash by a suitable alkali solution was: LOI: 10.64, SiO2:87.988, Al2O3:0.477, Na2O:0.566 (wt%). According to XRD analysis, the extracted silica powder was amorphous (Fig 1a). The effect of crystallization time was investigated on the final product properties (Figs. 1bI, II, III). sodalite nanocrystal with crystal sizes ranging from 30 to 60 nm was synthesized at 60 °C and aging of 5 h, without adding any organic additives, while paying attention to the key factors for the synthesis of nanosized zeolite crystals [2, 3]. Figs. 3a and b indicate SEM images of the final products. The Si/Al and Na2O/SiO2 ratios of final products were 1.61 and 0.18, respectively. The results of BET analysis show that the specific surface area and external surface area of sodalite nanozeolite were to be 108.73 m2g-1 and 72.162 m2g-1, respectively.

(a)

(b)

Figure 1. (a) the XRD analysis of extracted silica powder (b) XRD patterns of Sodalite after (I) 1, (II) 2 and (III) 5 hours

(a)

(b)

Figure 3. SEM images of prepared nanozeolite Sodalite after (a) 2 and (b) 5 hours

[1] W. Fan, K. Morozumi, R. Kimura, T. Yokoi, T. Okubo, Synthesis of Nanometer-Sized Sodalite Without Adding Organic Additives, Langmuir 24 (2008) 6952-6958. [2] Y. Hu, C. Liu, Y. Zhang, N. Ren, Y. Tang, Microwave-assisted hydrothermal synthesis of nanozeolites with controllable size, Microporous and Mesoporous Materials 119 (2009) 306-314. [3] I. Schmidt, C. Madsen, C.J.H. Jacobsen, Confined Space Synthesis. A Novel Route to Nanosized Zeolites, Inorganic Chemistry 39 (2000) 2279-2283.

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Mesoporous Silica Supported Heteropoly Acids as Catalyst for the Conversion of Fructose into 5-Hydroxymethylfurfural

Y.M. Zhanga,b, V. Degirmencib, R.A. van Santenb, C. Lia, E.J.M. Hensenb

aState Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China

bSchuit Institute of Catalysis, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands

Renewable and abundant biomass-derived carbohydrates are important alternatives, not only for the sustainable supply of liquid fuels but also for valuable chemical intermediates. Among the many possible biomass-derived chemicals, 5-hydroxymethylfurfural (HMF) is a renewable platform for the production of fuels and fine chemicals. Therefore, preparation of HMF through the acid catalyzed dehydration reactions of sugars (Scheme 1) is one of the promising approaches to transform carbohydrates into useful chemicals1.

Scheme 1. Production of 5-hydroxymethylfurfural (HMF) from sugars through dehydration reactions.

Heteropoly acids (HPAs) have attracted considerable attention as acid catalysts for the clean synthesis of fine and specialty chemicals2. As far as the industrial production is concerned, the development of a heterogeneous system for sugar dehydrations has advantages over current approaches, such as ease of catalyst recovery, absence of corrosive mineral acids and continuous operation3.

In this part of work, as shown in Scheme 2 and Figure 1, we will present the production of HMF from fructose using mesoporous silica-supported heteropoly acids as catalyst in both DMSO and ionic liquid solvents.

Scheme 2. Fructose dehydration reactions based on the mesoporous Figure 1. Yields of HMF from fructose silica supported heteropoly acid catalyst. by acids catalyzed dehydration reactions in DMSO at 140 oC. References:

1. Y. R. Leshkov, J. A. Dumesic, et al., Science, 2006, 312, 1933-1937. 2. K. A. D. Rocha, E. V. Gusevskaya, et al., Appl. Catal. A: General, 2009. 352(1-2), 188-192. 3. X. H. Qi, M. Watanabe, et al., Green Chem., 2008, 10, 799–805.

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Structure determination of a tri-continuous mesoporous silica

Daliang Zhang1, Junliang Sun1, Yu Han2, Leng Leng Chng2, Lan Zhao2, Jackie Y. Ying2 d an Xiaodong Zou1*

1 Structural Chemistry and Berzelii Center EXSELENT on Porous Materials, Stockholm University, SE-106 91, Stockholm, Sweden

2 Institute of Bioengineering and Nanotechnology, 31 Biopolis Way, The Nanos, 138669 Singapore

Novel ordered porous materials with unique pore structures and pore sizes in the mesoporous range (2 – 50 nm) have attracted great scientific and industrial interest due to their appealing structures and potential applications in separation, purification, catalysis, devices etc. Until now, various mesoporous materials with distinct pore structures have been discovered such as one dimensional (1D) lamellar, two dimensional (2D) hexagonal, cage-type and bi-continuous pore structures. Bi-continuous mesoporous silica materials are characterized by two interwoven but disconnected mesoporous channels, which are separated by a single continuous silicate wall following triply periodic minimal surfaces (TPMS). However, more complex structures corresponding to tri- or multi-continuous TPMS was still undiscovered. Recently we reported a three dimensional (3D) hexagonal mesoporous silica, IBN-9, with a tri-continuous pore structure consists of three identical continuous interpenetrating channels. This most complex pore structure amongst all reported mesoporous materials was solved by 3D reconstruction of transmission electron microscopy images taken along different orientations. [1]

IBN-9 was synthesized by using a specially designed cationic surfactant template based on the co-assembly of organic surfactant molecules and inorganic silicate species in aqueous solutions. The unit cell was determined to be hexagonal from a tilting series of high-resolution transmission electron microscopy (HRTEM) images. A 3D electrostatic potential map was reconstructed by combining the HRTEM images along different directions. The pore structure is characterized by a series of zig-zag channels in parallel to the c axis. The zigzag channels are further connected by ‘ternate channels’ perpendicular to the c axis. The crystals of IBN-9 show well-defined fibre morphology, in which the zig-zag channels and ‘ternate channels’ are ultra-long and ultra-short, respectively. This might be particularly useful for separation and controlled release applications by offering distinct diffusion rates in different directions. The pore structure of IBN-9 is found as the first representation of the three-fold interwoven 3etc(187) net in a real material which has only be predicted mathematically before.

Two other mesophases IBN-6 (bi-continuous phase) and IBN-10 (2D hexagonal phase) were synthesized using the same surfactant by modifying the conditions for the synthesis of IBN-9. We analyzed the surface mean curvatures of the three different mesophases base on experimental electrostatic potential maps. The average mean curvature increases from the cubic IBN-6 to the 3D hexagonal IBN-9 and to the 2D hexagonal IBN-10 which shows IBN-9 is an intermediate phase between the bi-continuous phase and the 2D hexagonal phase. Reference: 1. Y. Han, D. Zhang, L.L. Chng, J. Sun, L. Zhao, X. Zou, J.Y. Ying “A tri-continuous mesoporous material with a silica pore wall following a hexagonal minimal surface” Nature Chemistry 1, 123 – 127 (2009).

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