Chemistry Commons^™

Molecular Dynamic Simulation Studies Of The Androgen Receptor Complexed With 5Α-Dihydrotestosterone And An Allosteric Ligand, Everardo Villarreal Ii

Theses and Dissertations

Receptors are important drug targets for the pharmaceutical industry, since they are involved in many illnesses. Nuclear receptors are a subset of receptors that control a variety of physiological events, by expression of genes from DNA. One of the nuclear receptors, the androgen receptor, is a steroid binding receptor that controls a variety of regulatory and development functions in the body. It is also the cause of some types of cancer, so the inhibition of this receptor is crucial. One of the processes studied to inhibit the function of the receptor is to see if an allosteric ligand, TRIAC, can …

Hydrodesulfurization Of Dibenzothiophene Using Comos2, Jacob S. Sollner

Theses and Dissertations

The hydrodesulphurization (HDS) of crude oils is an important industrial process to remove sulfur from fuels. In this study, DBT was used as a model compound to study the removal of sulfur from a decahydronaphthalene solution. The catalyst was synthesized through low pressure pathways in the absence of H2S. All the synthesized catalyst were investigated using a combination of SEM, RAMAN spectroscopy, and XRD. The materials were studied for their ability to remove DBT from solution and the reaction products were analyzed. It was observed that the major reaction pathway was the direct desulphurization pathway and zero order reaction kinetics …

Synthesis Of Two Monomers For Proton Exchange Membrane Fuel Cells (Pemfcs), Abdulmajeed A. Alayyaf

Electronic Theses and Dissertations

The overall goal of this research is to synthesize two different monomers for proton exchange membrane (PEM) Fuel Cells. Such monomers are proposed to be polymerized to improve the efficiency and compatibility of electrodes and electrolytes in PEM fuel cells.

The first target is to synthesize 4-diazonium-3-fluoro PFSI zwitterionic monomer. Three steps were carried out in the lab. First one was the ammonolysis of 3-fluoro-4-nitrobenzenesulfonyl chloride. Second reaction was the bromination of Nafion monomer. The next coupling reaction, between brominated Nafion monomer and the 3-fluoro-4-nitrobenzenesulfonamide, was failed. The obstacles involve the harsh reaction condition and troublesome purification procedure.

The second …

Computational Studies Of Spin Trapping Of Biologically Relevant Radicals By New Heteroaryl Nitrones, Eyram Asempa

Electronic Theses and Dissertations

Heteroaryl nitrone spin traps have been suggested to act as free radical scavengers. The geometry optimizations and the single-point energies of the spin trapping reactions of the heteroaryl nitrones, 5,5-dimethylpyrroline-N-oxide (DMPO) and α-phenyl-N-t-butylnitrone (PBN) have been computationally studied using ab initio (Hartree-Fock (HF) and second-order Møller-Plesset (MP2)) methods and Density Functional Theory (DFT) methods. The effects of new heteroaryl substituents on a parent nitrone spin trap have been examined at the HF and MP2 levels with the 6-31G*, and cc-pVnZ (n=D, T, Q) basis sets. The thermodynamics of the spin trapping at the C-site and O-site with •H, …

Synthesis Of Diazonium (Perfluoroalkyl) Arylsulfonimide Monomers From Perfluoro (3-Oxapent-4-Ene) Sulfonyl Fluoride For Proton Exchange Membrane Fuel Cell, Faisal Ibrahim

Electronic Theses and Dissertations

Two diazonium perfluoroalkyl arylsulfonimide (PFSI) zwitterionic monomers, 4-diazonium perfluoro(3-oxapent-4-ene)benzenesulfonimide (I) and 4-(trifluoromethyl)-2-diazonium perfluoro(3-oxapent-4-ene)benzenesulfonimide (II) have been synthesized from perfluoro(3-oxapent-4-ene) sulfonyl fluoride (POPF) for proton exchange membrane fuel cells. PFSI polymers are proposed as new electrolytes due to their better thermal stability, inertness to electrochemical conditions, and lower susceptibility to oxidative degradation and dehydration. For a better integration between the electrode and the electrolyte, the PFSI polymers are expected to be grafted onto the carbon electrode via the diazonium moiety.

All the reaction intermediates and the final product were characterized with 1H NMR, 19F NMR and IR …

Direct Dissolution And Electrochemical Investigation Of Cerium And Uranium In Ionic Liquid, Janelle Droessler

UNLV Theses, Dissertations, Professional Papers, and Capstones

The solubility, coordination and speciation of f-elements in ionic liquids (ILs) has been the focus of numerous studies because the purely ionic systems have unique physical properties that can be exploited in comparison to aqueous, organic, or molten salt systems. Ionic liquids are thermally stable, have negligible vapor pressure, and are electrochemically stable at negative potentials that encompass the reduction potential of actinide species. Literature has suggested that the properties of ILs could potentially be utilized in the nuclear fuel cycle for separations and reprocessing. However, the solubility of f-elements in ILs has been significantly lower compared to traditional solvents. …

