Loading…
2016FallSymposiumURCreativityEngagement has ended

Sign up or log in to bookmark your favorites and sync them to your phone or calendar.

Chemistry [clear filter]
Tuesday, December 6
 

8:00am

New Chemistry: Embracing The Human Element
In the twentieth century, chemistry’s linear profit-driven model made profound discoveries — and consequently large amounts of toxic waste and byproducts — which greatly contribute to the modern challenges humanity faces. This oversight provoked the adoption of practices and principles such as green chemistry and green engineering as a way to practice high-level chemical experimentation without acting unsustainably. With the growing integration of green chemistry and engineering in industry and academia, Paul Anastas’ talk Green Chemistry Next highlighted the lingering issue of “preventing getting stuck in a metric driven loop”. We began to seek out why this might happen, realizing the necessity to re-ask “What does it mean to be chemists, members of society, and human?"" In response to these questions, we took a humanistic approach and began to address key components needed to help students rise to the challenges in the new era of chemistry. New chemistry is intended as a guide to allow society and chemists to prosper and grow sustainably, by acknowledging the human element and finding ways to cooperate with it rather than control it. New chemistry encourages a shift away from shareholder and consumer desires as the primary driving force behind research, instead impressing ethical guidelines that assist chemists in devising their new role in society as environmental and social stewards. These guidelines help them to ultimately embrace green chemistry and engineering principles, and avoid reverting to the linear thinking which caused these problems in the first place. The introduction of curiosity as a core component of new chemistry allows for continual expansion and intellectual stimulation of the individual, leading to growth in fundamental research and subsequent applied research opportunities, and making innovative breakthroughs inevitable. These components are essential for tackling the increasingly complex problems humanity faces, such as those recently noted by George Whitesides at Harvard: public health, mega-cities, climate instability, and dissipative systems.


Tuesday December 6, 2016 8:00am - 8:20am
014 Zeis Hall

8:20am

QTAIM Study of Bonding in Carboranes

The bonding of boron atoms in carboranes and metalloboranes has been a subject of interest for scientists for several decades due to the number of atoms in close radial proximity of each other despite the fact that it is considered to be electron deficient possessing only three valence electrons.[1] A three-center-two-electron bond has been hypothesized to explain the boron atom’s ability to form more than three bonds within a molecule and several papers have been written supporting the existence of this bonding arrangement.[10-11] This study utilized computational chemistry techniques including the QTAIM method to obtain the electron densities, the Laplacian scalars, charge values, basin paths, Poincare-Hopf algebra, and specifically, a B3LYP DFT method with an ab initio MP2 level of theory, and a 6-311+G(2d,p) basis set to produce a geometric optimization of C2B5H7 and C2B7H9. The Trans-Ring configuration of C2B5H7 was reported as the most thermodynamically stable configuration. The ring critical point ρ(r) values of the Trans-Ring configuration of C2B5H7 and C2B7H9 were reported as lower than the corresponding bond critical point ρ(r) values to which they are attached, all of which indicate that there is not a three-center-two-electron bond present in the molecule. The charge values and Laplacian scalars results indicate fragment behavior, similar to ligand behavior, between the boron and carbon atoms and their corresponding hydrogens. The results lead to the conclusion that ligand close packing and coordination theories, along with Wade’s Rules, give better explanations for the bonding and behavior of closo-carboranes.


Moderators
Speakers
Sponsors

Tuesday December 6, 2016 8:20am - 8:40am
014 Zeis Hall

8:40am

Investigation of Pregnancy Categories and GABAA Receptor Interactions of Common General Anesthetics

