Chemistry & Biochemistry
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Item Synthesis and characterization of novel copper(I) and silver(I) mixed ligand complexes(2024-05) Hitt, Britney; Omary, Manal; Beatty, John; Salazar, GustavoThis thesis is a study of the synthesis and characterization of different novel mixed ligand coinage metal complexes. It discusses one main project divided by three chapters covering the synthesis, structure, and characterization of copper(I) and silver(I) complexes, photophysical properties, and detection limits of volatile organic compounds. Chapter one discusses the introduction to trinuclear pyrazolate complexes of d10 coinage metals, metal-ligand bonding, N-donor azolate ligands, mixed metal-ligand complexes, factors affecting photophysical properties, copper(I) halide clusters, and potential applications such as metal-organic frameworks (MOFs), solar cells, organic light emitting diodes (OLEDs), and potential gas/vapor sensors for volatile organic compounds (VOCs). Chapter two involves the different synthetic routes, solvent-mediated and solventless, of copper(I) and silver(I) mixed-ligand complexes and their characterization by melting point, FTIR, thermogravimetric analysis, elemental analysis, photoluminescence, and 1H NMR. Chapter three will be a conclusion of the compiled results from chapter two and their potential applications.Item Investigating the effect of unripe grape juice on taste-relevant compositions of two white wines(2024-05) Pham, Thi Diem Thuy; Du, Xiaofen; Wang, Danhui; Beatty, JohnThis study aimed to investigate °Brix, pH, TA, five sugars, six organic acids, total polyphenols, six phenolics, 20 free amino acids, and five 5′-nucleotides in one verjuice, five ripe grape juices, and five wines. Folin–Ciocalteu was used to quantify total polyphenols, HPLC was used to quantify sugars, organic acids, phenolics, selected free amino acids, and 5′-nucleotides, while GC-MS was used to quantify major free amino acids. The results showed wines fermented from ripe grape juice including 11% verjuice compared with wines without verjuice addition: the °Brix, sugars, total polyphenols, and amino acids were unchanged; pH decreased ~1.1 times, TA increased ~1.3 times, caftaric acid increased ~1.4 times; caffeic acid decreased ~1.4 – 1.9 times; malic acid increased ~1.8 times; 5′-AMP decreased ~1.2 times. These taste-relevant compositions were unchanged in wines fermented from ripe grape juice with 2.2% verjuice addition compared with wines fermented from ripe grape juice alone.Item Green chemical recycling of poly (bisphenol a carbonate) using microwave synthesis(2024-05) Gallenstein, Raven Marie 2000-; Salazar, Gustavo; Beatty, John; Shiru, LinWith an increase in use of electronics and a decrease in their life span there has been an exponential increase in electronic waste. One of the largest materials used in electronics is a plastic called poly (bisphenol A carbonate) a complex plastic with high thermal stability and strength. Due to its complex structure this poly (bisphenol A carbonate) is difficult to recycle and often just ends up in landfills. In order to mitigate that we created a baseline microwave-assisted methanolysis of the polymer into its monomers bisphenol A and dimethyl carbonate. With methanol alone in the microwave we obtained yields of 98% for a time of 25 minutes at 155 °C. Additionally we found that the transesterification of poly (bisphenol A carbonate) does not undergo acid catalyzed transesterification with methanol as its primary reactant.Item Bringing photodegradation of plastic waste into the “green age” through off-grid sustainable energy(2024-05) Akinniyi, Akiwande Solomon 1993-; Salazar, Gustavo; Mirsaleh-Kohan, Nasrin; Beatty, JohnPlastic pollution continues to be a problem despite the current efforts in physical and chemical recycling. Moreover, the faster turnover rate on electronic devices by all consumers continues to increase the generation of plastic waste; consequently, the pollution generated also increases worldwide. Despite breakthroughs that have been achieved, the chemical recovery of complex plastics is still a difficult challenge