DUQUESNE UNIVERSITY American Chemical Society Student Affiliation TWENTY THIRD ACS “IN-MINIATURE” SYMPOSIUM April 18, 2009 Chemistry and Biochemistry Department Bayer School of Natural and Environmental Sciences Duquesne University Pittsburgh, PA 15282 Allegheny College California University of Pennsylvania Carlow University Chatham College Duquesne University Geneva College Grove City College La Roche College Indiana University of Pennsylvania University of Pittsburgh at Johnstown Saint Francis University Seton Hill University St. Vincent College Thiel College University of Pittsburgh Slippery Rock University Washington & Jefferson College Waynesburg College Westminster College Wheeling Jesuit University Youngstown State University
Transcript
DUQUESNE UNIVERSITY American Chemical Society Student Affiliation
TWENTY THIRD ACS “IN-MINIATURE” SYMPOSIUM
April 18, 2009
Chemistry and Biochemistry Department Bayer School of Natural and Environmental Sciences
Duquesne University Pittsburgh, PA 15282
Allegheny College
California University of Pennsylvania
Carlow University
Chatham College
Duquesne University
Geneva College
Grove City College
La Roche College
Indiana University of Pennsylvania
University of Pittsburgh at Johnstown
Saint Francis University
Seton Hill University
St. Vincent College
Thiel College
University of Pittsburgh
Slippery Rock University
Washington & Jefferson College
Waynesburg College
Westminster College
Wheeling Jesuit University
Youngstown State University
2009 ACS In‐Miniature Symposium
Duquesne ACS Affiliates: Kailey Ruszkowski, President; Matt Taylor, President‐Elect; Ashley Biernesser, Vice President‐Elect; Sean Noonan, Vice President‐Elect; Jessica Rabuck, Treasurer‐Elect; Jonathon Gibbons, Secretary‐Elect. April 18, 2009 Dear Faculty Advisors and Students, This event represents the twenty‐third Pittsburgh Section Student Affiliate Meeting. Undergraduate research is a rewarding experience, which impacts your future career in chemistry and the chemical sciences. The Pittsburgh Section and all of its members are proud of the effort that you and your mentors have put forth to make our region exceptional strong. In the past, over two hundred professionals have contributed to this special effort. In fact, we have over 50 participants this year, which sets a new record! Many of the previous contributors have distinguished themselves in the medical, chemical, dental, educational, and other professions, and many have become leaders in the American Chemical Society. To all of these individuals, and to you, the Section is indebted. We hope that this meeting will be a successful and rewarding experience. Sincerely Yours, Sincerely, Sincerely,
Jeffrey D. Evanseck Paul G. Johnson ACS Student Affiliate Advisor ACS Student Affiliate Advisor Professor, Chemistry and Biochemistry Assistant Professor, Chemistry and Biochemistry Lauritis Chair of Teaching and Technology
IN MEMORY OF
THEODORE J. WEISMANN (1930‐2007)
ACS Student Affiliate Advisor Duquesne University
Department of Chemistry and Biochemistry
His life was devoted to his profession and his students. He possessed the unique ability of recognizing the special talents in young men and women, and he encouraged them to pursue
careers in chemistry.
We cannot always build the future of our youth, but we can build our youth for the future ‐‐ FDR
Lunch (College Hall 103) 1:00 – 2:00 pm (Lunch provided – including vegetarian selection) 1:15 – 1:45 Dr. Karl W. Haider, Innovation Manager, New Technologies Group
Everyone (faculty, students and visitors) must register (free of charge), and students presenting posters must additionally submit their abstracts at the same site given above.