Chemoselective Reactions And Their Applications In Metabolite Isolation And Analysis., Sadakatali Shokatali Gori

Electronic Theses and Dissertations

Chemoselectivity is the preferential reaction of a reagent with a select functional group among other plausible reactions. This dissertation describes chemoselective reagents and methods explored to develop more accurate, efficient and high-throughput means to quantify metabolites containing either thiol, carboxylic acid or 1,2-diol moieties directly from biological mixtures. Chapter 1 discusses how dysregulation of thiol- or carboxylic acid-containing metabolites is either the cause or effect of cellular dysfunction. Quantifying such metabolites is important in discovery of pathways to understand etiology of diseases. Chapter 1 also discusses the need for sustainable syntheses using renewable resources and describes the traditional methods for …

Increasing Solubility Of Active Pharmaceutical Ingredients In Topical Creams Using Soluplus®, Roni Balzam

Graduate Theses/Dissertations

More than 40% of new chemicals developed in the pharmaceutical industry have poor solubility in aqueous solutions. Active Pharmaceutical ingredients (API) cannot reach their molecular targets in the body if the drug remains undissolved in the gastrointestinal system. One way to approach this problem is by using solubilizing agents. One such agent is a thermo-responsive, tri-block co-polymer which is marketed as “Soluplus®" (SP) by BASF Corporation. A part of this project is to thoroughly characterize various phase properties of SP such as cloud points and gel points temperatures. In current application, SP was incorporated into the creams formulations as an …

Electrochemical Studies Of Copolymers Of 3- Phenyl[5]Ferrocenophane-1,5-Dimethylene And Various Para-Substituted N-Phenylmaleimides, Henry Marshall Thomas

Electronic Theses & Dissertations

Ferrocene is an organometallic compound that consists of an iron atom sandwiched between two cyclopentadienyl rings. It has well understood redox properties and has been extensively studied making it useful in electrical systems. In this research alternating copolymers were synthesized via free radical polymerization from 3-phenyl[5]ferrocenophane-1,5-dimethylene and various para-substituted N-phenylmaleimides. Copolymers between this ferrocenophane and N-substituted maleimides have shown interesting electrical properties and the potential for charge transfer interactions between ferrocene and maleimide moieties. In this work, four new polymers were synthesized with differing electron withdrawing or donating groups on the para-position of the N-phenylmaleimide in order to influence potential …

Biosensors Derived From Copolymers Of Vinylferrocene With Various Para Substituted Phenylmaleimides, Nawrah Fahad Alghamdi

Electronic Theses & Dissertations

Five copolymers were synthesized from vinylferrocene with N-(4-

methoxyphenyl)maleimide, N-(4-methylphenyl)maleimide, N-phenylmaleimide, N-

(4-acetylphenyl)maleimide, and N-(4-cyanophenyl)maleimide. The resulting

copolymers were characterized by gel permeation chromatography, IR spectroscopy

and NMR spectroscopy. Thermal characterization of the copolymers included DSC

and TGA. The copolymers were also characterized electrochemically by cyclic

voltammetry in methylene chloride solutions and as a thin film in aqueous

electrolytes. As a thin film, each copolymer showed changes in oxidation potential

with different electrolytes (NaCl, NaNO3, NaClO4, and Na2SO4). These materials

were also tested as biosensors for hydrogen peroxide and dopamine, and compared to

polyvinyl ferrocene. Each material exhibited similar sensitivity …

Electrospun Nanofibers Of Metal Oxides For Energy Storage Applications, Sara Alkhalaf

Electronic Theses & Dissertations

Super capacitors are considered the most prominent and efficient energy storage devices, next to lithium ion batteries due to their high power densities, fast charge-discharge capabilities and long cyclibility. Super capacitors possess high power density in comparison to batteries and these are able to solve the increasing demand for energy in small consumer products, electrical vehicles and devices where quick power delivery is highly desired. Super capacitors are classified into two categories based on their charge storage mechanism. The first group capacitors are called electrical double-layer capacitors (EDLCs), where the charge is stored at the interface. The second group is …

Effect Of Surfactant On Structural And Electrochemical Properties Of Nickel Oxide, Muidh Albalawi

Electronic Theses & Dissertations

Today, the increasing demand for energy in the world has led to a focus on efficient and low cost energy storage devices. Many essential energy sources take a significant number of forms, including atomic energy and conventional sources, such as petroleum, coal and natural gas. Recently, super-capacitors have attracted research due to their high power densities, quick charge-discharge and long life cycles. The objective of this thesis is to alter the morphological structure of nickel oxide (NiO) utilizing different surfactants and furthermore to analyze the impact of these surfactants on the electrochemical properties of the nickel oxide. The unlimited applications …

Understanding The Optical Properties Of Ambient Sub-And Supermicron Particulate Matter: Results From The Cares 2010 Field Study In Northern California, Christopher D. Cappa, Katheryn R. Kolesar, Xiaolu Zhang, Dean B. Atkinson, Mikhail S. