Time Program
09:00-09:20 Registration
09:20-09:30 Welcome Remarks by HOD
Session 1: Student Chair
09:30-10:00 Prof. Rodney A. Fernandes Protecting-Group-Free Synthesis of Natural Products:
A Step Toward Economy and Efficiency in Synthesis
10:00-11:00 Student Oral Presentation
1 Ritutama Ghosh Biophysical Insights into Formation and Prevention of Amyloid Hydrocolloids:
Implications in Neurodegenerative diseases
2 Sunil Pulletikurti Role of Carbonyl Group at C7 Position of Endo-norbornene Derivatives on
Olefin Metathesis: Synthesis of Polycycles and Heterocycles
3 Vishal Kotha Low-Temperature Synthesis of K-substituted LaMnO3
4 Aarti Sindhu Theoretical Investigation of Electronic Energy Transfer (EET) in the
Photosynthesis Process using Semi-classical Method
5 Parichita Saha A Universal Tetrapeptide Scaffold for Tunable Transmembrane Cation
Transport
6 Archita
Bhattacharjee Meso/Macro Porous Liquid for CO2 Capture, Storage and Catalytic Conversion
7 Asmita Sen Probing the Mechanistic Study of Aliphatic C-H Nitration By SYRB2:
QM/MM Approach
8 Pravas Dolui Ligand Enabled Palladium Catalyzed γ -C(sp3)-H Arylation of Free Carboxylic
Acid
9 Nandini Sharma Allosteric Regulation Mechanism of Purine Biosynthetic Pathway Enzyme
10 Santanu Jana Synthesis of Trehalose Glycolipids
11 Amitrajait Mukherjee Do All Quantum-dots in an Ensemble have the Same
Origins of Photo-blinking?
12 S. Senthilkumar Synthesis and Crystal Structures of Carboxylate and Phosphonate Metal–
Organic Frameworks (MOFs)
11:00-11:15 Group Photo and Tea
11:15-11:50 Poster Session
Session 2: Student Chair
11:50-12:30 Student Oral Presentation
13
Itisha Dwivedi Resistive Random Access Memory Devices by Different Organic–Inorganic
Hybrid Perovskites
14 Geetanjali Sontakke
Rh(II)-Catalyzed Denitrogenative Transannulation of N-Sulfonyl-1,2,3-
triazolyl Cyclohexadienones for the Synthesis of Benzofurans and Cyclopropa[cd]indole-carbaldehydes
15 Vinodhini G A Systems Biology Approach to Understand Effect of Serum Level on
Mammalian Cell Cycle Progression Variability
16 Harish S. Kunchur PdII, and PtII Assisted Tandem P−C Bond Breaking and P−N Bond Formation
Reactions from an Amide Functionalized Bisphosphine: Synthesis,
Mechanistic, and Structural Studies
17 Yuvraj Dangat Exploring the Enantioselectivity of Rh-Yanphos Catalyzed -methyl Styrene
Hydroformylation : Added Insights from Theory
18 Shalini Tripathi Influence of Counter-Anion on the Zero Field Splitting of Tetrahedral Co(II)
Thiourea Complexes
19 Priyanka Deshmukh Synthesis of Methyleugenol and Estargol Induced DNA Damages to Study
Translesion DNA Synthesis
20 Santosh Ranga Excess Electron Interactions with Solvated GC Base Pair: QM/MM Study
12:30-13:00 Prof. Anindya Datta Key factors for design of solid emitters by aggregation of organic
fluorogens.
13:00-14:00 Lunch Time
Session 3:Student Chair
14:00-14:30 Prof. Gopalan Rajaraman Role of Ab initio Calculations in the Design of Transition Metal
Based Single-Ion Magnets
14:30-15:25 Student Oral Presentation
21 Sanyog Kumari Stereoselective Synthesis of Tetrahydrocyclohepta[b]indole Derivatives by
Cascade Radical Cyclization of 3-Propargylated-2-alkenyl indoles
22 Anish Chakraborty A Dressed Coupled Cluster Theory for Molecular Energetics: H-Bonded and
Strongly Correlated Systems
23 Farheen Fatima Khan Redox Assisted Oxidative C-C Cleavage in Diruthenium Complexes of 2,2'-
Pyridil
24 Hemen Gogoi Solvent Mediated Relaxation Dynamics of Core-Shell Au-SiO2 Nanoparticles
25 Prosenjit Isar Facile Synthesis of Fused Core-Modified Sapphyrins
26 Ramalingam Kailasham
Wet and Dry Internal Friction Can be Measured with the Jarzynski Equality
27 Amit Bhowmik Iron(III)/O2-Mediated Regioselective Oxidative Cleavage of 1-Arylbutadienes
to Cinnamaldehydes
28 Pranav Adhyapak Biophysical Insights into the Spatially OrganizedCell Envelope of
Mycobacterium Smegmatis.
29 Ratika Maini Synthesis of Hole Transport Materials Using Pentiptycene Core as the Building
Block
30 Ashiv Narula Carrageenan Beads Incorporated Fluorophoric calix[4]arene Conjugate for Selective, Efficient, Reversible and Fingerprint Detection of Trinitrophenol
31 Sohan Lal Design and Synthesis of Highly Dense Homocubane Derivatives
15:25-16:25 Poster Session
16:25-16:45 High Tea
Session 4: Student Chair
16:45-17:15 Prof. M. S. Balakrishna IYPT 2019 Talk: It is all about the Periodic Table
17:15-18:00 Teaching Awards, Certificate distribution, and Concluding Remarks with Feedback
18:00 Onwards
Cultural Program
Poster Details
Poster No. Student Name Title
1 Amruta Joshi Interaction of proteins and drugs with non- ionic surfactant.
2 Sushil Swaroop
Pathak
Exceptional self-assembly of Ag and Au nanoparticles in
cubic arrangement
3 Chinmay S Pradhan Modelling non-adiabatic and quantum effects near metal
surface
4 Umatai Hale Diketopiperazines as ion transporters and templates for
functionalized membranes
5 Naveen Kumar P M
Investigating the interactions and resultant micro-structure of
protein-polymer surfactant bioconjugates with nematic liquid
crystalline phase
6 Reshma Jose How the spin states control the gas adsorption properties in
Cr-BTT based metal organic frameworks
7 Jyoti Prasad Biswas Co‐ordination assisted distal C−H alkylation of fused
heterocycles
8 Ruchika Bhujbalrao Probingmechanism of ribosomal methyltransferases involved
in antibiotic resistance
9 Kabita Pradhan Studies towards total synthesis of tetrasaccharide repeating
unit of Vibrio cholerae O43
10 Jaladhar Mahato Spatially and spectrally resolved FRET microscopy
11 Tejamani Behera Spatially synchronous fluorescence blinking and flickering of
entire perovskite micro-rods
12 Anuj Kumar Thermally labile layered alkali metal iso-propyl phosphate
13 Ananya Shah Nanostructured carbons for solar thermal conversion for
highly efficient and rapid water evaporation
14 Amitava Giri Unraveling the importance of cell to cell interactions and
underlying fluctuations in neural cell fate decisions
15 Anurag Singh
Palladium-catalyzed highly diastereoslective cascade
dihalogenation of alkyne-tethered cylcohexadienones via
umpolung of palladium enolate
16 Kote Basvaraj Shivaji Phosphine appended with N-heterocycles: Synthesis,
transition metal chemistry and catalytic applications
17 Dipak Fartade
Stereoselective synthesis of medium ring [1,n]-heterocycle-
fused chromenes using 7/8/9-*Endo-Dig* And 7/8-*Exo-
Dig* hydroalkoxylation-formal-[4+2]-cycloaddition cascade
18 Satendra Sahgal Synthesis and biophysical evaluation of G-quadruplex
stabilizing and i-motif destabilizing ligands
19 Divya Tripathi Water mediated electron attachment to nucleobases
20 Mohd Wasim
Importance of transition and lanthanide metal Complexes:
Application in magnetism, catalysis, device fabrication and in
biological system
21 Dashrath Jangid and
Ashvin Gangani
Brønsted Acid-Mediated Reaction in Organic Synthesis:
Synthesis of Coumarin and Butenolide 4-Sulfonates
and 4-Pyranones
22 Fariyad Ali Ultrafast carrier relaxation dynamics of Cu doped
CdSenanotetrapods
23 Mohd Asif Ansari
Di, Tri and Tertanuclear Ruthenium Complexes of a
Heterocyclic and Quinonoid Bridging Ligand: Valence and
Spin Alternatives for the Metal/Ligand/Metal Arrangement,
Non-Innocence and Mixed Valency
24 Avisikta Sinha Synthesis and studies of dibenzothiophene/ dibenzofuran
embedded expanded macrocycles
25 Ligesh T Dynamics of a self-propelled janus particle in a sea of
polymers
26 Jyoti Agawane Process intensification through continuous flow
27 Aswin Srivatsav T Dynamical organisation of compositionally distinct inner and
outer membrane lipids of Mycobacteria
28 Sirilata Polepalli Synthesisand applications of new protein- Inorganic hybrid
materials
29 Chenikkayala
Sivasankara
One-pot construction of functionalized
spirodihydronaphthoquinone-oxindoles via Hauser-Kraus
annulation of sulfonylphthalide with 3-alkylideneoxindoles
30 Shreyata Dey
Stereodirecting Mesoioninc Singlet Carbene Complexes:
Synthesis and Application in Asymmetric Catalysis
31 Priyanka Sakhare
Copper catalyzed oxidative C−C bond cleavage of 1,2-
Diketones: A direct route to 1,8 Naphthalimides, Biphenyl-
2,2’-Dicarboxamides and N-Heterocyclic amides
Faculty Oral Talks Abstracts
Protecting-Group-Free Synthesis of Natural Products:
A Step Toward Economy and Efficiency in Synthesis
Rodney A. Fernandes*
Department of Chemistry, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India
Protecting-group-free (PGF) synthesis enables step economy and increases the efficiency of
synthesis.1 Our research in the synthesis of many natural products designing PGF based strategies
have resulted in shorter sequences than that known in the literature. The stereoselective total synthesis
of the following listed natural products2-6 will be discussed.