This literature based research project investigates the chemical structure of three anesthetic agents and compares them to their given pregnancy category.  Pregnancy categories give the administering physician an idea as to whether the drug will affect the in-utero patient.  Sodium thiopental, a barbiturate, has been used in the medical field since 1934, and it is categorized as a pregnancy category C.  Midazolam is a benzodiazepine derivative; its use began in the 1980’s and it is classified as a category D drug.  Propofol, a category B agent, is unrelated to all other anesthetic agents, its use began in the United Kingdom and New Zealand in 1986.  The three anesthetics of interest have advantages and disadvantages, thiopental and propofol being similar.  Controversy surrounds the claim midazolam causes hypotonia also known as “floppy baby syndrome.”  The anesthetic agents of interest pharmacologically effect the gamma amino butyric acid A receptor (GABAAR), but their effects differ due to the locations of their binding sites.     This research is important because very little is understood about maternal and in-utero physiology, pharmacodynamics and pharmacokinetics of anesthetic agent within the pregnant woman and fetus, as well as the exact interactions that occur between the anesthetic and the central nervous system. 


Moderators
Speakers
Sponsors

Tuesday December 6, 2016 8:40am - 9:00am
014 Zeis Hall

9:00am

Isolation and characterization of antibiotic compounds produced by Gram-Negative bacteria strains Pseudomo nas and C hromobacterium
Multidrug resistant bacterial infections, which arise due to misuse and overuse of antibiotics, are responsible for many nosocomial infections and are a threat to human health. Derivatization of known antibiotic compounds via total or semisynthesis can be time consuming and ineffective at targeting specific bacteria. This investigation focuses on bacteria found in the phytotelmata of Sarracenia pitcher plants and the natural antibiotic compounds they secrete under varying conditions The aim of the project is to find single-producer and co-culture producing bacteria that secrete secondary metabolites effective a broad spectrum of Gram-positive and -negative pathogens. A Pseudomonas (CMCP E3) and Chromobacterium (CP2 SSIV)isolated in this study have been found to be effective against Gram-positive bacteria Sta phylococcus aureus and the fungi Fusarium solani. The bacteria strains were cultured in minimal media containing either succinate or citrate that showed the densest growth after 72 hours. A 6 L citrate culture of the CMCP E3 bacterium yielded on average 32 mg of crude product and 9 mg of antibacterial compound. Optimization of large scale culture of CP2 SSIV and characterization of the antibacterial secondary metabolite produced by CMCP E3 using NMR and mass spectrometry are ongoing.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 9:00am - 9:40am
014 Zeis Hall

9:40am

Soil Characterization at Four Sarracenia Wetlands
Carnivorous plants prefer nutrient poor soils due to their advantage to absorb nutrients through foliar absorption. The endangered species Mountain Sweet Pitcher Plant (Sarracenia rubra ssp. jonesii) inhabits increasingly scarce Southern Appalachian wetlands, and characterizing current soil conditions will allow for detection of nutrient shifts and provide a better understanding of the traits a site would possess in order for Sarracenia to thrive. Soil organic carbon was determined by loss-on-ignition method, and percentage of sand, silt, and clay and soil pH were determined by standard methods. Base cations were quantified via Atomic Absorption Spectrophotometer. At McClure’s fen, organic carbon and CEC appeared to have increased since the data collected in a similar study in 2000, although the values were found to be not statistically different when a Student’s t-test was applied. The average pH at the 0-16 cm depth was lower in 2016 than in 2000, with values of 4.37 and 4.52, respectively. Texture analysis demonstrated that pitcher plants prefer sandy, loamy soils rather than clay.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 9:40am - 10:20am
014 Zeis Hall

10:15am

Diverse Utility and Synthesis of Pyrrole Derivatives of Combretastatin A-4 for Anti-Cancer Purposes

Combretastatin A-4 analogs have been proven to provide anti-inflammatory, antimitotic, anti-invasive, antibacterial and anticancer properties. Specifically, chalcone analogs- the least studied- have demonstrated positive bioactivity in the apoptosis of certain types of cancers. Derivatives of these analogs may lead to the production of pyrroles, particularly, Lamellarins. Chalcone derivatives with structural features parallel to those of the isolated natural product of the South African bush willow, Combretastatin A-4, maintain the function of binding to the β-tubulin, which interrupts vascular function in mitotic replication- including those of MDR cancer cells. This natural compound, however, is not soluble within the bloodstream. This research examines the synthesis of pyrrole analogs derived from tubulin binding chalcones. Specific substitutions of these chalcones, which were synthesized via the Claisen-Schmidt methodology, were established in order to prospectively increase the activity of this molecule within the bloodstream. The final product maintains the trimethoxy feature of CA-4 in order to bind to the colchicine binding site of the β-tubulin.