plaguing society today. Some newer approaches for its management are starting to surge; in fact, one recent example is the use of photochemical degradation as a way of breaking down complex polymers such as those found in category 7 of the resin code. While photodegradation of these polymers has seen significant findings over the years, it remains economically costly, and limited to the laboratory scale. This project introduces the preliminary findings of our own implementations of potential “greener” alternatives to the typical photochemical methodologies while also sharing the design process for increasing photodegradation efficiency. By making use of renewable energy light sources that are commercially available we present our prototypes of an off grid photoreactor. The photo-oxidation results gathered in the study will not only prove that these green methods are practical but also act as the first step for introducing a more sustainable form of photodegradation for polymers, which is not only eco-friendly but cost effective for future potential commercial applications.Item Non-thermal plasma synthesis of organic feedstock from carbon dioxide and nitrogen(2024-05) McNeill, Alice 1999-; Beatty, John; Mirsaleh-Kohan, Nasrin; Salazar, GustavoThe concentration of CO2 in the atmosphere is increasing at a rate that poses harm to the environment, with the full extent of consequences unexplored. The rising population and increasing burning of fossil fuels over the past centuries is draining natural resources while contributing to deteriorating air quality. Exploration of alternative energy generation is ongoing, although increasing levels of CO2 remain in the atmosphere until reacted or extracted. Plasma, an ionized gas considered the fourth state of matter, is examined in this research as a method of reacting CO2 and N2 to produce carbon and nitrogen-based products of intrinsic value. A custom non-thermal plasma system was designed using a high voltage power supply, chemical-resistant tubing, brass supports, and a grounding system. The conductive materials copper and tungsten were tested to determine plasma activation capability, the ability to maintain stable plasma, and the lifetime of the metals. There are several advantages to the system designed in this research, the primary being that a CO2 reduction of 33% was achieved. In addition, the lifetime and reusability of all materials was considered as to meet Green Chemistry project aims. Using Fourier-Transform Infrared Spectroscopy (FT-IR) and Residual Gas Analysis with Mass Spectrometry (RGA-MS), the products from a CO2 plasma include carbon monoxide (CO) and oxygen (O2). Trials with a CO2 and nitrogen (N2) plasma suggest that production of nitric oxide (NO), nitrogen dioxide (NO2), CO and O2 is possible. Raman spectroscopy and Scanning Electron Microscopy (SEM) were utilized to characterize the electrode conditions.Item Syntheses and characterizations of homoleptic and heteroleptic copper complexes with monocyclic and polycyclic azine ligands(Dec-23) Kouadio, Halima; Omary, Manal; Mirsaleh-Kohan, Nasrin; Salazar, GustavoThis thesis is concerned with the following ligands to use to coordinate and react to copper: a pyrimidine: niacinamide, the polyazine monocyclic triazine: cyanuric acid, and bicyclic N- donating hydrocarbons: quinoxaline and caffeine. When reacted with cuprous salts consisting of organic ligands they form multi-ligand coordination supramolecular architectures (1) or halides to form copper halide clusters. In the novel compounds, metal-metal interactions occur, which exhibit low-lying triplet state charge transfers, allowing the tunability of a photon-emitting compound which is expected to form the emission. Cuprous metal centers also possess the ability to self-assemble to form coordination polymers. Group 11 d10 coinage metals exhibit strong metal-to-ligand charge transfers (MLCT) as well.