References:
1. Protecting-Group-Free Organic Synthesis: Improving Economy and Efficiency, Fernandes,
R. A. Ed. John-Wiley & Sons, 2018.
2. (a) Fernandes, R. A.; Kattanguru, P. J. Org. Chem. 2012, 77, 9357. (b) Fernandes, R. A.;
Kattanguru, P. Asian J. Org. Chem. 2013, 2, 74. (c) Chaudhari, D. A.; Kattanguru, P.;
Fernandes, R. A. RSC Adv. 2015, 5, 42131.
3. Kunkalkar, R. A.; Laha, D.; Fernandes, R. A. Org. Biomol. Chem. 2016, 14, 9072.
4. Nallasivam, J. L.; Fernandes, R. A. Org. Biomol. Chem. 2017, 15, 708.
5. (a) Ramakrishna, G. V.; Fernandes, R. A. Org. Lett. 2019, 21, 5827. (b) Ramakrishna, G. V.;
Fernandes, R. A. J. Org. Chem. 2019, DOI: 10.1021/acs.joc.9b02461.
6. Kunkalkar, R. A.; Fernandes, R. A. J. Org. Chem. 2019, DOI:10.1021/acs.joc.9b01952.
Key factors for design of solid emitters by aggregation of organic fluorogens
Tuhin Khan, Souradip Dasgupta and Anindya Datta
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, India
Email: [email protected]
Aggregation induced enhancement of emission (AIEE) of fluorogenic molecules been studied using
steady state and time resolved spectroscopy, starting with salophen, a fluorogenic Schiff base.
Fluorescence quantum yield and lifetime of salophen increase by orders of magnitude upon
complexation and in solid form/ matrix. The extent of enhancement is significantly more in its
monomeric Al3+ complex (SalAl+) than in its dimeric Zn2+ complex (SalZn).1 Interestingly,
fluorescence is quenched in the SalAl+ crystals. These trends are rationalized in the light of molecular
arrangement of salophen and its complexes in their pure solid forms.2 Introduction of alkoxy groups
in salophen ring is found to alter not only the photophysics, but also molecular packing of the
molecules in their crystals, leading to a higher emissivity of the Al3+ complexes in their crystalline
form.3 More recently, we have studied other Schiff bases, in which Zn complexes are dimeric, but the
ligand molecules are not stacked. These complexes turn out to be significantly more emissive than
the free ligand, thereby supporting the role of p-stacking in determining the emissivity of these
complexes. Careful selection of structural and electronic properties is required to optimize emissivity
of similar complexes and free ligands in their solid state.4
References
(1) Khan, T.; Vaidya, S.; Mhatre, D. S.; Datta, A. The Prospect of Salophen in Fluorescence
Lifetime Sensing of Al3+. J. Phys. Chem. B 2016, 120 (39), 10319–10326.
(2) Khan, T.; Datta, A. Impact of Molecular Arrangement and Torsional Motion on the
Fluorescence of Salophen and Its Metal Complexes. J. Phys. Chem. C 2017, 121 (4), 2410–
2417.
(3) Khan, T.; Datta, A. Enhanced Fluorescence with Nanosecond Dynamics in the Solid State of
Metal Ion Complexes of Alkoxy Salophens. Phys. Chem. Chem. Phys. 2017, 19 (44), 30120–
30127.
(4) Dasgupta, S.; Khan, T.; Datta, A. Excited State Dynamics of Fluorogenic Molecules,
in Advances in Spectroscopy: Molecules to Materials, Singh, D. K.; Das, S.; Materny, A. eds.
Springer 2019
Role of Ab initio Calculations in the Design of Transition Metal Based Single-Ion
Magnets
Gopalan Rajaraman
Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai.
Email: [email protected]
Molecular magnetism is one of the vastly growing research fields with an aim to design the molecules
and materials with tunable magnetic and electronic properties.Error! Reference source not found.
Their synthesis, characterization and implementation as devices which creates lively crossroad among
chemistry, physics and material science: a multidisciplinary research field. These molecules have wide
spread potential applications ranging from magnetic storage devices, spintronics, Q-bits in quantum
computing to magnetic coolants.Error! Reference source not found. Single-molecule magnets
(SMMs) are the molecules which show slow relaxation of magnetization below the critical
temperature and exhibit hysteresis loop similar to classical magnets. SMMs offer key advantage over
classical magnets due to their light weight, solubility and multifunctional behaviour. Theoretical tools
are indispensable in this arena2 for understanding the observed magnetic properties. The strength of
these methods is not only limited rationalization but also to predict novel molecules which can exhibit
superior magnetic properties. In this presentation, I will research effort undertaken in our group
towards achieving this goal.2
References:
1. R. Sessoli, D. Gatteschi, A. Caneschi, M. A. Novak, Nature, 1993, 365, 141.
2. Singh S. K. and Rajaraman, G. Nature Commun. 2016 7:10669, Gupta,S.K.; Rajeshkumar,T.;
Rajaraman,G. and Murugavel,R. Chem. Sci., 2016,7, 5181-5191; Singh,M.K.;Yadav,N.;
Rajaraman,G. Chem. Commun. 2015,51, 17732-17735. T. Gupta, G. Rajaraman Chem.
Comm., 2016, 52, 8972.
3. Rajaraman and Murrie and co-workers, Chem. Sci., 2018, 1551; Chem. Sci., 2019, 6354.
Rajaraman and co-workers, Chem. Eur. J., 2019, DOI: 10.1002/chem.201903618.
It is all about the Periodic Table
M S Balakrishna
Department of Chemistry, Indian Institute of Technology Bombay,
Powai, Mumbai 400076
UNESCO has designated 2019 as the International Year of the Periodic Table to mark 150th
anniversary of the Mendeleev periodic table. Periodic table is a symbol of learning and an iconic
image of science. It is an essential and a complete tool to understand science in all aspects including
day-to-day life. The present periodic table with 118 elements, all known and named, includes 94
natural and 24 man (woman) made elements.
Mendeleev published his periodic table, popularly known as Mendeleev Periodic Table, in 1869, in
which all known elements have been arranged in increasing order of their atomic weight with a
statement: “The properties of the elements are a periodic function of their atomic weight”. Before
Mendeleev proposed his periodic table many researchers and chemists made attempts to arrange the
known elements in an order along with their atomic weights, and other physical and chemical
properties. Among them the prominent ones being: Lavoisier, Berzelius, Dobereiner, Newlands and
Meyer. Later Ramsay and physicist Releigh discovered all inert gases, and trans-uranium elements
by Seaborg, Oganessian, Ghiorso and others. The talk includes brief discussion on historic
developments along with the fascinating stories about the discovery of a few elements.