Questions? Contact the Duquesne Student Affiliates [email protected]
“Artificial Intelligence Tutoring Software for General Chemistry”
2008 Award Winners
Kayce Tomcho Slippery Rock University
Kimberly A. Schrock St. Francis University
Caitlin Williamson Indiana University
Carlene Pasipanki Seton Hill University
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Participants for the 2009 ACS Student Affiliates ACS in‐Miniature Symposium Dr. Jennifer A. Aitken Duquesne University [email protected] (412) 396‐1670 Caitlin Basile (Poster 16) Saint Francis University [email protected] (814) 472‐3910 Lacey J. Behe University of Pittsburgh at Johnstown [email protected] (814) 327‐0852 Brittany Black Slippery Rock University [email protected] 724‐630‐4133 Keri Biedka Westminster College [email protected] (724) 355‐9466 Ashley Biernesser (Poster 18) Duquesne University [email protected] 724 799 9266 Dr. Paul J. Birckbichler (Poster 19) Slippery Rock University [email protected] 724‐738‐2494 Brittany Bivens (Poster 4) Westminster College [email protected] (814) 573‐3924 Dr. Helen Boylan Westminster College [email protected] (724) 946‐6293
Tiffany A. Bumbarger (Poster 7) University of Pittsburgh at Johnstown [email protected] (814)233‐3228 Dr. Rose A. Clark Saint Francis University [email protected] (814) 472‐3910 Kerry Connolly (Poster 2) Sto‐Rox High School [email protected] 412‐771‐3213 x1243 Will Eckenhoff (Poster 8) Duquesne University [email protected] 610‐306‐1547 Dr. Jeffrey D. Evanseck Duquesne University [email protected] (412) 396‐6337 Dr. Ellen S. Gawalt Duquesne University [email protected] 412‐396‐4709 Jonathon Gibbons (Poster 22) Duquesne University [email protected] (412) 427‐1777 Dr. Karl W. Haider New Technologies Group Bayer Material Science [email protected] 412‐777‐7897 Dr. Balazs Hargittai Saint Francis University [email protected] 814‐472‐2814
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Dr. Mark F. Harris Washington and Jefferson College [email protected] 724‐223‐6134 Heather J. Harteis (Poster 5) Saint Francis University [email protected] 814‐472‐2814 Justin Hileman (Poster 6) Indiana University of Pennsylvania [email protected] 727‐357‐4489 Kristin Johnson (Poster 14) Youngstown State University [email protected] 330‐941‐6192 Dr. Paul (PJ) Johnson Duquesne University [email protected] 412‐396‐6615 Miles Kaltenbach (Poster 15) Duquesne University [email protected] 724‐234‐7640 Emma Karey (Poster 10) Chatham University [email protected] 301 980 6549 Brooke Katzman Youngstown State University [email protected] 330‐727‐7390 James Z. Klingensmith Washington and Jefferson College [email protected] 724‐989‐6419
Erin Lawrence (Poster 19) Slippery Rock University [email protected] 7246510258 Dr. Michael S. Leonard Washington & Jefferson College [email protected] 724‐223‐6131 Beth Leverett (Poster 3) Indiana University of Pennsylvania [email protected] 518‐810‐2796 Michael Liebert Washington & Jefferson College [email protected] Phone: 412‐628‐1454 Casey G. Lipovsky Duquesne University Jennifer MacNeil Chatham University [email protected] (412) 365‐1216 Dr. Joseph MacNeil Chatham University [email protected] (412) 365‐1216 Dr. Jeffry D. Madura Duquesne University [email protected] (412) 396‐6341 Dr. Kerry McMahon Geneva College [email protected] 724‐847‐6722 Dr. Rita Mihailescu Duquesne University [email protected] (412) 396‐1430
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Christopher S. Naitza (Poster 9) University of Pittsburgh at Greensburg [email protected] 518‐330‐3692 Sean Noonan (Poster 20) Duquesne University [email protected] 412‐719‐5401 Dr. Peter Norris Youngstown State University pnorris@ ysu.edu (330) 941‐1553 Kristin Olejar (Poster 1) Sto‐Rox High School [email protected] (412)‐370‐4201 Dr. Kristina Pazehoski University of Pittsburgh at Greensburg [email protected] 724‐836‐9891 Dr. Tomislav Pintauer Duquesne University [email protected] (412) 396‐1626 Jessica Rabuck (Poster 21) Duquesne University [email protected] 814‐232‐0813 Jared Romeo Duquesne University [email protected] 724‐510‐6927 Jacob Rosenbaum (Poster 13) University of Pittsburgh at Johnstown [email protected] 814‐289‐3603
Ashley Ruozzo (Poster 12) Youngstown State University [email protected] (330) 942‐3745 Janelle Russell (Poster 12) Youngstown State University [email protected] (503) 381‐5621 Dr. Ronald See Indiana University of PA [email protected] 724‐357‐4489 Nicole Shamitko (Poster 11) Washington and Jefferson College [email protected] 412‐527‐3864 Dr. Omar W. Steward Chemistry and Biochemistry [email protected] 412 396 6338 Dr. Nina V. Stourman Youngstown State University [email protected] 330‐941‐7112 Mathew J. W. Taylor (Poster 17) Duquesne University [email protected] 724‐518‐4800 Dr. Richard Ulsh University of Pittsburgh at Johnstown [email protected] 814‐269‐2903 Benjamin Veres Washington & Jefferson College [email protected] 412‐266‐4587
2009 American Chemical Society in Miniature Poster Presentations 1
2009 American Chemical Society Student Affiliates, Duquesne University
Poster Number 1
Conformational Analysis using MOE software Kristin Olejar1, Jeffry D. Madura2.