(50) Characterization of all compounds was completed using thermogravimetric analysis, X-ray crystallography, Fourier transform infrared spectroscopy (FTIR), and photoluminescence spectroscopy. The acquired data is analyzed and discussed further in the following thesis.Item Identifying chlorhexidine and sodium hypochlorite reaction products and the environmental implications of its interaction with cotton fibers(Dec-23) Huynh, Stacy 1997-; Beatty, John; Salazar, Gustavo; Lin, ShiruChlorhexidine is heavily used in the medical and dental field and is prescribed for multiple uses related to healthcare. When in contact with sodium hypochlorite, chlorhexidine breaks down into several toxic compounds that are not fully understood, and these compounds have impacts on the environment and human health, due to its heavy use in the medical field. Chlorhexidine breaks down into compounds that permanently adhere to and damage the cellulose fibers found in cotton fabrics and alter the visible quality of fabric, which leads to re-washing of fabrics or outright disposal of fabric due to the staining and damage. Chlorhexidine is also used in conjunction with sodium hypochlorite in dental procedures, such as root canals, and the toxic nature of this interaction is not fully understood. Previous studies have identified several products of this reaction, one being para-chloroaniline, suggesting that chlorhexidine should not be used in conjunction with chemical oxidizers like bleach until the toxic products are further studied and identified. Understanding how chlorhexidine interacts with textile fibers like cellulose will save water and cotton fabric from being prematurely disposed of and negatively impacting the environment. This project will work to understand the reaction between chlorhexidine and sodium hypochlorite, the toxic products that result from this reaction, and its interactions with cotton fiber textiles to reduce its impact on health and the environment.Item HPLC analysis to assess efficacy of cisplatin, nedaplatin, and oxaliplatin(Dec-23) Hernandez, Jessica 1990-; Mirsaleh-Kohan, Nasrin; Beatty, John; Salazar, GustavoPlatinum drugs are one of the most widely used agents against cancerous cells. Cisplatin’s chemotherapeutic efficacy is limited by the increase of tumor resistivity and unwanted side effects. Cisplatin’s cytotoxicity is linked to its ability of forming 1,2-intrastrand adducts with adjacent guanine (G) bases. An analytical method to detect and quantify the amount of platinum bound to DNA is necessary to enhance and develop anticancer drugs. In this work, High Performance Liquid Chromatography (HPLC) analysis was performed to assess the binding of cisplatin, nedaplatin, and oxaliplatin to the dinucleotide dGpdG. By examining the concentration ratios and incubation periods at 37 °C, we measured the amount of platinum drug reacted with DNA (platination rates) indicating the percentage of Platinum-DNA (Pt-DNA) adducts. Cisplatin proved to be the most effective, followed by nedaplatin, and then oxaliplatin. This research has implications in designing more efficient anticancer drugs.Item Synthesis and characterization of diverse copper halide complexes with a range of heterocyclic ligands(Dec-23) Diaby, Aminata 1988-; Dr. Manal Omary; Mirsaleh-Kohan, Nasrin; Dr. Richard SheardyThis study aimed to compare the stability, physical, and chemical attributes of Cu(I) and Cu(ACN) metals, investigating their resemblances and disparities. It comprises approximately 137 pages, encompassing 90 figures, 16 tables, and references. The research focused on synthesizing and characterizing Cu(I) complexes with azole family ligands. Two methodologies were applied: the first involving CuI and Cu(CH3CN) (where X = I or CH3CN) reacting with single ligands like 3,5-diisopropylpyrazole, 3,5-diphenolpyrazole, 3,5-(tert)-butylpyrazole, and 5-(4-chlorophenyl)-1H-tetrazole. The second utilized Cu(CH3CN) with mixed ligands specifically 3,5-diphenolpyrazole and pyrazine, as well as 3,5-(tert)-butylpyrazole and pyrazine. Complex synthesis occurred via solvent-mediated routes using the Schlenk technique and solvent-free reactions with mechanical grinding. Comprehensive characterization involved techniques such as melting point determination, solubility tests, luminescence spectroscopy, FT-IR, TGA, elemental analysis, NMR, and X-ray crystallography. Ligands were characterized using the same listed techniques to understand