Student Oral Talks Abstracts
Biophysical Insights into Formation and Prevention of Amyloid Hydrocolloids:
Implications in Neurodegenerative diseases
Ritutama Ghosh and Nand Kishore
Abstract: Aggregation and disorder in proteins is associated with neurodegenerative disorders such
as, Alzheimer’s, Parkinson’s, Huntington’s and prion diseases.1 Accumulation of protein fibrils leads
to amyloidosis, though recently their catalytic properties are also being explored in combination with
metals. Cross-β sheet quaternary structures are adopted by the amyloids. The effect of anticancer
drugs on fibrillation/aggregation properties of the transport protein bovine serum albumin has been
studied to understand how molecules act as inhibitors in the process of aggregation. The process of
fibrillation/aggregation was monitored by thioflavin T assay, 8-Anilino-1-naphthalenesulfonic acid
assay, transmission electron microscopy and dynamic light scattering. The energetics of interactions
of the potential inhibitors has been studied with the protein at various stages of fibrillation by
isothermal titration calorimetry. The extent of structure/conformation induced by the inhibitors has
been studied by differential scanning calorimetry along with circular dichroism spectroscopy. It is
observed that anticancer drugs altretamine, 5-fluorouracil and hydroxyurea, act as inhibitors of
fibrillation in serum albumin and therefore can also be useful in treating the neurodegenerative
diseases. The thermodynamic signatures of the drugs with the protein thus obtained at native,
nucleation/elongation and matured stages of the fibrillation/aggregation have enabled an
understanding of mechanistic details of prevention of fibrils, identification of the functional groups
responsible for inhibition and hence establishing structure-property-energetics relationships.
Reference:
1. Chatani, E., and Yamamoto, N. 2018. Recent progress on understanding the mechanisms of
amyloid nucleation. Biophys. Rev., 10, 527-534.
Role of carbonyl group at C7 position of endo-norbornene derivatives on olefin
metathesis: Synthesis of polycycles and heterocycles
Sunil Pulletikurti, Kotha Sambasivarao*
Abstract: Role of carbonyl group at C7 position of endo-norbornene derivatives on olefin metathesis
was not studied. Here, we demonstrated that the presence of carbonyl group at C7 position is
preventing to undergo metathesis of olefin of endo-norbornene derivatives due to complexation
between metal alkylidene and olefin of endo-norbornene derivatives via DFT studies, time-dependant
NMR studies and ESI-MS analysis. DFT studies depicts that the orientation of metal alkylidene is
near perpendicular to that of norbornene olefin. Time-dependent NMR studies showed the presence
of a new proton signal in the metal alkylidene region, which indicates the formation of metal complex
with carbonyl group of substrate. These observation were further proved by ESI-MS analysis (Figure
1a). Later these endo-keto norbornene derivatives were reduced to hydroxyl derivatives which gives
us the [6/5/6] carbo-tricyclic, [6/5/6] oxa-tricyclic derivatives and [5/6/5] carbo-tricyclic derivatives
of a class of natural products on ring-rearrangement metathesis (Figure 1b).
References
1. Sanford, M. C., Love, J. A., Grubbs, R. H. J. Am. Chem. Soc. 2001, 123, 6543.
2. Eaton, P. E., Sidhu, R. S., Langford, G. E., Cullison, D. A., Pietruszewski, C. L. Tetrahedron
1981, 37, 4479.
3. Kotha, S., Pulletikurti, S. RSC Adv. 2018, 8, 14906.
Low-Temperature Synthesis of K-substituted LaMnO3
Vishal Kotha and Leela Srinivas Panchakarla*
Abstract: LaMnO3 (LMO) is an antiferromagnetic insulator, but the substitution of La3+ by alkaline
earth metals makes it ferromagnetic metallic system. Doping of the La site in LMO by divalent
cations (e.g., Ba2+, Sr2+, and Ca2+) is known for the last five decades. In these manganites, unique
phenomena like charge, spin, and orbital ordering take place. However, recently, the discovery of
colossal magnetoresistance (CMR) in these doped LMO has triggered the attention of the scientific
community. The limitation of not knowing to synthesize in controlled morphology mainly in one-
dimensional is a challenge to apply in the advanced technologies. We have approached via solution-
based synthesis, i.e., the hydrothermal method where one can have reasonable control over the size
and morphology of the compound. For the first time, our studies made us understand the crystal
growth mechanism, which is quite different from the classical nucleation and growth mechanism
followed by the tri-component nucleation.
Reference:
1. Shivkumara C. Subraya M. Solid state Sci. 2001,3,43
2. Markovich, V.; Jung, G.; Fita, I.; Mogilyansky, D.; Wu, X.; Wisniewski, A.; Puzniak, R.;
Froumin, N.; Titelman, L.; Vradman, L.; Herskowitz, M.; Gorodetsky, G. J. Phys. D. Appl.
Phys. 2008, 41, 185001
3. Kuepper, K.; Falub, M. C.; Prince, K. C.; Galakhov, V. R.; Troyanchuk, I. O.; Chiuzbaian, S.
G.; Matteucci, M.; Wett, D.; Szargan, R.; Ovechkina, N. A.; Mukovskii, Y. M.; Neumann, M.
J. Phys. Chem. B 2005, 109, 9354.
4. Wang, X. R.; Li, C. J.; Lü, W. M.; Paudel, T. R.; Leusink, D. P.; Hoek, M.; Poccia, N.;
Vailionis, A.; Venkatesan, T.; Coey, J. M. D.; Tsymbal, E. Y.; Ariando; Hilgenkamp, H.
Science 2015, 349, 6249.
5. Shivakumara, C.; Bellakki, M. B. Bull. Mater. Sci 2009, 32, 443
Theoretical Investigation of Electronic Energy Transfer (EET) in the
Photosynthesis Process Using Semi-classical Method
Aarti Sindhu and Amber Jain
Abstract: The process of photosynthesis has a remarkable efficiency in the energy transfer from the
absorbance site to reaction centre of the system. In a recent spectroscopic experiment (Engal GS, et
al. (2007), Nature 446, 782-786), on Fenna–Mathews-Olsan (FMO) complex, the wavelike transfer
of energy from one site to another have been observed for half of a picosecond time at cryogenic
temperature and these quantum beatings were considered to be responsible for the efficient and robust
energy transfer in the photosynthesis. Further, there have been several theoretical attempts to simulate
the system and extract out the roots of these observed quantum beatings, and to find whether these
are really related to the efficiency or robustness of the process. In the present work, we used semi-
classical method (Surface Hopping) to simulate the FMO system using a model Hamiltonian and
compare the results with the exact numerical method (Hierarchical Equation of motion (HEOM)) that
have been done previously on the same system. We have been working on the system to target
multiple aims. The most important among is to draw out the significance of Nuclear Quantum Effects
(NQE) which is the advantage of using semi-classical method over exact HEOM. And it is found that
for some pairs of FMO sites, NQE plays an important role.
A Universal Tetrapeptide Scaffold for Tunable Transmembrane Cation
Transport
Parichita Saha and Dr. Nandita Madhavan*
Abstract: Ion transporters play important role in maintaining the physiological activities in organic
systems. Natural ion transporters regulate the entry and exit of ions across cell membrane and thus
maintain the proper concentration of important ions in the body fluids.1 The importance of the
synthetic ion transporters and receptors lie in the fact that they help in understanding the features and
functions of their otherwise unstable natural counterparts.2 Herein we explore the relationship
between ion selectivity and scaffold design in peptide templates.3 We report a small tetrapeptide
scaffold for cation transport. The selectivity of the designed peptides has been tuned by varying the
aromatic units incorporated in the tetrapeptide template. Pybox incorporated tetrapeptides were found
to transport Cu(II) while calcium transport was achieved with scaffolds containing both triazole and
pyridine units (Figure 1).4
Figure: Tuning ion selectivity based on aromatic units present in peptide scaffolds
References:
1. B. Hille, Ion Channels of Excitable Membranes, 3rd ed., 2001.
2. E. Gouaux and R. MacKinnon; Science., 2005, 310, 1461-1465.
3. D. Basak, P. Saha and N. Madhavan, ChemistrySelect., 2018, 33, 9731-9735.
4. P. Saha and N. Madhavan, unpublished results.
Meso/Macro Porous Liquid for CO2 Capture, Storage and Catalytic Conversion
Archita Bhattacharjee, and Kamendra P.Sharma*
Abstract: Permanent pores combined with fluidity renders new properties to porous liquids
otherwise not seen in porous solids. In my talk I will show the design and development of a new class
of water-less porous liquid comprising a mixture of polymer-surfactant modified hollow silica
nanorods and carbonic anhydrase enzyme. The composite mixture having a melting point transition
at ~ 20 °C, can be used to sequester/adsorb gaseous CO2 (5.5 cc/g) at 273K and 1 atm pressure.