1Sto-Rox High School
2Department of Chemistry and Biochemistry, Center for Computational Sciences, Duquesne University
Conformational analysis is a method used to explore the spatial arrangements of atoms in a molecule. Conformational analysis is commonly used to understand drug interactions and the binding of molecules. The conformational analysis of molecules through computer software allows students to visualize these types of interactions. A workbook is being constructed that is directed toward high school and undergraduate students and serves as a guide for some simple exercises in the Molecular Operating Environment (MOE) software. The exercises demonstrate how to perform a conformational analysis on molecules with various numbers of rotatable bonds. The workbook provides an understanding of what a conformational analysis is and gives users a simple set of directions for successfully completing a task on MOE.
Poster Number 2
Solution Study of Copper(II) Complexes Kerry L. Connolly1, William T. Eckenhoff2 and Tomislav
Pintauer2
1Sto-Rox High School
2Department of Chemistry and Biochemistry, Duquesne University
Copper(II) halide complexes with tetradentate nitrogen based ligands are commonly used as catalysts in transition metal mediated atom transfer radical addition and cyclization reactions. Structural features of these highly active complexes are still not fully understood. In particular, the role of halide anion coordination to copper(II) complexes is still very unclear. [CuII(TPMA)X][Y] complexes (TPMA= Tris(2-pyridylmethyl)amine, X= Cl, Br, Y= Cl, Br, BPh4, PF6 and ClO4) have been synthesized and characterized by UV-Visible spectroscopy in order to observe the effect of the counter-ion on absorbance. Molar absorbances were obtained through a differential concentration analysis using Beer’s Law. By measuring the rate of reaction, we can begin to understand what makes these complexes more or less active for ATRA.
Poster Number 3
Li2FeSnS4: Synthesis of a Quaternary Diamond-Like
Semiconductor Beth Leverett1, Jonathan W. Leske2, Jennifer Aitken2
Indiana University of Pennsylvania
2Department of Chemistry and Biochemistry, Duquesne University
Diamond-like semiconductors (DLS) have attracted increased attention for their potential applications in data storage, computing and optics. Due to their complexity, quaternary diamond-like compounds have yet to be explored to the same extent as their binary and ternary counterparts. Li2FeSnS4, a I2-II-IV-VI4 DLS, was synthesized using traditional high temperature solid state reactions. A comparison of the product's powder X-ray diffraction pattern with calculated patterns of known DLS structures indicated that Li2FeSnS4 crystallizes in space group Pn. Additionally, alkali polysulfide flux reactions were carried out to improve the phase purity of the product and obtain single crystals. Characterization of reaction products using X-ray diffraction, diffuse reflectance spectroscopy and thermal analysis will be presented.
Poster Number 4 Qualitative analysis and prospective quantification method for laser induced breakdown spectroscopy
Brittany Bivens,
Westminster College Laser induced breakdown spectroscopy (LIBS) utilizes an energetic laser pulse to ablate matter, forming a plasma which disassociates into atomic and ionic species that emit light. This light can used to qualitatively determine the composition of sample materials because each element emits radiation at characteristic wavelengths. LIBS was used to investigate the qualitative differences between the metal and resin of an aluminum can as well as the layers of several pharmaceuticals. By varying the number of laser pulses, it was possible to differentiate the layers of the samples based on peak intensity differences in the spectra at different depths. Attempts were also made to design a simple quantitative method for LIBS analysis. The use of peak ratios allowed for semi-quantitative analysis of different elements within these samples, but data analysis proved to be complex. Thus a simple method for quantitative analysis needs further development.