changes. All synthesized products underwent thorough characterization using diverse analytical tools.Item Preparation for college chemistry: high school and college perspectives(1998-05) Wood, KevinItem Synthesis of doxorubicin-protein conjugates via cobalt coordination chemistry(May-23) Colion, Sara; Petros, Robby; Beatty, John; Mirsaleh-Kohan, NasrinThe use of nanotechnology-based drug delivery systems in the context of cancer treatments has the potential to help target drug chemotherapeutics to tumor cells more precisely while simultaneously reducing off-target toxicity. One of the most prescribed chemotherapeutics, doxorubicin, is an anthracyclines drug that is effective in treating cancer; however, the drug exhibits dose-limiting cardiotoxicity. Dox intercalates DNA, resulting in the deterioration of DNA strands and the ultimate inhibition of DNA and RNA synthesis. Doxorubicin’s chemical structure contains a primary amine group that can be used to crosslink it to a protein. This project focuses on using cobalt coordination chemistry as a novel crosslinking strategy to synthesize conjugates of Dox bound human serum albumin (HSA). The synthesis of conjugates of Dox with HSA will be discussed along with methods for characterization via HPLC that allow the number of Dox molecules bound per protein molecule to be determined.Item The synthesis and mass spectral studies of t-butyl(deuterated) thiophenes(1968-06) Fowler, Rosemary; Ludeman, Helen; Foster, Norman; Mecay, WilliamThe synthesis and mass spectral studies of t-butyl (deuterated) thiophenes were undertaken to aid in elucidation of the mass spectral fragmentation routes of the unlabeled t-butylthiophenes. The desired 2-(t-butyl chloride-2H9) thiophene and 3-(t-butyl-2H9 thiophene were synthesized by the interaction of 2-theinylmagnesium bromide and the t-butyl chloride-2H9 forming both the 2- and 3-isomers. The isomers were separated by preparative gas chromatography/ The isotopic purity of the 2-(t-butyl-2H9) thiophene was 96.3% and for the 3-(t-butyl-2H9) thiophene was 96.7%. The 2, 5-di(t-butyl-5-2H9) thiophene and the 2, 4-di(t-butyl-4-2H9) thiophene were synthesized by the interaction of 5-t-butyl-2-thienyl magnesium bromide and the t-butyl chloride-2H9 forming both the 2, 4-isomer and the 2, 5-isomer. The isomers were separated by the preparative gas gas chromatography. The isotopic purity of the 2, 5-di(t-butyl-5-2H9) was 98.7% and the 2, 4-di(t-butyl-4-2H9) thiophene was 95.22% Mass Spectral studies of the 2-(t-butyl-2H9) thiophene and the 3-(t-butyl-2H9) thiophene confirmed the direct losses of methyl-2H9 groups from the t-butyl group. Preferred successive losses of methyl-2H3 groups occurred in the fragmentation of the 2-isomer, whereas loss of the t-butyl group is the preferred fragmentation route in the 3-isomer. Positional substitution is an important influence on the mode of fragmentation of the various isomers. The steric relationships of the t-butyl group to the rest of the molecule differs depending upon the location (2 or 3) of the t-butyl group. The favored interaction between the deuterium of the t-butyl group and the sulfur atom are related to the location of the t-butyl group. Mass spectral studies of the 2, 5-di(t-butyl-5-2H9) thiophene and the 2, 4-di(t-butyl-4-2H9) thiophene confirmed that two successive losses, one of methyl and one of methyl-2H3 occurred. Preferential losses of methyl and methyl-2H3 are favored in the 2, 5-isomer, whereas the loss of a t-butyl group is favored by the 2, 4-isomer to a considerable extent and apparently occurs with almost equal probability from either position. The fragmentation of the 2, 5-isomer differs from the 2, 4-isomer in ion production and in the intensity of the ions formed at high voltage. These differences may be related to the steric effects and the interaction of the deuterium of the t-butyl group with the sulfur atom. Additional study of the existing mass spectral data presented is expected to yield considerable information on the fragmentation pathways. The Friedel-Crafts alkylation of the 2-t-butylthiophene with t-butyl chloride-2H9 yielded 2, 5-di-t-butylthiophene, 2, 5-di(t-butyl-5-2H9) thiophene, 