Further, we show using a combination of turbiditimetry, optical and electron microscopy experiments
that, carbonic anhydrase, can convert the slowly releasing carbon dioxide into carbonate ion. This
reaction can be monitored by the formation of CaCO3 crystals formed due to reaction of carbonate
ion and pre-dissolved CaCl2 salt (68μM) in the composite liquid. The growth of calcite and aragonite
crystals (as observed from XRD) over 48 hrs leads to ~75% decrease in the transmittance after
sequestration of CO2. Moreover, we show CO2 storage capabilities of the water-less composite
porous liquid by trapping the gas within the hollow silica nanorods at -60 °C i.e. below the glass
transition temperature of the system.
References:
1. Zhang, J., Chai, S.H., Qiao, Z.A., Mahurin, S.M., Chen, J., Fang, Y., Wan, S., Nelson, K., Zhang,
P. and Dai, S., Angew. Chem. Int. Ed., 2015, 54, 932-936. 2. Jo, B.H., Seo, J.H., Yang, Y.J., Baek, K., Choi, Y.S., Pack, S.P., Oh, S.H. and Cha, H.J., ACS
Catal., 2014, 4, 4332-4340.
Probing the Mechanistic Study of Aliphatic C-H Nitration by SYRB2: QM/MM
Approach
Asmita Sen, Gopalan Rajaraman*
Abstract: Syringomycin biosynthesis enzyme 2 (SyrB2) belongs to the αKG-dependent halogenase
family. It is found to chlorinate the γ-carbon of L-threonine in the biosynthesis of a phytotoxin called
syringomycin E. Recently, Bollinger et al.1 showed that wild type halogenase SyrB2 also found to
be able to perform C−N bond formation reactions by substituting the native halide ion with the
nitrogenous anions N3 − and NO2 − . These results hint that the Cl is not by itself the cause of the
selectivity of halogenation over hydroxylation, and they thereby underscore the need to understand
why, unlike other similar enzymes, C−H activation does not end with hydroxylation. In this study,
we have focused on the mechanistic aspect of the aliphatic nitration of the L-threonine substrate by
the SyrB2 protein. I have studied small model (with active site only), large model (active site along
with the surrounding amino acid residues that involve with the active site via hydrogen bonding) and
QM/MM study with the entire protein matrix. Calculation on the realistic system i.e. QM/MM
calculation shows that nitrated product is formed exclusively. Our Small model calculations reveal
that there is a competitive nitration with hydroxylation although nitration is favored over
hydroxylation. With large model, the selectivity increases and the result resembles with the QM/MM
results. Based on these calculations we concluded that, we can continue our study with large model
and we have the comparative study with varying substrate and found that HAA step is the rate limiting
one and the reactivity is Aba-S-SyrB1> Thr- S-SyrB1 > Nva-S-SyrB1. We have explored the
reactivity in presence of external oriented electric field.
Reference:
1. Matthews, M. L.; Chang, W.-c.; Layne, A. P.; Miles, L. A.; Krebs, C.; Bollinger Jr, J. M. Nat
Chem Biol2014, 10, 209-215.
H2O
His235
Cl
His116
Ligand Enabled Palladium Catalyzed γ-C(sp3)-H Arylation of Free Carboxylic
Acid
Pravas Dolui, Debabrata Maiti*
Abstract: C-H functionalization of aliphatic carboxylic acids without attaching exogenous auxiliary
has been so far limited at the proximal γ-position1. Herein, we demonstrate a ligand enabled
palladium catalyzed first regioselective distal γ-C(sp3), γH functionalization of aliphatic carboxylic
acids without incorporating an exogenous directing group2. Aryl iodides containing versatile
functional groups including complex organic molecules underwent the γ-C(sp3) γH arylation reaction
with good to excellent yields. Interestingly, weak coordination of carboxylate group can be further
extended for sequential hetero di-arylation.
Reference:
2. Zhu, Y., Chen, X., Yuan, C., Li, G., Zhang, J., Zhao, Y. Nat. Commun. 2017, 8, 14904.
3. Dolui, P., Das, J., Chandrashekar, H. B., Anjana, S. S., Maiti, D. Angew. Chem. Int. Ed.
2019,
Allosteric Regulation Mechanism of Purine Biosynthetic Pathway Enzyme
Nandini Sharma1, Padmani Sandhu1, Navjeet Ahalawat2, Jagannath Mondal2 and Ruchi Anand1,*
Abstract: Formylglycinamidine (FGAM) synthetase, a bi-functional enzyme from purine
biosynthetic pathway has been studied for the investigation of allosteric regulation controlled by a
long flexible loop present approximately ~30Å apart from the catalytic site. FGAM synthetase from
Salmonella typhimurium encoded by purL gene (StPurL) is a single polypeptide of 143 kDa size,
composed of glutaminase, FGAM synthetase, N- terminal and a linker domain [1]. Glutamine
hydrolysis occurs in the glutaminase domain releasing ammonia which is further migrated towards
the FGAM domain via a ~25Å long hydrophobic tunnel where FGAR
(formylglycinamideribonucleotide) to FGAM (formylglycinamidineribonucleotide) conversion
happens [1]. The FGAR binding site is hypothesized to be capped by a long flexible disordered loop
during the course of reaction. Employing a combination of biochemical and X-ray crystallographic
studies, we show that long distance communication, between distal active sites, is initiated by an
allosteric switch that resides in a this conserved catalytic-loop. Further, molecular dynamics
simulations help to delineate the transient states that bring out central role of non-functional N-
terminal domains. We show that carefully orchestrated conformational changes, facilitated by an
interplay of dynamic interactions at the allosteric switch and adaptor-domain interface control
reactivity as well as concomitant formation of the ammonia tunnel. The study asserts that substrate-
channeling is modulated by allosteric hot-spots that alter protein energy landscape thereby, allowing
it to adopt transient conformations paramount for function.
Reference:
1. R.Anand, A. A.Hoskins, J.Stubbe & S. E.Ealick (2004) Domain Organization of Salmonella
typhimurium Formylglycinamide Ribonucleotide Amidotransferase Revealed by X-ray
Crystallography. Biochemistry 43 (32), 10328-10342.
Synthesis of Trehalose Glycolipids
Santanu Jana, Vikram A. Sarpe and Suvarn S. Kulkarni*
Abstract: M. tuberculosis sulfolipids SL-1, Ac2SGL and SL-3 are highly immunogenic and potential
vaccine candidates.1 In the course of our studies directed towards synthesis of trehalose
glycoconjugates,2 We established a novel methodology for the regioselective O6 acylation of the 2,3-
diacyl trehaloses. The methodology was employed to access M. tuberculosis sulfolipid SL-3, related
triester glycolipid analogues, and to achieve the first total synthesis of the tetraacylated trehalolipid
from M. paraffinicum.3 These glycolipids are potential candidates for serodiagnosis and vaccine
development for tuberculosis.
Another class of fungal glycolipids emmyguyacins A and B inhibit the pH dependent conformational
change of hemaglutinin A during replication of the Influenza virus.4 Structurally, compound 1 has a
gluco-galacto trehalose core and 2 is a gluco-gluco diastereomer (Figure 1). Both glycolipids contain
a novel acid chain at the 3-position, 17-oxalyloxydocosanoic acid. Our efficient route, which involves
regioselective functionalization of trehalose and the synthesis of R and S enantiomerically pure side
chain starting from one chiral synthon S-epichlorohydrin, allows rapid access to adequate amounts of
chemically pure emmyguyacin analogues including the desoxylate derivatives for SAR studies.5
References:
2. Goren, M. B. Biochim. Biophys. Acta. 1970, 120, 116-126.
3. Sarpe, V. A.; Kulkarni, S. S. Org. Lett. 2014, 16, 5732-5735.
4. Sarpe, V. A.; Jana, S.; Kulkarni, S. S. Org. Lett. 2016,18, 76-79.
5. Boros, C.; Katz, B.; Mitchell, S.; Pearce, C.; Swinbank, K.; Taylor, D. J. Nat. Prod. 2002, 65,
108–114.
6. Jana, S.; Sarpe, V. A.; Kulkarni, S. S. Org. Lett. 2018, 20, 6938–6942.
Do All Quantum-Dots in an Ensemble have the Same Origins of Photo-blinking?