2009 American Chemical Society in Miniature Poster Presentations 2
2009 American Chemical Society Student Affiliates, Duquesne University
Poster Number 5
Role of Proline in the Formation of Biologically Active Regioisomers of alpha-Conotoxin
Heather J. Harteis, KaLynn M. Kline, Balazs Hargittai
Saint Francis University
Evaluation of the role of disulfide bridges plays an important part in the understanding the concept of protein folding. We are investigating how slight changes - the presence vs absence of the cyclic amino acid protein in a certain position of the peptide chain - in the sequence of small peptides influence their folding properties. The present studies focus on the folding of a group of small peptides found in Conus snails, alpha-conotoxins SI, SIA (found in Conus Striatus), and GI, GII (Conus Georgraphus) under two different oxidizing conditions. Each peptide has two disulfide bridges leading to three possible regioisomers, only one of which is found in nature. Our results indicate that peptides containing the cyclic amino acid proline had very high selectivity for the natural isomer, suggesting that this amino acid enforces a structural rigidity on the peptides.
Poster Number 6 Computational studies of N-H---O hydrogen bonds
in gas phase and solvents Justin A. Hileman, Ashley Swiderski and Dr. Ronald F.
See Indiana University of Pennsylvania
This study uses computational methods to investigate N-H…O hydrogen bonds. Hydrogen bonds are found in a wide variety of applications, and N-H…O hydrogen bonds are particularly relevant in biological systems. The complexes studied were imidazole…OS and imidazole…OCH2. These computational studies were carried out at the B3LYP/6-31G* level, which has been shown to accurately reproduce experimental hydrogen bond energies in other complexes. The results show hydrogen bond energies of 20.0 kJ/mol for the imidazole…OS system, and 17.6 kJ/mol for the imidazole…OCH2 system. Work was also done to detail the effect of solvent on hydrogen bond energy, using the SM8 computational solvation process. In each case, hydrogen bond energies were reduced by solvation, with the magnitude of the reduction being proportional to the reciprocal of the dielectric of the solvent. Implications of these results for specific biological systems will also be presented.
Poster Number 7
How fast will an electron travel? Model complexes
to study the kinetics of proton-coupled electron transfer on self-assembled monolayers
Elisabeth Bell-Loncella, Tiffany A Bumbarger,
University of Pittsburgh at Johnstown
There is considerable interest in designing model complexes that mimic the proton-coupled electron transfer (PCET) reactions found in biological systems such as oxidative phosphorylation in mitochondria and photosynthetic processes in chloroplasts. Ruthenium polypyridyl complexes serve as a platform for PCET studies. In previous work a series of ruthenium complexes were shown to display PCET. The next logical step is to understand the kinetics of these reactions – that is how fast electron transfer takes place. One approach is by coupling the target complex to self assembled monolayers (SAM) on a gold electrode. Presently we are developing a synthetic methodology for the preparation of [Ru(trpy)(4-AMP)(dmgH2)]2+ (where trpy is terpyridine, 4-AMP is 4-aminomethyl pyridine and dmgH2 is dimethylglyoxime). This complex will be tethered to the SAM through the amine of the 4-AMP. Herein, in we present several preliminary strategies and the insights gained, along with a newly-proposed synthetic method that is showing promise.
Poster Number 8
Catalyst Regeneration and Structural Studies as a Means of Reducing Metal Concentration in Atom
Transfer Radical Addition (ATRA) Will Eckenhoff and Tomislav Pintauer
Department of Chemistry and Biochemistry, Duquesne
University The atom transfer radical addition (ATRA) is a versatile method for carbon-carbon bond formation, yielding highly functionalizable products. Historically, transition metal catalyzed ATRA has required a large amount of catalyst needed to achieve high yields of the target compound (typically 5-30 mol% relative to alkene). Copper halides have been shown to be highly effective catalysts in ATRA and considerably less toxic than other transition metals. Small amounts of AIBN, which acts to continuously regenerate the deactivator or copper(II) complex, allows the catalyst loading to be reduced to ppm levels in atmospheric conditions at 60oC. In a more energy efficient method, free radical initiator V-70 can be used at room temperature. In this method, unparalleled control of the reaction was observed with alkenes known to rapidly polymerize at elevated temperatures such as styrene, methyl acrylate, methyl methacrylate, and vinyl acetate with low catalyst loadings.