Moderators
Speakers
Sponsors

Tuesday December 6, 2016 10:15am - 11:15am
014 Zeis Hall

10:15am

Effects Of Oleylamine To Oleic Acid Ratios In The Surfactant-Assisted Synthesis Of Anisotropic Brookite Titanium Dioxide Nanoparticles
Titanium dioxide (TiO2) nanoparticles (NPs) have a wide variety of properties that can be utilized for industrial and academic functions. TiO2 is a common and non-toxic material that can be used in the photocatalysis of organic molecules. The most common forms of these particles are anatase and rutile. This experiment focused on the synthesis of the less common, brookite crystal structure. In addition, we looked at how different ratios of Oleylamine (OLAM) in the synthesis affect the growth of the nanocrystals. Synthesized particles were characterized using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 10:15am - 12:00pm
014 Zeis Hall

10:15am

Paclitaxel Coated Gold (Au) Nanoparticles (NPs) For Drug Delivery In Chemotherapy
Current chemotherapy medications can not tell healthy cells and cancerous cells apart. This inability of distinction leads to healthy cell toxicity. Nanomaterials for drug delivery can be used to directly target cancer cells with a smaller dose of medication, reducing the risk of toxicity to the healthy cells. The most promising are Au NPs, which can be loaded with Paclitaxel. Paclitaxel is a chemotherapy medication used for breast cancer, and is regarded as one of the most effective chemotherapy medications. Intravenously (IV) administered Paclitaxel-coated NPs require no premedication before treatment, and can be administered in 30 minutes. In this presentation, synthesis and characterization of Paclitaxel-coated NPs is presented.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 10:15am - 12:00pm
014 Zeis Hall

12:00pm

Chemical Characterization of Hyder Pasture
A chemical characterization of water and soil from the newly restored Hyder Pasture fen in Flat Rock, North Carolina was obtained. This represents the first assay performed on the site since the restoration. Little data was available from pre-restoration analysis for comparison. However, what was available was compared to this study to investigate any observable changes. Several methodologies were utilized in order to ascertain prominent chemical features of the system supporting a population of endangered bunched arrowhead (Sagittaria fasciculate). Water samples were analyzed by HP-LC Ion Exchange to determine what nutrients were present in various bodies of water at the site. Soil samples were analyzed by standard CEC procedures to determine the nutrients and potential productivity of the soil after the restoration. Soil organic carbon was determined by the Loss on Ignition(LOI) method. Scanning Electron Microscopy with EDS was employed in order to qualitatively determine the mineralogy of the soil. The scope of this study was to add to the growing body of work aimed at understanding the requirements of sustainable bunched arrowhead populations. Currently, little research is available to aid in predicting the success of wetland restorations focused on revitalizing or protecting these rare plants. The results were compared to previous work from separate sites containing bunched arrowhead done by previous researchers in order to determine any commonalities among chemical features.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 12:00pm - 12:40pm
014 Zeis Hall

12:40pm

The stability of Glucuronidated Phthalate Metabolites at Various pH’s
Phthalates, found in many household products, have been shown to have a significant impact on human health. In particular, phthalates have been shown to be disruptive to the hormone testosterone. Disruption of testosterone during pregnancy is known to cause a variety of birth defects in male infants including: decreased anogenital distance, as well as, size and function of male reproductive organs. We hypothesize human variability factors, such as, gender, race, smoking status, and age lead to differential risk from phthalate exposure. We seek to understand the effect of varying pH values on the stability of phthalate metabolites in human urine, which can range from 4.5-8.0. This knowledge will improve our understanding of the stability of these compounds. We will also acquire an understanding of the extent to which phthalates may be studied to gain insight into the variation of human susceptibility. The urine samples were analyzed after thawing and then again after altercation of pH and temperature. Urine samples were purified through solid phase extraction and by high performance liquid chromatography. Samples were analyzed with atmospheric pressure chemical ionization tandem mass spectrometry.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 12:40pm - 1:20pm
014 Zeis Hall