Amitrajit Mukherjee and Arindam Chowdhury
Abstract: Temporally random photo-luminescence (P-L) intermittency (or blinking) in
semiconductor nanocrystals (NCs) is generally considered to be intensity fluctuations between
‘bright’ (‘On’) and ‘dark’ (‘Off’) states, however, rarely do individual quantum-dots (QDs) exhibit
such telegraphic signal. Interestingly, while none of the blinking trajectories are identical for the same
material and morphology, even their intermittency pattern and emissivity often varies drastically from
one QD to another under identical experimental conditions. This poses a serious problem as the
exponent values (𝑚𝑂𝑛/𝑂𝑓𝑓) of the single-particle On-/Off-time durations (𝑃(𝑡𝑂𝑛/𝑂𝑓𝑓)) are used to
validate mechanistic models of NC blinking. To probe the extent of heterogeneity of blinking
processes, we sub-classify an ensemble (1040) of QDs based on the emissivity of individual QDs,
and subsequently compare the (sub)ensembles’ behaviors. The distributions of relevant blinking
parameters constructed for Mn+2 doped ZnCdS QDs reveal a remarkable variation in 𝑚𝑂𝑛/𝑂𝑓𝑓
amongst, as well as within various sub-ensembles. Our results therefore imply that multiple blinking
mechanisms being operational amongst various QDs in the ensemble. We conclude that investigation
and analyses of a large number of QDs, albeit for a limited time-span of few decades, is crucial to
characterize possible blinking mechanisms or probe heterogeneity therein.
Synthesis and Crystal Structures of Carboxylate and Phosphonate Metal–
Organic Frameworks (MOFs)
S. Senthilkumar and R. Murugavel
Abstract: The long-standing dream of researchers to be able to link molecules together into
crystalline, extended (infinite) 2D and 3D structures is now understood by the establishment of
coordination chemistry through the discovery and development of metal-organic frameworks
(MOFs). These framework materials allow compositional and structural diversity beyond
conventional solid-state materials. However, at the end of the 19th century, Alfred Werner’s work on
the geometric aspects of how ligands bind to metal ions has given rise to organometallic, bioinorganic
and cluster chemistries. By stitching together organic and inorganic units into crystalline porous
frameworks, the connectivity, spatial arrangement, and geometry of those molecular complexes can
now be fixed in space and become directly addressable. The fact that MOFs are porous provides
additional space within which molecules can further be transformed and their chemistry is controlled.
Also the process of modifying frameworks without altering their underlying connectivity, yields
isoreticular frameworks. In this regard, here we have synthesised two carboxylate and two
phosphonate centred MOFs. First one is, sterically encumbered ditopic C2-symmetric ligand based
isopropyl group decorated hydrophobic isoreticular 2D and 3D Zn-framework. And the second one
is C3-symmetric ligand tris(methylene))tris(phosphonic acid) based Al as well as Mg-frameworks.
All these frameworks are well characterised and clear structure obtained by single crystal X-ray
diffraction. These two phosphonate frameworks candidates are considered as a good proton-
conducting material because of their high crystallinity and well-designed pores for proton-conducting
pathways.
Resistive Random Access Memory Devices by Different Organic–Inorganic
Hybrid Perovskites
Itisha Dwivedi, Pramiti Hui and Chandramouli Subramaniam
Abstract: Resistive memory devices, and in particular memories based on low-cost, solution-
processable and chemically tunable organic materials, are promising alternatives explored by the
industry. Such devices exhibit high switching voltage and thereby require higher operational power.
This also leads to resistive dissipation in the form of heat, leading to overheating of the devices and
adversely affects their reliability. Addressing this demand, we report the organic– inorganic hybrid
perovskite materials in Resistive memory devices with a remarkable appearance of switching effect
which shows high reproducibility, fast switching, excellent endurance, stability and scalability.
Perovskite employed memory devices were fabricated with a simple capacitor configuration (silicon-
metal–dielectric) consisting of Si/Au/CH3NH3PbX3 (X = I3, Br3 or Cl3) (MPI, MPB, MPC) hybrid
perovskite. The device exhibited remarkable unipolar and stable resistive switching behavior with
small on–off voltage of ˂ 2 V. In comparison to their inorganic counterparts, one noticeable advantage
of organic–inorganic hybrid perovskites lies in their facile and low temperature processability. Here,
we compare three different halide hybrid perovskite I/V in different temperature, variable voltage
Raman spectra, SEM, PXRD, UV-Visible etc. These devices can be used as resistive random access
memory (RRAM), based on the resistive switching (RS) effect originated from a sudden resistance
change, bistable state, and volatile properties. For device fabrication, first Si wafer was RCA cleaned
then 100 nm Au was coated on it by thermal evaporator. The perovskite solution (1M, DMSO solvent)
was dispensed onto the Au-Si substrate and spin-coated at 3000 RPM for 30 s in air, followed by
annealing at 80 °C for 10 min.
Figure: Optical Images of the devices (A) MPB, (B) MPC, (C) MPC. (D) I/V characteristic plot of three perovskites
(inset the photo of device attached with probe). (E) Chronoamperometry plot of device in different voltage.
Rh(II)-Catalyzed Denitrogenative Transannulation of N-Sulfonyl-1,2,3- triazolyl
Cyclohexadienones for the Synthesis of Benzofurans and Cyclopropa[cd]indole-
carbaldehydes
Geetanjali S. Sontakke, Kuntal Pal and Chandra M. R. Volla*
Abstract: A rhodium-catalyzed intramolecular denitrogenative transannulation of N-sulfonyl- 1,2,3-
triazole tethered cyclohexadienones has been achieved for the synthesis of benzofurans and
cyclopropa[cd]indole-carbaldehydes in an operationally simple procedure. Remarkably, the reaction
pathway is fully dependent on the linker heteroatom (O or N) present between the cyclohexadienone
unit and triazole moiety. In the case of O-linked triazoles, a cascade sequence consisting of
intramolecular cyclopropanation and rearrangement takes place leading to the formation of
benzofurans, while in case of N-linked triazoles, cyclopropa[cd]indole-carbaldehydes were isolated
exclusively.
Reference:
1. Sontakke, G. S.; Pal, K.; Volla, C. M. R. J. Org. Chem. 2019, 84, 12198−12208
A Systems Biology Approach to Understand Effect of Serum Level on
Mammalian Cell Cycle Progression Variability
Vinodhini Govindaraj, Atharva Karulkar, Subrot Sarma, Rahul Purwar and Sandip Kar
Abstract: Intercellular variability in cell cycle commitment and progression is often observed both
for normal and cancerous cell-types. Recent studies1 at the single cell level to quantify the cell cycle
timing variability revealed insightful information’s. However, the origin and nature of such variability
still remain to be poorly understood. Herein, we aim to unravel the effect of serum concentration
dependency of the intercellular cell cycle and phase timing variability’s using Fluorescent
Ubiquitination-based Cell Cycle Indicator (FUCCI)2 in two cancer cell lines of completely different
origin. Our study demonstrates that changing the serum concentration from low to high alters the
mean cell cycle and phase durations marginally, but significantly affects the variances observed for
different phase durations. Interestingly, the cell cycle period found to be preferentially correlating
with either G1 or S/G2/M phase durations depending on the relative ratio of the variances observed
for the G1 and S/G2/M phases under low or high serum concentration, respectively, for both the cell-
types. Additional statistical analysis shows that the slow cycling cellular population under different
regime of serum concentration governs the above mentioned variability. Our proposed minimalistic
cell cycle network model rationalizes our experimental observations, and predicts how to modify the
variances, and hence the correlation pattern of the cell cycle and phase timings in a serum dependent
manner more systematically.
References:
1. Sandler O, Mizrahi SP, Weiss N, Agam O, Simon I, & Balaban NQ. 2015. Nature, 519:
468-472.