2009 American Chemical Society in Miniature Poster Presentations 3
2009 American Chemical Society Student Affiliates, Duquesne University
Poster Number 9
Cloning of the clock gene Christopher S. Naitza, Khristina O. Pazehoski,
University of Pittsburgh at Greensburg
Current research has indicated similar sequences, as well as functions, between Circadian Locomotor Output Cycles Kaput (CLOCK or KIAA0334) and Neuronal PAS Domain 2 (NPAS2 or MOP4) proteins. Regulation of circadian rhythm depends on both CLOCK and NPAS2 proteins. Neuronal transmitters such as Carbon Monoxide (CO) and Nitric Oxide (NO) regulate the DNA binding activities of NPAS2, a hemoprotein. This may be true for CLOCK. The objective is to clone the human clock gene into a bacterial expression vector. Success will allow for the purification of the CLOCK protein. Experiments may then be carried out on the pure protein to determine its heme binding ability. Required protocol consists of; PCR of the clock gene and the pET-14b expression vector, separation of PCR products by gel extraction and purification, restriction digest of excised PCR fragments, ligation, and the transformation of BL21 cells to later express the CLOCK protein.
Poster Number 10
Chelate-assisted cadmium uptake in hydroponic systems correlates with sunflower growing stages.
Emma Karey, Michelle Meighan, Nicole Persson, Joseph MacNeil,
University of Pittsburgh at Johnstown Using phytoremediation to remove heavy metals from brownfields is challenging because soil factors can limit metal mobility. EDTA, a common chelating agent, enhances metal ion mobility in soils. Our work has shown the efficacy with which sunflowers accumulate Cd(II) varies during a plant’s life cycle. Preliminary data suggest that growing and harvesting multiple sets of seedlings every few weeks could remove more metal from the soil than a single seasonal harvest after plants have matured. Lab work to refine and evaluate potential field applications required the manipulation of two variables: plant age and timing of EDTA introduction. Sunflowers were grown in a hydroponic model system of 30 ug/mL CdSO4 in 3-fold-molar EDTA-excess aqueous solutions. Cd(II) was introduced to plants of different ages, allowing us to map accumulation as a function of sunflower age. Young plants accumulate Cd(II) quickly, then enter a latent period, followed by another period of reduced accumulation.
Poster Number 11
Respiratory Hazards of the Mining Industry
Nicole Shamitko
Washington and Jefferson College Mining is one of the most important industries in the world. It provides a source of energy, metals, gems, and stone for our infrastructure. Every day, miners are faced with many different hazards. The purpose of this research is to discuss the respiratory hazards of the mining industry. Three extremely hazardous inhalants to miners are: coal dust, silica dust and diesel particulate matter. Coal dust is associated with coal workers pneumoconiosis, exposure to silica dust may cause silicosis, and diesel particulate matter is of concern because it is a possible carcinogen. Three different instruments that are necessary to limit or prevent exposure to these hazards will be discussed, including: the Personal Dust Monitor, a canopy air curtain and the EC Optical Monitor.
Poster Number 12 Design of affinity matrix with gluthathionylspermidine
Ashley Ruozzo, Janelle Russel, Nikita Goswami Youngstown State University
In most organisms, from bacteria to humans, low-molecular weight thiol - glutathione (GSH) plays important roles in the protection from a variety of harmful compounds. The unique feature of microorganism E. coli is the formation of the conjugate between glutathione and polyamine spermidine – glutathionylspermidine (G-Sp) by the enzyme glutathionylspermidine synthetase (GSS). We hypothesize that G-Sp can replace GSH in a variety of reactions and participate in some physiologically important processes in E. coli; therefore, the metabolism of G-Sp might serve as a target for potential drug discovery in the combat against pathogenic strains of E. coli and related pathogens such as Salmonella. Our main objective is the creation of affinity chromatography matrices with G-Sp molecules attached. G-Sp was synthesized enzymatically using GSS and purified using cation-exchange chromatography. It was then characterized by HPLC and mass spectrometry and coupled with epoxy-activated sepharose. The properties of the resulting matrix are under investigation.
