The 7th Annual

NC State University

Undergraduate Summer Research Symposium

 

NSF Chemistry REU Program


Abstracts are listed in alphabetical order by the last name of the corresponding author.

 

 


 

 

Student Author(s): 

Aquino, Arianexys

Ballard, Eric

Home Institution:

University of Puerto Rico, Rio Piedras Campus

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Christian Melander/Chemistry

Title of Presentation:

Synthesis and Anti-biofilm Activity of a Diverse Library of Oroidin Analogues Employing an Efficient Reductive Acylation Reaction



Biofilms are correlated with increased morbidity and mortality rates of many infectious diseases. A small library of 2-aminoimidizoles were synthesized and assayed for anti-biofilm activity against several medically relevant biofilm forming bacteria. These compounds are very structurally similar to oroidin and were synthesized through a reductive acylation reaction with acid chlorides, anhydrides and trichloroesters in good to excellent yields as coupling partners. This method represents a significant improvement over previous reaction conditions which were lower yielding, difficult to purify, and limited to trichloroesters. Additionally, analogues not previously accessible are easily prepared with this new method which has allowed for new biofilm modulating motifs to be examined.

 


 

 

 

Student Author(s): 

Cahill, John F.

Home Institution:

St. Ambrose University

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Qiang Liu/Chemistry

Lin He/Chemistry

Title of Presentation:

Surface Assisted Laser Desorption Ionization (SALDI) on Ordered Mesoporous Titania Film and its Imaging Applications

 

 


Surface Assisted Laser Desorption Ionization Mass Spectrometry (SALDI-MS) has gained great research interest as a sensitive, matrix-background-noise free method in low mass molecule detection.  A mesoporous titanium dioxide film with 3-D ordered nanostructure was introduced here as a novel SALDI-MS substrate, which has improved sample stability, robust sample preparation, and fmol detection limit.  The stability of titanium dioxide film over one year storage has been demonstrated.  The low limits of detection of different classic analytes, such as 1,2-Dimyristoyl-sn-Glycero-3-Phosphocholine (DMPC) , Caffeine, Lysine, and Atenolol have been established.  The feasibility of mesoporous titanium dioxide in Imaging Mass Spectrometry (IMS) application has been demonstrated.  The matrix sublimation deposition methods have been established for multiple matrices including 2,5-dihydroxybenzoic acid (DHB), α-Cyano-4-hydroxycinnamic (CHCA), citric acid, and CHCA:Pyridine ionic matrix.  The deposition uniformity was evaluated using optical and SEM methods.  This negates the problem of analyte dispersion suffered by current techniques, especially in tissue imaging where accurate molecule positioning is critical for meaningful analysis.   Concept proof tissue imaging has been achieved using titanium dioxide films with improved imaging sensitivity. It provides a promising new tool for medicinal or pharmacological researchers to accurately identify the spatial distribution of therapeutically important molecules. 

 


 

 

Student Author(s): 

Cross, Amanda J.

Home Institution:

NCSU

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Alex A. Nevzorov/Chemistry

Shikha Misra/ Chemistry

Title of Presentation:

Solid-State NMR in Aligned Samples for Protein Structure Determination in Biological Membranes


 

Transmembrane proteins extend through the entire lipid bilayer of cells. These proteins are important for the pharmaceutical industry as they constitute the majority of prescription drug targets.  The main objective of this experiment is to determine the structures of proteins in their native lipid environment using solid-state nuclear magnetic resonance (NMR). The instrument produces a spectrum with peaks corresponding to unique orientations of the covalently bonded nuclei when a strong magnetic field is applied.  Protein cloning, expression, and purification were performed on two different proteins: the M2 domain of Human Acetylcholine Receptor and the E2 domain of the Sindbis virus.  Further protein purification will be done using fast protein liquid chromatography (FPLC) and then the solid-state NMR will be performed on these proteins.   Also studied were magnetically aligned bicelles, which are composed of long chain and short chain phospholipids, which are used to incorporate membrane proteins. The interaction of free radicals (TEMPOL) on dimyristoyl phosphatidylcholine (DMPC) and diheptanoyl-sn-glycero-3-phophocoline (DHPC) were conducted using 31P solid-state NMR.  The results showed that as the amount of TEMPOL increased the linewidths also increased due to paramagnetic relaxation.   At the same time, this would decrease the temperature required for the formation of bicelles. The line width of the DMPC increased more than the width of DHPC.  If TEMPOL was added in larger quantities, no bicelles were formed.   Solid-state NMR of n-acetyl Leucine crystal was also performed.  Cross-polarization transfer was employed to transfer magnetization from 1H to 15N nuclei of the molecule. This allows one to detect the 15N signal which otherwise could not have been done directly. The peaks in the solid-state NMR spectrum correspond to distinct orientations of the N-H bonds. As the crystal is rotated, the peaks shift, and therefore information about the structure of the crystal can be determined.