2. Sakaue-Sawano A, Kurokawa H, Morimura T, Hanyu A, Hama H, Osawa H, Kashiwagi S,
Fukami K, Miyata T, Miyoshi H, Imamura T, Ogawa M, Masai H & Miyawaki A 2008.Cell
132:487–498
PdII, and PtII Assisted Tandem P−C Bond Breaking and P−N Bond Formation
Reactions from an Amide Functionalized Bisphosphine: Synthesis, Mechanistic,
and Structural Studies
Harish S. Kunchur and Maravanji S. Balakrishna*
Abstract: The replacement of substituents on the phosphorus center has significane in metal-
mediated synthesis and homogeneous catalysis. These replacements would employ metathesis-active
ligands, that can show non-innocent behavior 1, 2 when coordinated to transition metals.3 In this regard,
we synthesized new bisphosphine ligand 1, having amide group (CONH) as additional binding
functionality. The bisphosphine 1 shows interesting coordination modes (κ2-P,P or κ3-P,N,P) upon
treatment with transition metals. Treatment of 1 with [Pd(COD)Cl2] in 1:1 molar ratio afforded κ2-
P,P complex 2 with benzene as by-product, which is formed by tandem P–C bond breaking and P–N
bond formation in the ligand framework, similar reaction in the presence of a base yielded a PNP
pincer complex 3. Further, bisphosphine 1 on treatment with [Pd(η3-C3H5)Cl]2 in 2:1 molar ratio
afforded PNP pincer complex 3 with allyl chloride as by-product. In contrast, 1:1 reaction of 1 with
[Pd(η3-C3H5)Cl]2 afforded dinuclear complex 4. Unlike reactions with palladium, the bisphosphine 1
upon treatment with [Pt(COD)Cl2] afforded simple κ2-P,P complex 7, which on treatment with
LiHMDS gave κ2-P,P complex 8, formed by tandem P–C bond breaking, P–N bond formation and
phenyl migration from PPh2 to the metal center. Complex 7 upon refluxing in toluene or ligand 1 on
treatment with [Pt(COD)Cl2] in the presence of a base afforded platinum PNP pincer complex 9.
Mechanistic studies for the formation of complexes 2 and 8 were investigated using experimental as
well as by DFT calculations.
References:
1. Van der Vlugt, J. I. & Reek, J. N. H. Angew. Chem. Int. Ed. 2009, 48, 8832–8846.
2. Lyaskovskyy, V. & de Bruin, B. ACS Catal. 2012, 2, 270–279.
3. Lian, Z., Bhawal, B. N., Yu, P. & Morandi, B. Science, 2017, 356, 1059–1063.
Exploring the Enantioselectivity of Rh-Yanphos Catalyzed -methyl Styrene
Hydroformylation : Added Insights from Theory
Yuvraj Dangat and Raghavan B. Sunoj*
Abstract: Asymmetric hydroformylation (AHF) is an efficient methodology for producing chiral
aldehydes, which are important starting materials for pharmaceuticals and fine chemicals.1 Though
the AHF of monosubstituted alkenes, like styrene, is well established, it becomes challenging for
disubstituted alkene. Furthermore, the production of chiral aldehydes on an industrial scale is yet to
be achieved. In this regard, Zhang and coworkers2 have designed new hybrid phosphorus ligand and
successfully employed in -methyl styrene hydroformylation Scheme 1. Density functional theory
calculations have been employed to explore the factors controlling the enantioselectivity of this
important process. The calculations suggest that the migratory insertion of alkene is an
enantioselective step and the noncovalent interactions (mainly CH···) between substrate and
catalyst governs the enantio-selectivity.
Scheme: -methyl styrene.
References:
1. Franke, R.; Selent, D.; Borner, A. Chem. Rev. 2012, 112, 5675−5732.
2. You, C.; Li, S,; Li, X.;
Lan, J.;
Yang, Y.;
Chung, L. W.;
Lv, H.;
Zhang, X. J. Am. Chem.
Soc. 2018, 140, 4977−4981.
CHORh(acac)(CO)2(0.05mol%), L (0.15 mol%)
CO/H2 =2.5/2.5 bar, toluene, 80 oc, 90h, S/C=2000
TON=1720S1 PS
10 mmol, 1.18 g
1.25 g
84% yield, 87% ee
PAr2
N P
O
O
Bn
Ar = 3,5 tBu-C6H3
L=
Influence of Counter-Anion on the Zero Field Splitting of Tetrahedral Co(II)
Thiourea Complexes
Shalini Tripathi, Shefali Vaidya, Kamal Uddin Ansari, Naushad Ahmed, Eric Rivière, Lena
Spillecke, Changhyun Koo, Rüdiger Klingeler, Talal Mallah, Gopalan Rajaraman
and Maheswaran Shanmugam
Abstract: Four mononuclear Co(II) complexes with pseudo-tetrahedral geometry were isolated with
different counter anions; their structure solution reveals the molecular formula as [Co(L1)4]X2
(where L1 = thiourea (NH2-CS-NH2), X= NO3 (1), Br (2), I (3)) and [Co(L1)4](SiF6) (4)). The
detailed analysis of dc magnetic data reveals a zero-field splitting (ZFS; D) with the MS = ±3/2 as
the ground levels (D < 0) for the four complexes. The magnitude of the ZFS parameter is larger, in
absolute value, for 1 (D = -61.7 cm-1) than the other three complexes (-9.07 cm-1, -8.43 cm-1 and -
12.2 cm-1 for 2, 3 and 4 respectively). The sign of D for 1, 2 and 4 was unambiguously determined
by X-band EPR spectroscopy of the diluted samples (10 %) at 5 K. For 3, the sign of D naturally
endorsed from the frequency dependent out-of-phase signal
external dc magnetic field. It was further unequivocally confirmed by HF-EPR (70 – 600 GHz)
experiments performed on a representative pure polycrystalline 3 that gave a value of -5.1(1) cm-1.
Further, the drastic change in Spin Hamiltonian (SH) parameters and their related relaxation dynamics
phenomenon were rationalized using ab initio CASSCF/NEVPT2 calculations. Calculations disclose
that the structural distortion observed in 2-4 (due to the various anions in the crystal lattice) leads to
a non-favourable overlap between the π orbital of Co(II) and the π* orbital of the sulfur atom that
reduces the overall |D| value in these complexes compared to 1. The present study demonstrates that
not only the first but also the second coordination sphere significantly influences the magnitude of
the ZFS parameters. Particularly reduction of D up to ~90% has been witnessed (in 2-4 compared to
1) upon varying simply the counter-anions and offering a viable approach to modulate ZFS in
transition metal-containing SMMs.
Synthesis of Methyleugenol and Estargol Induced DNA Damages to Study
Translesion DNA Synthesis
Priyanka U. Deshmukh and Pradeep Kumar P. I.
Abstract: DNA damage is a well-established event responsible for carcinogenesis. DNA damaging
agents mainly cause modification at the nucleobases and disturb the W-C base pairing, which can
hamper DNA replication process by stalling replication fork. The fork can be rescued by translesion
synthesis (TLS), which is a DNA damage tolerance pathway. Methyleugenol (ME) and Estragole
(EG) are secondary metabolites found in herbs and spices (e.g. basil, pimento). It is known to form
N2 -dG DNA and N6-dA DNA adducts,1,2 which are responsible for carcinogenic activity in rat and
mouse. Herein, we report the synthesis of N2-ME-2’-dG adduct, N2 -EG-2'-dG, and N6 -ME-2'-dA
for their incorporation into DNAs.The damaged DNAs were synthesized using by solid phase
synthesis. Primer extension studies with Klenow fragment exo- (KF-)3, showed that incorporation of
correct base across modified dG with negligible extension. Further, we plan to carryout functional
and structural studies using human TLS polymerases Pol and Pol .
References:
1. McCulloch, S. D.; Kunkel, T. A. Cell Res. 2008, 18, 148-161.
2. Glatt. H. R. and Mienl. W.; K. Herrmann, W. Engst, S. Florian, A. Lampen. Toxicol. Res.
2016, 5, 808-818.
3. Pratibha P. Ghodke, S. Harikrishna, and P. I. Pradeepkumar. J. Org. Chem., 2015, 80, 2128-
2138.
Excess Electron Interactions with Solvated GC Base Pair: QM/MM Study
Ranga Santosh, Achintya KumarDutta
Abstract: We have investigated the effect of aqueous environment on the electron attachment process
to solvated Guanine-Cytosine (GC) base-pair. Since it happens in the ultrafast scale, the response of
the solvent (water) is important to understand the mechanism of electron attachment. In most of the
available implicit solvation models, solvent is treated as a structureless and with some dielectric
properties. Indeed, electron attachment through charge dipole interactions needs explicit environment
of solvent molecules which enhances the rate of electron attachment. To imitate the real life
environment and also to achieve the qualitative accuracy of experimental values of thermodynamic
properties, one has to treat the solvent explicitly which stabilizes the solute environment via hydrogen
bonding.
Our QM/MM results shows that the nuclear degrees of freedom of both water and GC base pair is
important to understand the electron transfer mechanism. The initial electron attached state is
localized on the water, and the GC bound anionic states appears as an excited state of the water-bound
ground state of the GC anion. The system undergoes a rapid reorganization of geometry following
the electron attachment, and the excess electron is localized around the cytosine in the GC base pair
within 5 fs, which is in contradiction with the previously reported DFT results. Our study shows that
the water molecules plays a cruscial role in stabilizing the anionic state by the extended hydrogen-
bonding network and enhances the rate of radiation damage in biological systems.