1:20pm

Synthesis and antibiotic evaluation of heterocyclic A and C ring depsidone analogs
Depsidones, which are 6,7,6-fused tricyclic natural products, are potent inhibitors of Gram-positive bacteria, with MIC values ranging from 0.1–8.0 μg/mL. This work looks to evaluate the effects of substituting the A and C benzene rings of the natural products with a variety of heterocycles on their antibacterial activity. Synthesis and optimization of pyridine, furan, and thiophene depsidone analogs has been accomplished through a 4-step synthetic sequence beginning from the corresponding 2-bromo-3-carboxylic acid heterocycles. After benzyl protection of the carboxylic acids (82-95% yield) is achieved, the central 7 membered ring of each depsidone analog is produced by first coupling to catechol through a copper catalyzed etherification (7-19% yield), deprotection the benzyl ester, and closing the ring through an intramolecular esterification. Each analog will be tested in an antibacterial bioassay against Staphylococcus aureus to reveal how the changes in the electronic profile affect antibiotic activity.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 1:20pm - 2:00pm
014 Zeis Hall

2:00pm

Instrumental analysis of biologicals from natural water sources

The French Broad River (FBR) serves as the home to several endangered species, raising concern due to the possible presence of endocrine-active compounds (EAC). EACs in wastewater treatment plant (WWTP) effluent have shown to affect stages of sexual development in several aquatic species. In collaboration with the French Broad Riverkeeper Hartwell Carson, and supervised by Dr. John Brock, we will quantify the EAC concentration in WWTP effluent in Asheville, NC. Research has shown that exposure to EACs in WWTP effluent has induced the feminization of fathead minnows, in Ontario, Canada, resulting in a decline of fertilization success; continued decline could lead to extinction (Kidd et al. 2007). EACs have not been measured in the FBR, and we are the first to produce results for EACs. Endocrine-active compounds likely to be found in the FBR include: phthalates, estrogen, bisphenol a (BPA), and nonylphenols (NP). Currently, we have successfully detected multiple phthalate metabolites though the use of a Shimadzu Liquid Chromatograph Mass Spectrometer-8040 (LCMS). Phthalates are used in many personal care products (PCP), and we hypothesize that the amount of phthalates being released from WWTP effluent can be associated with the time of day. Considering PCPs are commonly used in the mornings and before going to bed, we suggest that there may be a spike in concentration at those times. Upon completion of the EAC analysis, the information acquired will describe the effectiveness of WWTP processes in removal of EACs, and increase awareness in the community for environmental sustainability.

 


Moderators
Speakers
Sponsors

Tuesday December 6, 2016 2:00pm - 2:40pm
014 Zeis Hall

2:40pm

Natural Dibenz[b,f]oxepin Compound as a Potential Novel Antibacterial Agent: Synthesis, Evaluation, and Optimization of Empetroxepin A and B

The increase in multi-drug resistant strains of pathogenic bacteria has made the issue of bacterial resistance a global health concern. New classes of antibacterial drug compounds, able to work outside existing mechanisms of resistance, are needed to combat these infections. Natural product-based drug discovery is an effective method in the development of new classes of antibiotics due to the chemically unique structures characteristic of naturally occurring compounds. This study aims to develop a viable antibacterial drug using Empetroxepin A and B, novel dibenz[b,f]oxepin natural products, as the lead compounds. The natural products will be synthesized in seven steps from commercially available 3,4,5-trimethoxytoluene. To date, the first five steps have been completed successfully through a Wittig olefination of trimethylsilane-protected salicyladlehyde with the phosphonium salt generated from the toluene starting material. The desired phosphonium salt was synthesized through aromatic bromination and radical benzylic bromination of the starting material. High yields (68-99%) have been achieved on large scales for each of these steps. Hydrogenation of the alkene bridge formed by the Wittig olefination has also been completed though only low yields have been obtained to date. The remaining steps in the total synthesis include a copper oxide catalyzed etherification ring closure followed by selective deprotection of the methoxy substituents to give both Empetroxepin isomers A and B. Once the synthesis of the lead compounds has been completed, the synthetic route will be used to develop analogs for structure activity relationship studies to optimize the natural product’s antibacterial activity.