 


 

 

 

Student Author(s): 

Etherton, Rachel A.

Home Institution:

Tennessee State University

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Alexander Deiters/Chemistry

Title of Presentation:

Investigating Microwave Activated Biocatalysis

 

 

Enzymes are important to everyday biological function in catalyzing chemical reactions in every organism and in industrial processes.  Microwave irradiation has been used to increase the yield and decrease the time of organic reactions.  However, there are limited investigations showing the effect of microwave irradiation on biomacromolecules.  Microwave irradiation causes molecular rotation from dipole alignment with the external electrical field, which makes polar molecules like peptides and proteins susceptible to the effects of microwave irradiation.  Previous results in the lab suggest that microwave irradiation of hyperthermophilic enzymes leads to enzymatic activation at temperatures lower than their optimal temperature.  We are investigating two different types of enzymes, trypsin which is a mesophilic protease, and CelB which is a hyperthermophilic glucosidaseTrypsin breaks down proteins into peptides by cutting peptide bonds, and is used in proteomics to form peptides from proteins so they can be analyzed by mass spectrometry.  CelB breaks exo-glucosidic linkages for the metabolization of carbohydrates. The objective of this project is to explore the use of microwave irradiation on biocatalysis. In order to explore the effects of microwave irradiation on trypsin and CelB enzymatic reactions were performed at different substrate concentrations, microwave irradiation powers (0- 300W), and simultaneous cooling (air or Coolmate).  The findings demonstrate that trypsin was most effective at 200W of microwave irradiation with simultaneous cooling. CelB was found most active using a Coolmate at 300W and displayed a kcat of 0.47 mM which is comparable to non-microwave conditions at 25oC (0.20 mM).  In conclusion, the data from this research demonstrates that enzymes can be activated at lower temperatures than usual using microwave irradiation.

 

 


 

Student Author(s): 

Jessico, Mary G.

Ondachi, Pauline

Home Institution:

College of St. Scholastica

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Daniel L. Comins/Chemistry

Title of Presentation:

Synthesis of Novel Iodoacetamide Derivatives for Proteomics Research

 


The use of 2-iodo-N-(4-phenylbutyl)acetamide as a cysteine-specific tag was shown to greatly increase the electrospray response of specific peptides using the ALiPHAT strategy (augmented limits of detection for peptides with hydrophobic alkyl tags). The goal of this research was to synthesize variations of this tag and other previously synthesized tags to achieve a greater electrospray response. The tags were altered to increase hydrophobicity, an important factor for achieving improved response. Specifically, key interest was in the synthesis of 2-iodo-N-(4-(3,4,5-trifluorophenyl)butyl)acetamide and 2-iodo-N-(4-(perfluoropyridin-4-yl)acetamide. The primary methodology used to synthesize the new tags was a Negishi cross-coupling mechanism. Ultimately, tags can be used to study cysteine-containing peptides which have little or no electrospray response or can be used to detect peptides at very low concentrations.

 

 


 

Student Author(s): 

Kalman, Steven E.

Foley, Nicholas A.

Home Institution:

Muhlenberg College, Allentown, PA

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

T. Brent Gunnoe/Chemistry

Title of Presentation:

Development of Fe Systems for Olefin Hydroarylation

 

 