Figure: a) Transformation of water bound to the valence bound b) Potential Energy curve for the GC micro-solvated
base pair.
References
1) J. Phys. Chem. A2008,112,6217-6226.
2) J. Phys. Chem. B 2008,112,5189-5198.
3) Phys. Rev. Lett.2011, 106, 238108.
Stereoselective synthesis of tetrahydrocyclohepta[b]indole derivatives by
cascade radical cyclization of 3-propargylated-2-alkenyl indoles
Sanyog Kumari, Santosh J. Gharpure*
Abstract: Cyclohepta[b]indoles are privileged scaffolds owing to their presence in various bioactive
molecules and pharmacophores.1-2 Synthesis of these scaffolds has been achieved by metal mediated
reactions. Based on our ongoing effort for the synthesis of heterocycles using radical cyclization3-5
we have developed an efficient 6-exo-trig radical cyclization-cyclopropanation-ring expansion
cascade of 3-propargyl-2-alkenyl indole for the rapid synthesis of cyclohepta[b]indole in a highly
diastereoselective manner. Using the developed protocol various substituted cyclohepta[b]indole
derivatives has been synthesized in good yield with excellent diastereoselectivity.
References:
1. Cai, L.; Zhang, K.; Kwon, O. J. Am. Chem. Soc. 2016, 138, 3298.
2. Gritsch, P. J.; Stempel, E.; Gaich, T. Org. Lett. 2013, 15, 5472.
3. Gharpure, S. J.; Niranjana, P.; Porwal, Suheel K. Org. Lett. 2012, 14, 5476.
4. Gharpure, S. J.; Shelke, Y. G. Org. Lett. 2017, 19, 5022.
5. Gharpure, S. J.; Padmaja; Prasath, V,; Shelke, Y. G. Org. Lett. 2019, 21, 223.
A Dressed Coupled Cluster Theory for Molecular Energetics: Hydrogen-Bonded
& Strongly Correlated Systems
Anish Chakraborty, Rahul Maitra
Abstract: Non-covalent forces are ubiquitous in nature. The existing ab-initio theories often require
large basis set and high computational scaling to account for the same in a qualitatively correct
manner. This often restricts the applicability of these methods to small sized systems. In order to
circumvent this problem, I shall propose a dual exponential Ansatz based recursive similarity
transformed Coupled Cluster methodology, which accurately captures non-covalent interactions in
an affordable manner. The superior accuracy of the proposed method is ensured by the inclusion of
high rank correlation effects and a balanced treatment of screened Coulomb interactions. Our method
strikes the right balance between computational cost and accuracy, and thus promises to be a black-
box electronic structure tool in near future. We shall demonstrate the efficacy of the formulation with
a number of numerical examples on difficult systems with arbitrarily complex electronic
configurations. Further, I shall show a road-map within the framework of our theory to handle
strongly correlated molecular systems.
Redox Assisted Oxidative C-C Cleavage in Diruthenium
Complexes of 2,2'-Pyridil
Farheen Fatima Khan; G. K. Lahiri*
Abstract: Cleaveage of C-C bond has remained as a significant research domain due to its inevitable
implications in utilization of biomass during fuel production, in biomimicry, in waste management
for breaking down organic contaminants, etc.1 Low valent transition metal complexes have been
widely explored in this regard due to their ability to back donate electron density into the anti-bonding
orbitals of C-C bonds. On similar lines, our recent work exploited 2,2'-Pyridil and its analogue
(N1,N2-diphenyl-1,2-di(pyridin-2-yl)ethane-1,2-diimine) in diruthenium frameworks and
intriguingly varying responses were observed for the two on exposure to atmospheric oxygen.2 The
observations were further scrutinized and established by experiments and theoretical calculations
which extended interesting insights into redox mediated
oxidative cleavage of C-C bond.
References
1. C. J. Allpress, L. M. Berreau, Coord. Chem. Rev., 2013, 257, 3005-3029.
2. F. F. Khan, S. Sobottaka, B. Sarkar and G. K. Lahiri, Chem. Eur. J., 2019, 00
Solvent Mediated Relaxation Dynamics of Core-Shell Au-SiO2 Nanoparticles
Hemen Gogoi, Bala Gopal Maddala, Anindya Datta
Abstract: The inherent plasmonic property of nanosized gold particles makes it useful for various
applications ranging from photovoltaics to photothermal therapy.1 The crucial heat dissipation
dynamics of these nanostructures can be effectively probed with the help of transient absorption
spectroscopy. This technique helps us to understand the different pathways involved in the relaxation
dynamics of excited Au-SiO2 core-shell nanoparticles.2 Initially gold nanoparticles are synthesized
by reducing the gold precursor and then coated with silica by using tetraethyl orthosilicate (TEOS) to
enhance its stability.3 Synthesized nanoparticles were dispersed in solvents with different thermal
conductivities. By exciting the solutions with a strong laser pulse, the evolution of the excited state
dynamics in different surrounding environment has been monitored. The electron-phonon relaxation
time of Au-SiO2 nanoparticles has been found to be increased with decrease in thermal conductivity
of the solvent while the phonon-phonon relaxation time remains unaffected.
References:
1. Carattino, A.; Caldarola, M.; Orrit, M. Nano Lett.2018, 18, 874.
2. Mohamed, M. B.; Ahmadi, T. S.; Link, S.; Braun, M.; El-Sayed, M. A. Chem. Phys.
3. Lett.2001, 343, 55.
4. Fernández-López, C.; Mateo-Mateo, C.; Álvarez-Puebla, R. A.; Pérez-Juste, J.; Pastoriza
5. Santos, I.; Liz-Marzán, L. M. Langmuir2009, 25, 13894.
Facile Synthesis of Fused Core-Modified Sapphyrins
Prosenjit Isar and M. Ravikanth*
Abstract: Sapphyrins1are the oldest memberof expanded porphyrin family whichare 22π aromatic
pentapyrrolic systems. Sapphyrins can be used as MRI contrasting agents,multimetallic chelates for
catalysis, receptor for anions,models for aromaticity and photosensitizers in photodynamic therapy.
Core modification by replacing one or two pyrroles in sapphyrins with other five-membered
heterocycles such as thiophene, furan, selenophene, benzene2 etc alters the photophysical and
chemical properties significantly. The fused benzodipyrrole-derived sapphyrins have stronger effect
on the electronic properties to that of π-extended sapphyrin analogues because of the rigidity of the
bipyrrole unit. However, the available synthetic routes are long and requires not so easily accessible
precursors. Herein, we are presenting a facile and shortest synthetic routes for oxabenzosapphyrins
and p-benzibenzosapphyrins (Chart) using readily available precursors. The structural, spectral and
electrochemical studies of these macrocycles show interesting properties.
Chart
References:
1. Chatterjee, T.; Srinivasan, A.; Ravikanth, M.; Chandrashekar, T. K. Chem. Rev.2017, 117 (4),
3329–3376.
2. Sengupta, R.; Thorat, K. G.; Ravikanth, M. J. Org. Chem.2018, 83 (19), 11794–11803.
Wet and dry internal friction can be measured with the Jarzynski equality
R. Kailasham, Rajarshi Chakrabarti, J. Ravi Prakash
Abstract: The existence of two types of internal friction [1]—wet and dry—is revisited, and a simple
protocol is proposed for distinguishing between the two types and extracting the appropriate internal
friction coefficient. The scheme requires repeatedly stretching the polymer molecule, and measuring
the average work dissipated in the process by applying the Jarzynski equality. The internal friction
coefficient [2] is then estimated from the average dissipated work in the hypothetical limit of zero
solvent viscosity. The validity of the protocol is established through analytical calculations on a one-
dimensional Hookean spring-dashpot, and Brownian dynamics simulations of a single-mode
nonlinear spring-dashpot model for a polymer which incorporates fluctuating hydrodynamic
interactions [3]. The protocol is then used to analyze stretching simulations on a single polymer chain
with cohesive interactions between the beads, and the internal friction due to such intra-chain
interactions is shown to be of the wet type. Well-established single-molecule manipulation
techniques, such as optical tweezer-based pulling, can be used to implement the suggested protocol
experimentally.
References:
[1] A. Soranno, B. Buchli, D. Nettels, R. R. Cheng, S. Muller-Spath, S. H. Pfeil, A. Hoffmann, E. A.
Lipman, D. E. Makarov, B. Schuler, Proc. Natl. Acad. Sci. U. S. A. 109, 17800 (2012).