2009 American Chemical Society in Miniature Poster Presentations 4
2009 American Chemical Society Student Affiliates, Duquesne University
Poster Number 13
Laboratory ranking of household oxidizers using spectroscopy
Jacob Rosenbaum, Richard Ulsh
University of Pittsburgh at Johnstown
This is a general chemistry experiment where we rank the strength (effectiveness) of various household oxidizers using commercially available Benedict’s reagent as a redox indicator. Benedict’s is the classical reagent to test for the presence of the reducing sugar, glucose, in urine. In this capacity, the blue aquated copper(II) ion is reduced to a red copper(I) oxide precipitate at elevated temperatures. Benedict’s reagent is employed here in the reverse direction as a reducing agent. The copper(II) ion in Benedict’s is first reduced completely to the copper (I) state by the stoichiometric addition of the strong reducing agent ascorbic acid, accompanied by a color change from dark blue to a red precipitate. This becomes the reagent for the ranking of oxidizing agents.
Poster Number 14
One-Pot Approach to 1,2,3-Triazoles Using in Situ Generated Azide Anion
Kristin Johnson, Brooke Katzman, Daniel Temelkoff and Peter Norris
Youngstown State University
Alkyl and acyl azides are essential precursors in organic and medicinal chemistry yet they are notoriously difficult to work with because many of them have a habit of detonating when isolated in the pure form. We have developed a new approach to both alkyl and acyl azides, using microwave heating to shorten reaction times, in which reaction progress is monitored by infrared spectroscopy. Being able to follow azide generation in situ allows us to track the formation of ionic and covalent azide species conveniently, and then react the alkyl or acyl azide further to produce materials such as 1,2,3-triazoles in one reaction flask with minimal risk.
Poster Number 15
Dibenzoylmethane Complexes of Cobalt: Nature of the Cobalt Complexes and Diazoaromatic Bases vs.
the Structures Miles V. Kaltenbach, Ashley B. Biernesser, Matthew J. Taylor, Katie J. Hovan, Jordan Verplank, and Omar W.
Steward
Department of Chemistry and Biochemistry, Duquesne University
The structures of the dibenzoylmethane complexes vary as a function of the starting cobalt(II) complexes and the nitrogenous bases when prepared in a 50 %, by volume, methanol/methylene chloride solution. In this solvent system, ligands scramble and form the most insoluble complex on slow evaporation of the solvent. Cobalt(II) acetylacetonate·4-hydrate and cobalt(II) acetate·4-hydrate have yielded different products. Also, the structures of the products vary with the molecular geometries of the diazoaromatic bases; steric hindrance plays a major role. Two types of supramolecular polymers are formed: coordination polymers via cobalt and hydrogen bonded polymers via nitrogen-oxygen and/or oxygen-oxygen hydrogen bonds. The backbone of the polymer formed using the base quinoxaline approximates the form of a sine wave. In two cases, cobalt(III) secondary products have been isolated which result from air oxidation. We are indebted to the Dreyfus Foundation for the support of this project.
Poster Number 16 Cytochrome c electrochemistry: Determining the
effects of self-assembeled monolayer composition of the protein formal potential and electron transfer
rate. Caitlin Basile, David Kirby, Colin Trout, Kimberly
Schrock, Rose A .Clark
Department of Chemistry, Saint Francis University
Cytochrome c (cytc) is a redox protein that can be found in the mitochondria of all living organisms. Because of its biological importance in creating cellular energy, as well as its small size, availability, and ease of handling, cytc has been studied extensively. Based on literature research, the redox behavior of cytc with modified electrode surfaces is complex. The present research probes the redox properties of cytc adsorbed onto mixed self-assembled monolayer (SAM)/gold electrodes. Electron transfer rate constants are determined using cyclic voltammetry and Marcus Theory. It has been found that the electron transfer rate constant varies substantially with immobilization strategy and electrode surface composition. The variation in thermodynamics and kinetics for cytc immobilized by adsorption will be presented and explained based on the electrostatics of the cytc/modified electrode complexes. In addition, the protein response with changing composition of the SAM and protein surface modification will be discussed.