Moderators
Speakers
Sponsors

Tuesday December 6, 2016 2:40pm - 3:20pm
014 Zeis Hall

3:20pm

Combretastatin A-4 Analog Bearing Indole Chalcone Moiety
Drugs that target tubulin polymerization have largely been focused on in the field of cancer research. Combretastatin A-4 (CA-4) binds to the colchicine site of ß-tubulin, and therefore inhibits tubulin polymerization. Inhibiting this function leads to cell aptosis in tumoral vasculature, thus producing anti-cancer effects. Structural modifications of CA-4 have been made in various studies to increase the solubility of the compound, as well as binding affinity to the colchicine site. Studies in the literature have shown that incorporating indole and chalcone moiety in analogs of CA-4 has increased the efficacy of the drug. This research focuses on synthesizing an analog of CA-4 in which the trimethoxy A-ring of CA-4 is replaced with an indole ring, and possesses a chalcone core that connects the two heterocyclic rings. Synthesis of the substituted indole utilizes Hemetsberger-Knittel methodology, in which thermolysis of the vinyl azide allows the indole ring to form. The chalcone of interest is formed in the final step from the indole aldehyde and halogenated acetophenone. The brominated acetophenone was synthesized several times in order to acquire enough product so that it could be purified through column chromatography. Various reactions with a previous student's indole aldehyde were attempted, but the trials proved to be unsuccessful. Therefore, the indole synthesis was started from step 1 in order to obtain the desired indole product. So far, a protecting group has been added to a substituted benzaldehyde, which is required for the rest of the synthetic scheme. The indole synthesis needs to be completed so that the desired indole can be reacted with the brominated acetophenone, thus forming the target CA-4 analog.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 3:20pm - 4:00pm
014 Zeis Hall

4:00pm

A Computational Study of Substituent Effects on the Thioallylic Rearrangement Pathway'
This goal of this study was to find the transition state structures and threshold energies of the thioallylic rearrangement mechanism, while observing the effects of different substituents. The initial structure is as follows: R-S-CH2CH=CR2, where the R groups represent different substituents. The substituents were chosen based upon electron donating (R= -NH2; -OCH3), electron withdrawing (R= -CF3), and steric properties (R= isopropyl; benzene) and were tested in a number of combinations on the three possible R positions. The transition state was found to be a short-lived sulfur bridge between the first and third carbon of the structure, resulting in the final state with the sulfur on the third carbon and a shift of the double bond to the first and second carbon (CH2=CHCR2-S-R). The specific energies found for the original thioallylic structure (R1=H; R4=CH3) were 48.0 kcal mol­-1 for the trans orientation and 48.4 kcal mol-1 for the cis orientation. Oxyallylic structures underwent the same calculations to compare the effect of oxygen versus sulfur in the rearrangement. Oxyallylic threshold energy values were 61.1 kcal mol-1 and 61.8 kcal mol-1 for the trans and cis isomers, respectively. The computational methods used in this study include Density Functional Theory (DFT) calculations to find transition state energies and mechanisms, as well as the Quantum Theory of Atoms in Molecules (QTAIM) as a model to visualize electron localization and densities in the described structures. Though this research was purely computational, the results are important to synthetic chemistry and biology. That said, there have been biological and biomedical studies that have found garlic derived organosulfur compounds to have capabilities to inhibit cell proliferation, and act in metabolic processes to aid in the treatment or management of certain diseases. Providing preliminary results on this system can be a beneficial starting point for the research and synthesis of compounds involving the thioallyl.

Moderators
Speakers
Sponsors

Tuesday December 6, 2016 4:00pm - 4:40pm
014 Zeis Hall