Industrially, petroleum and natural gas feedstocks are initially converted through multiple C-C bond forming steps to more complex molecules that account for nearly 95% of all manufactured chemicals.  Unfortunately, current methodologies for these C-C forming steps result in poor selectivity, multiple-step syntheses, high energy consumption and harmful waste generation.  We would like to make use of homogenous transition metal catalysts to combat these synthetic drawbacks.  We have previously synthesized a series of TpRu(L)(NCMe)R {Tp = hydridotris(pyrazolyl)borate; Ru = Ruthenium; L = CO, PMe3, Ppyr3 (pyr = N-pyrrolyl) and P(OCH2)3CEt; R=Me or Ph} complexes which  catalyze olefin hydroarylation.  Building from these previous studies, we are extending our studies to new transition metal paradigms.  As iron (Fe) is readily available and relatively inexpensive, we would like to apply the same hydroarylation scheme to afford an economically viable catalyst for industrial and fine chemical application.  Herein, we report the novel synthetic attempts to develop an Fe hydroarylation catalyst of the type TpFe(L)(NCMe)R (L = CO or PMe3 ; R = Me or Ph), comparative studies between analogous Fe and Ru systems, and initial attempts at olefin hydroarylation catalysis.

 

 


 

Student Author(s): 

Monks, Brendan M.

Home Institution:

Sewanee: The University of the South

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

James D. Martin/Chemistry

Title of Presentation:

Solid State Engineering: Synthesis and Characterization of Various Divalent Transition Metal Complexes

 

 

 Novel metal rich chloride complexes were synthesized and have been shown to contain liquid crystalline phases near room temperature, a feature which could find useful applications in rechargeable ion batteries. Rechargeable ion batteries, such as the ZEBRA battery and Lithium ion battery, have been shown to contain the high charge density and high power density that is required for many modern applications. The downside to these batteries is either their operating temperature is well above that of room temperature or that the material inside the battery degrades over time. These factors affect the life, power density, and possible applications of rechargeable ion batteries. Novel metal rich divalent ammonium chloride complexes were synthesized via a solid state method and were shown to possess multiple liquid crystalline phases at and around room temperature. Using a different inorganic metal and varying the ammonium cation ratio as well as using several alkyl length cations was shown to have an impact on the complex’s melting point along with the temperature range where the complex was liquid crystalline. A solid state synthesis technique was utilized to circumvent the hydration problem that had accompanied solution based chemistry. The properties, characteristics, and phase transitions of the solid synthesis products were analyzed and compared to those of the analogous solution based synthesis products.

 

 

 


 

Student Author(s): 

Moreau, Meghann A.

Home Institution:

Duquesne University

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Paul Maggard/ Chemistry

Lindsay Fuoco/Chemistry

Title of Presentation:

Flux Synthesis and Characterization of Layered Oxyphosphides in the YOMP System (M=Fe, Mn, Cd)

 

 

Syntheses of new classes of superconducting materials have been extensively investigated since their discovery in 1911, owing to their zero electrical resistance and perfect diamagnetism that gives rise to exciting new electronic applications.  An emerging class of new superconductors has recently attracted much attention in the layered rare-earth oxypnictide systems, such as in LaOFeP.  In my research, three new quaternary oxyphosphides in the YOMP system (M = Fe, Mn or Cd) have been prepared in a NaCl/KCl flux, and as well, using high-temperature solid-state reaction methods.  The reaction conditions necessary to form the desired layered yttrium-oxyphosphide phase were investigated within a temperature range of 700°C to 1100°C, for reactant-to-flux ratios of 2:1, 3:1, 4:1, 6:1 and 15:1, and also using different starting reactants (e.g. Y(s), Y2O3 or YP).  The desired products were most successfully formed at 800°C using a 1Y:1M:1P molar ratio and a 1:6 reactant-to-flux ratio.  The resulting products were characterized by powder and single-crystal X-ray diffraction, and resistivity measurements were taken for samples that could be prepared in pure form.

 


 

Student Author(s): 

Morrison, Gregory

Home Institution:

University at Buffalo

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Christopher B. Gorman/Chemistry

Title of Presentation:

Optimizing the Model Reaction for the Synthesis of a Novel Aromatic Ladder Polymer

 

 

The development of ever smaller and faster electronic chips has been limited by the fact that, when made too small, metal wires experience electromigration1 and break.  An organic conductor, on the other hand, should not experience electromigration as this would require the breaking of covalent bonds.  For this reason, a novel aromatic ladder polymer is being investigated as an alternative conductor to metals.  This potentially electrically conductive polymer can be formed from a precursor polymer which is an insulator.  It is therefore believed that direct writing can be used to write features made of this polymer into a film of the precursor polymer.  However, current synthetic methods have failed to produce a stable precursor polymer of an appropriate molecular weight.  Under current conditions, a deprotonation occurs at each monomer subunit and as a result the polymer becomes insoluble and precipitates from solution.  In attempt to overcome this problem, two routes have been explored: to use conditions in which the polymer is not deprotonated and to use conditions in which the deprotonated polymer is soluble.  In order to explore these two routes, a model system has been used in which a related trimer is produced from a dimer and a monomer.  These reactions have been carried out on a milligram scale using a microwave reactor.  The results were analyzed using high performance liquid chromatography. The effects of changing the base and the solvent system have been studied.
(1)    Pang, X; Kriman, A.M.; Bernstein, G.H. J. Electrochem. Soc. 2002, 149, G103-108.