2009 American Chemical Society in Miniature Poster Presentations 5
2009 American Chemical Society Student Affiliates, Duquesne University
Poster Number 17
Ascorbic acid (Vitamin C) as an environmentally friendly reducing agent in copper catalyzed atom
transfer radical addition. Matthew J. W. Taylor, William T. Eckenhoff, Tomislav
Pintauer Department of Chemistry and Biochemistry, Duquesne
University Atom transfer radical addition (ATRA) is one of the fundamental reactions in organic synthesis. Until recently, ATRA has not been an economical method for the formation of carbon-carbon bonds because of the relatively high catalyst loading required (typically 5-30 mol%) and system’s low tolerance for oxygen contamination. To simplify and improve this chemistry, copper catalyzed ATRA reactions were performed in limited quantities of air using ascorbic acid as a reducing agent. Small amounts of ascorbic acid dissolved in water successfully reduced the metal complex allowing ATRA to proceed at remarkably low catalyst loadings (<<1mol% relative to olefin). The use of ascorbic acid as metal reducing agents eliminates radical termination reactions or chain transfer reactions caused by AIBN radicals, which has also been employed as a reducing agent in air at higher concentrations. In addition, ascorbic acid is known to have high biocompatibility, making this method even more environmentally friendly.
Poster Number 18 Investigation of fluxional processes occurring in copper-catalyzed atom transfer radical addition
Ashley B. Biernesser, William T. Eckenhoff, Tomislav Pintauer
Department of Chemistry and Biochemistry, Duquesne University
The process of atom transfer radical addition (ATRA) has been used to add halogenated compounds across carbon-carbon double bonds in alkenes and alkynes by a radical process since the 1940’s. Recently a technique has been utilized that significantly decreases the catalyst loading required for copper mediated ATRA by carrying out the reactions in the presence of radical initiators which serve as a reducing agent to regenerate the catalyst. Previous research has shown the successful addition of bromoform (CHBr3) and carbon tetrabromide (CBr4) to 1-hexene, 1-octene, and 1-decene in air in the presence of the radical initiator 2,2’-azobisisobutyronitrile (AIBN). The effect of tetrabutylammonium bromide (TBABr) and tris(2-pyridylmethyl)-amine (TPMA) concentrations on [Cu(TPMA)Br][Br] catalyzed ATRA will be investigated to determine whether fluxional processes such as ligand dissociation or halide anion dissociation are occurring. The effect on the activity of the catalyst will be determined by increasing the Br- and TPMA concentrations in solution.
Poster Number 19 Heteroarotinoids induce tissue
transglutaminase in human erythroleukemia cells.
Erin M. Lawrence*, Brandon W. Wilds, Ashley N. Dawson, Tim L. Evans, Paul J. Birckbichler
Departments of Chemistry and *Biology, Slippery Rock University
All trans-retinoic acid is a naturally occurring molecule that is responsible for apoptosis and/or differentiation. Heteroarotinoids (Hets) are a new class of structural analogs of retinoic acid. We hypothesize that Hets will induce tissue transglutaminase, an enzyme that can produce intermolecular isopeptide crosslinks and also exhibit cell-signaling activity. To test this hypothesis, human erythroleukemia cells were cultured for up to 72 hr with retinoic acid (positive control for tissue transglutaminase induction), DMSO (negative control for tissue transglutaminase induction), and various Hets (test compounds). Het-treated cultures showed elevated levels of tissue transglutaminase and apoptosis relative to retinoic acid and DMSO-treated cultures. The results support the hypothesis and offer an additional cellular model for testing the efficacy of Hets as a potential cancer chemotherapeutic agent.