2, 5-di(t-butyl-2, 5-2H18) thiophene, 2, 4-di(t-butyl-2, 4-2H18) thiophene. The Friedal-Crafts alkylation of the 3-t-butylthiophene with t-butyl chlodide2H9 yielded a product containing equal amounts of 2, 4-di(t-butyl-2-2H9)thiophene and 2, 4-di(t-butyl-2-2H9)-thiophene 5-2H1. Studies to elucidate the mechanism of these reactions are in progress.Item Spectrometric studies of 4-substituted phthalic anhydrides and phthalimides(1971-10) Lee, DaisyItem Design and photophysical characterizations of new copper(I) and silver(I) mixed ligand complexes with “green chemistry” incorporation(1/25/2022) Jawaid, Ramsha; Rawashdeh-Omary, ManalThis thesis is a study of mixed ligand coinage metal complexes. It has 122 pages, 68 figures, 14 tables, and the references. It discusses one main project divided by three chapters describing in general the synthesis, structure and spectroscopic studies of silver (I) and copper (I) complexes. Chapter I discusses the introduction to trinculear pyrazolate complexes of d10 coinage metals, N-donor heterocyclic ligands, polycyclic aromatic hydrocarbon ligand, mixed-metal and mixed-ligand complexes. It also investigates the impact of structural factors and various synthetic conditions on photophysical properties as well as the potential applications including sensors for (VOCs), metal-organic frameworks (MOFs), solar cells and organic light emitting diodes (OLEDs). Chapter II involves both solvent-mediated and solvent-less synthetic routes of silver (I) and copper (I) complexes and mixed-metal and mixed-ligand complexes and their characterization through elemental analysis, x-ray crystallography, melting point, photoluminescence, 1H NMR, FT-IR, absorption spectroscopy and thermogravimetric analysis. Chapter III summarizes the conclusion of the results obtained in chapter II and the expected applications of similar compounds in the industry.Item Synthesis of doxorubicin-albumin conjugates via cobalt coordination chemistry: The effect of reaction conditions on overall protein stability(3/30/2022) Patel, Ashik; PETROS, ROBBYThe applications of nanotechnology in designing better treatments shows great promise in lessening the burden of chemotherapy while increasing therapeutic effect. Protein-drug conjugates are a rapidly expanding family of therapeutics that hold potential for ameliorating off-target toxic effects observed in chemotherapy. In this context, human serum albumin could act as a nanoscale delivery vector to alter the biodistribution of attached therapeutics. This research explored the use of cobalt coordination chemistry in the synthesis of Dox- albumin conjugates. Doxorubicin was chosen because it contains a primary amine that could be crosslinked to protein using cobalt coordination chemistry. The effect of pH and reaction time on the synthesis of conjugates was investigated. Samples were characterized by High Performance Liquid Chromatography, Dynamic Light Scattering, and Differential Scanning Calorimetry. Optimized reaction conditions for synthesizing conjugates with varying numbers of dox molecules per protein was a major focus of the research.Item Synthesis of doxorubicin-protein conjugates via cobalt coordination chemistry: Conjugates of transferrin and immunoglobulin G(11/8/2021) Carvajal de Luna, Juan JoseProtein-drug conjugates are a rapidly expanding family of therapeutics that hold significant potential to ameliorate off-target toxic effects commonly observed in patients undergoing chemotherapy. chemotherapy. In this context, the protein acts as a nanoscale delivery vector that alters the biodistribution of the drug upon administration by restricting its unhindered distribution in vivo. This thesis explores the use of cobalt coordination chemistry in the synthesis of doxorubicin-protein conjugates. Previous work has shown that cobalt can be used to crosslink amine-containing molecules in a reversible reaction that only utilizes the lone pair of electrons on nitrogen to form a dative bond with cobalt. Doxorubicin was chosen for initial studies because it contains a primary amine that could be crosslinked with lysine residues on a protein to form a protein-drug