 

 


 

Student Author(s): 

Porter, Vanessa R.

Kennemur, Justin G.

Home Institution:

Eastern Michigan University

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Bruce M. Novak/Chemistry

Title of Presentation:

Relating Reaction Conditions to Regioregularity in the Polymerization of Carbodiimides

 


In order to tune desired physical properties of polymers, regularity within the polymer structure is often required.  One such regularity is regioregularity, which is often governed by the mode of monomer insertion during the propagation of polymer chains.  Currently, there is uncertainty surrounding the achievement of such regioregularity within an asymmetric polycarbodiimide system.  By definition, asymmetric carbodiimides have two different pendant groups and during polymerization, one pendant group will reside with an imine nitrogen while the other resides with an amine.  Thus, an asymmetric monomer affords two regioisomers during the propagation of the polymer.  It is believed that thermal control of the polymerization reaction could have an effect on the regioregularity of monomer insertion, however, until now such an experiment has not been performed.  The purpose of this study is to observe changes in regioinsertion behavior of an asymmetrical monomer as a function of temperature.  The temperatures being studied are approximately 10°C, 35°C, 45°C, and 55°C.  The regioregularity of the polymer is monitored using infrared spectroscopy (IR).  The C=N imine stretch is observed in IR spectra as a strong peak in the range of 2100 cm-1.  By varying the substituent on the imine nitrogen, a change in the electronic or inductive effects of the C=N bond results in an observable change of the IR absorption wavenumber for this bond.  For this reason, the asymmetric carbodiimide monomer used contains an aromatic and an aliphatic pendant group.  When the polymerization of different regioisomers occurs, the resulting imines will absorb at different wavenumbers depending on the pendant group attached to it.  Future research includes testing the reproducibility of obtained results and investigating the different physical properties of each regioregular polymer.

 


 

Student Author(s): 

Turner, Abigail H.

Home Institution:

Mary Baldwin College

Program:

NSF Chemistry REU Program

College:

PAMS

Department(s):

Chemistry

Research Mentor(s)

Edmond F. Bowden/Chemistry

Edward L. D’Antonio/Chemistry

Title of Presentation:

Interfacial Electron Transfer Kinetics of Adsorptively Immobilized Dehaloperoxidase on Self-Assembled Monolayers

 

 

Immobilized enzyme electrocatalysis (IEE) results when a functioning redox enzyme is attached to an electrode in an electroactive state.  IEE provides a basis for a variety of applications in biosensing, biofuel cells, and bioremediation. Essential to the development of such technologies is a thorough understanding of interfacial protein electron transfer (ET) kinetics. The goal of this work was to measure the interfacial ET kinetics of immobilized dehaloperoxidase (DHP), a heme enzyme that catalyzes the dehalogenation of various halogenated phenols, thereby reducing their toxicity. DHP was immobilized by adsorption onto gold electrodes modified by COOH-terminated alkanethiol self-assembled monolayers (SAMs) of varied composition. Presumably, the adsorption results from electrostatic attraction between a lysine patch on DHP and the anionic SAM surface. For 1:3 C7COOH/ C8OH mixed SAMs (6 mM KPB, pH 6), we obtain approximately one-half monolayer of electroactive DHP. Standard electron transfer rate constants (ket°) were determined for the FeIII/  FeII-O2 and FeIII/FeII redox couples of DHP from cyclic voltammograms using Laviron theory. For the FeIII/FeII-O2 reaction, a value for ket° of 0.8±0.2 s-1 was measured. Rates calculated for both redox couples at SAMs of various composition will be presented and discussed in the context of previous work focused on the electron transfer protein cytochrome c.

 

 


 

 

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Last modified June 2008 by Sharon E. Hunt