Poster Number 20
Copper Catalyzed Atom Transfer Radical Addition (ATRA) at Low Temperatures using Reducing Agent
Triethylborane/air Sean Noonan, William T. Eckenhoff, Tomislav Pintauer Department of Chemistry and Biochemistry, Duquesne
University
The process of adding polyhalogenated compounds to alkenes using radical means was first achieved in the early 1940's, termed atom transfer radical addition (ATRA). This reaction is typically catalyzed using transition metal complexes. Until recently, the principle drawback of this useful synthetic method was relatively high amount of transition metal catalyst required to achieve high yield of monoadduct (5-30 mol%). The solution to this problem has been found for copper mediated ATRA through the use of reducing agents such as free radical initiators (e.g. 2,2'-azobis(2-methylpropionitrile)(AIBN)). Triethylborane was also found to be an effective reducing agent for copper mediated ATRA. Oxygen is a necessary reagent for this reduction process, eliminating the need for air sensitive techniques. Triethylborane will generate radicals at low temperatures, allowing for future low temperature ATRA.
2009 American Chemical Society in Miniature Poster Presentations 6
2009 American Chemical Society Student Affiliates, Duquesne University
Poster Number 21 Analysis of G quadruplex formation by elongation
factor 1A Jessica N. Rabuck, Timothy L. Evans, Mihaela-Rita
Mihailescu
Department of Chemistry and Biochemistry, Duquesne University
Fragile X Syndrome is the most common form of inherited mental retardation. The syndrome is caused by the loss of the fragile X mental retardation protein (FMRP) expression. FMRP is a protein that binds to specific messenger RNAs and regulates their translation. Although not all FMRP mRNA targets are known, an mRNA of particular interest is the elongation factor 1a (EF1A) mRNA. FMRP has been shown to bind to this RNA, but it is not clear if these interactions are mediated by the presences of a G quadruplex in EF1A mRNA. Prior studies indicate that the binding of at least a sub-set of mRNA targets involves the recognition of their G quadruplex structure by the protein RGG box domain. In this study we translated, dialyzed, and concentrated EF1A mRNA and used circular dichroism spectroscopy to elucidate if EF1A mRNA forms a G quadruplex structure.
Poster Number 22
Parameterization of small molecules that interact with the dopamine active transporter Jonathon D. Gibbons, Jeffry D. Madura
Center for Computational Sciences, Department of Chemistry and Biochemistry, Duquesne University
Many molecules. bind to the dopamine active transporter (DAT), like antidepressants and narcotics. Some of these molecules block dopamine re-uptake from the synaptic cleft. This causes an excess of dopamine to remain in the synaptic cleft, which can lead to euphoric like feelings. How and why specific molecules bind to and inhibit DAT is of high pharmacological interest. To study the binding of substrates to DAT, force-field parameters are needed for: dopamine, cocaine, mazinol, clomipramine, imipramine, and desimipramine. Lennard-Jones parameters were taken from the OPLS-AA force-field and partial charges were obtained from Hartree-Fock 6-31G* gas phase calculations using Gaussian. The parameterized molecules were then bound to the leucine transporter (LeuT), a DAT homolog. Monte Carlo Simulations for Biomolecules (MCPRO) was used to calc. binding free energies of these complexes. Relative free energies of solvation have been calculated for desimiprmaine to imipramine, clomiramine to desimipramine, and imipramine to clomipramine.
Poster Number 23 Solid-State Microwave Irradiation of Intermetallic
Compounds Casey G. Lipovsky, Jonathan W. Lekse, Jennifer A.
Aitken
Department of Chemistry and Biochemistry, Duquesne University
Intermetallic compounds can exhibit a wide variety of useful properties such as, superconductivity, shape-memory and magnetoresistance, among others. They are traditionally synthesized via high temperature solid-state reactions. Solid-state microwave synthesis of intermetallic compounds is a relatively new and unexplored application of microwave irradiation that possesses a number of benefits compared to other synthetic methods. Reaction times are shorter, 10 to 20 minutes for the microwave method, compared to multiple days for some traditional preparations. Shorter reactions save both time and energy. However, the solid-state microwave synthetic method is not well understood. A number of variables have been identified including, grinding time of reactants, sample volume, irradiation time and sample geometry. Microwave experiments in a number of intermetallic systems including Bi-Ni, Ni-Sn and Ni-Fe have been performed and analysis of the products will be discussed.