conjugate. Conjugates of dox with albumin, transferrin, and immunoglobulin G were investigated to demonstrate the broad applicability of the method for bioconjugation reactions. Drug loading was investigated by HPLC, and the conjugates further characterized by dynamic light scattering, calorimetry, and cytotoxicity. Details of the effects of reaction conditions on synthesis of stable conjugates will be discussed.Item Studies on the E-loop of human glutathione synthetase(9/15/2021) Haynes, Lindsey Cameron; Sheardy, RichardGlutathione (GSH; L-γ-glutamyl-L-cysteinylglycine), an abundant antioxidant, is synthesized intracellularly in two sequential ATP-dependent steps. Human glutathione synthetase (hGS), the second step, ligates γ-glutamylcysteine (γ-GC) to glycine forming GSH. hGS, an obligate homodimer, displays negative cooperativity to the γ-glutamyl-substrate; thus, binding of γ-GC to one subunit decreases its affinity in the second subunit. The recently found E-loop (A210-Q211-E212-K213-E214-R215-N216) is highly conserved (>66%) in mammals; however, only four residues are conserved in other eukaryotes (>49%). E-loop is near the carboxyl of the γ-GC substrate; therefore, we hypothesize it is important for binding and catalysis. Point mutations of these conserved E-loop residues (Q211A, E214S/A, R215A, N216A/V) were prepared (site-directed mutagenesis). After expression, purification and assays, our results show mutations on the E-loop cause changes in activity, γ-GC substrate binding, and negative cooperativity relative to wild-type hGS. Thus, E-loop is crucial to hGS function.Item Synthesis of doxorubicin-ablumin conjugates via cobalt coordination chemistry: The effect of reaction conditions on overall protein stability(7/23/2020) McGhee, Avione; Petros, RobbyPolymer-drug conjugates have become a common tool in therapeutics to reduce the chances of pharmacotoxicity, often seen in patients undergoing chemotherapy, and to enhance targeted drug delivery. The demand for more novel forms of drug delivery has increased the efforts to develop new drug designs. Our research utilizes cobalt coordination chemistry for the synthesis of protein-drug conjugates. More specifically, this researched was aimed at crosslinking human serum albumin (HSA) and Doxorubicin via cobalt coordination chemistry. In a reversible reaction, cobalt can be used to crosslink amine-containing molecules; such as the primary amine contained in Doxorubicin and the lysine residue of HSA, via coordinate covalent bonding. The ultimate goal of this research endeavor is to alter the biodistribution of Dox in vivo to reduce the systemic toxicity of the drug, which displays dose limiting cardiotoxicity. The use of high- performance liquid chromatography (HPLC) and dynamic light scattering (DLS) were used in identifying optimal reaction conditions for the synthesis of an HAS-Dox conjugateItem Characterizing the thermodynamic parameters of anti-cancer drug Carboplatin and DNA through Spectroscopic techniques(6/3/2020) Williams, Sara M; Mirsaleh-Kohan, NasrinSpectroscopic techniques have been employed to understand the interactions and thermodynamic parameters between the anti-cancer drug Carboplatin and the DNA oligomer COTAR 2: ATT AAT GGA TCC ATT AAT. This is a self-complementary sequence that has been previously shown to bind [Co(NH3)2(OH2)2]+3 with high specificity and is of interest because it contains two isolated G-G sites. Both Cisplatin and Carboplatin are known for binding preferentially to G-G sites. These anti-cancer drugs are commonly used in chemotherapeutic treatments and are known to have adverse side effects. In order to improve treatment options, it’s necessary to understand the molecular basis of their interactions with DNA. The binding of Carboplatin with COTAR 2 has been analyzed using Circular Dichroism (CD), Surface−Enhanced Raman Scattering (SERS), and UV-Vis Spectroscopy. The combination of these techniques allows for better understanding of structure and stability of platinum-DNA complexes, as well as binding kinetics. In this thesis, the results of these studies will be presented, and our current understanding of this interaction will be discussed.