[2] N. Samanta and R. Chakrabarti, Phys. A 450, 165 (2016).
[3] R. Kailasham, R. Chakrabarti, and J. R. Prakash, J. Chem. Phys. 149, 094903 (2018).
Iron(III)/O2-Mediated Regioselective Oxidative Cleavage of
1-Arylbutadienes to Cinnamaldehydes
Amit Bhowmik and Rodney A. Fernandes*
Abstract: Cinnamaldehyde have various synthetic applications and its numerous derivatives are
commercially useful in food, cosmetic industries and also show various biological activities.1,2 Due to
their wide applications in organic synthesis as well as in industrial use, several methodologies have
been developed so far for their synthesis.3 However, eco-friendly and efficient methods for the
preparation of cinnamaldehydes still remains a challenge for organic chemists. Herein,
Fe2(SO4)3.nH2O/O2 has been used for oxidative regioselective cleavage of 1-arylbutadienes
tocinnamadlehydeswith excellent yields.4 The key features of this methodology are, it offers excellent
regioselectivity, environmentally friendly conditions, functional group tolerant, simple and mild
reaction conditions. The present oxidative cleavage method was employed in the synthesis of bioactive
substituted sinapaldehydes5 and the trienone curcuminoids.6 The details of this work will be presented.
References
1. Fang, J. M.; Chen, S. A.; Cheng, Y. S. J. Agric. Food Chem. 1989, 37, 744.
2. Ishida, S.; Matsuda, A.; Kawamura, Y.; Yamanaka, K. Chemotherapy 1960, 8, 157.
3. Nordqvist, A.; Björkelid, C.; Andaloussi, M.; Jansson, A. M.; Mowbray, S.; Karlen, A.;
Larhed, M. J. Org. Chem. 2011, 76, 8986.
4. Bhowmik, A.; Fernandes, R. A. Manuscriptin preparation.
5. Zhao,Y.; Hao, X.; Lu, W.; Cai, J.; Yu, H.; Sevénet, T.; Guéritte, F. J. Nat. Prod. 2002, 65,
902.
6. Chuprajob, T.; Changtam, C.; Chokchaisiri, R.; Chunglok, W.; Sornkaew, N.; Suksamrarn,
A. Bioorg. Med. Chem. Lett. 2014, 24, 2839.
Biophysical Insights into the Spatially Organized Cell Envelope of
Mycobacterium smegmatis.
Pranav Adhyapak, Shobhna Kapoor
Abstract: Mycobacterium tuberculosis, the etiological agent of tuberculosis, possesses an atypical
cell envelope comprising of peptidoglycan-arabinogalactan complex with covalently bound mycolic
acids (C60-C90) and lipids accounting for 40% of its dry weight. The cell envelope lipids are known
to form an impermeable barrier against an array of antimicrobial drugs, aiding mycobacterial survival
and resistance. The decisive role of each of the spatially organized lipid component of mycobacterial
cell envelope is not yet fully understood. We aimed to isolate and study distinct components of
mycobacterial envelope from Mycobacterium smegmatis mc2155 using steady state fluorescence
spectroscopy, atomic force microscopy, infra-red spectroscopy, and confocal microscopy to gain an
insight into phase state behavior and nanomechanical properties of these lipids. These studies will
pave way to design an effective mimic of mycobacterial membrane that can be used as a model
membrane to test membrane perturbing activity of number of bioactive compounds.
Reference:
1. Ritu Bansal-Mutalik, Mycobacterial outer membrane is a lipid bilayer and the inner
membrane is unusually rich in diacyl phosphatidylinositol dimannosides, PNAS 111 (2014)
4958-4963.
2. B. Zuber, M. Chami, C. Houssin, J. Dubochet, G. Griffiths, M. Daffe, Direct visualization of
the outer membrane of mycobacteria and corynebacteria in their native state, J. Bacteriol. 190
(2008) 5672–5680.
Synthesis of Hole Transport Materials Using Pentiptycene Core as the Building Block
Ratika Maini and Anil Kumar*
Abstract: Pentiptycene comes under the class of iptycene family. The propeller structure, thermal
and structural stability1, high glass transition temperature of the molecule has gained popularity in
widespread applications like TNT sensor2, molecular brakes, supramolecular chemistry. The
presentation talks about its candidature as transport material in Photovoltaic applications.
Pentiptycene based donor-bridge-donor derivatives (P(a), P(b), P(c), P(d) have been synthesized. The
optical and the electrochemical behavior gives HOMO and LUMO level of the compounds which
opens up the possibility of pentiptycene based compounds as an application in Hole transport layer.
References:
(1) Yang, J.-S.; Swager, T. M. Journal of the American Chemical Society1998, 120, 11864.
(2) Yang, J.-S.; Lin, C.-S.; Hwang, C.-Y. Organic Letters2001, 3, 889.
Carrageenan Beads Incorporated Fluorophoric Calix[4]arene Conjugate for
Selective, Efficient, Reversible and Fingerprint Detection of Trinitrophenol
Ashiv Narula, Aekta Upadhyay and Chebrolu Pulla Rao
Abstract: A fluorescent naphthalimide conjugate of calix[4]arene (L1) has been demonstrated for
selective and efficient detection of trinitrophenol (TNP) among nine other nitroaromatic compounds
(NACs) using the absorption and fluorescence spectroscopy. The minimum detection limit (LOD)
was found to be 29 nM, which is the lowest reported so far by any conjugate of calixarene and the
Stern-Volmer constant is also as high as (3.3±0.4) x 105 M-1. Both the SEM and TEM microscopy
reveals pores network of the probe L1 were filled with fibril structures upon addition of TNP. The
probe L1 is coated onto a whatman filter paper and utilised for fingerprint sensing of TNP. The 1H-
NMR titration and the studies carried out using the control molecule ‘C1’ (deprived of calixarene)
supports the necessity of both the naphthalimide moiety and the calixarene derivative. The probe L1
is incorporated into the carrageenan beads (L1@Cb) for the reversible sensing of TNP. The solid state
detection of TNP has also been demonstrated using the lyophilized L1@Cb bead powder using the
fluorescence microscope.
Selective & Efficient
But Not-reversible
Method-I
Method-II
Probe incorporated
Carrageenan beads
KCl TNP KCl
Reversible
Fluorescent
beads
Fluorescence
quenches
Design and Synthesis of Highly Dense Homocubane Derivatives
Sohan Lal, Neeraj Kumbhakarna, Arindrajit Chowdhury, Irishi N. N. Namboothiria*
Abstract: Polycyclic cage compounds have received tremendous attention in diverse aspects of
science such as High Energy Density Materials (HEDMs), catalysis, pharmaceuticals,natural product
synthesis and in medicinal chemistry.1-5 These diverse applications are due to their distinctive
properties, such as severely strained molecular structures, rigidity and lipophilic nature. Cage
compounds are a new class of potential HEDMs with severely strained molecular structures. This
study demonstrates the synthesis, thermodynamic characterization and energetic properties of highly
dense homocubane-based compounds, which have been synthesized, for the first time in good to
excellent yields. These compounds have higher HOF and higher energy densities than traditional
hydrocarbon fuels. Gas phase densities, gas phase HOF and their geometry were calculated with
B3LYP/6-31++G(d,p). In general the calculated HOF, densities (ρ) and density specific impulse
(ρIsp,vac) of these compounds turn out to be extremely high which is typical of high-nitrogen and
halogenated compounds. Ballistic properties such as vacuum specific impulse (Isp) and density
vacuum specific impulse (ρIsp) were calculated using the NASA CEA (Chemical Equilibrium and
Applications) utility. The compounds can be used as standalone fuels in liquid bipropellant systems,
or as additives in liquid and solid propellants.
References
1. Agrawal, J. P. Prog. Energ. Comb. Sci., 1998, 24, 1.
2. Eaton, P. E.; Cole, T. W. J. Am. Chem. Soc, 1964, 86, 3157.
3. Lal, S.; Rajkumar, S.; Tare, A.; Rashmi, S.; Chowdhury, A.; Namboothiri, I. N. N. Chem.
Asian J. 2014, 9, 3533.
4. Lal, S.; Mallick, M.; Rajkumar, S.; Oommen, O. P.; Reshmi, S.; Kumbhakarna, N.;
Chowdhury, A.; Namboothiri, I. N. N. J. Mater. Chem. A. 2015, 3, 22118.
5. Mallick, L.; Lal, S.; Reshmi, S.; Namboothiri, I. N. N.; Chowdhury, A.; Kumbhakarna, N.
New J. Chem. 2017, 41, 920.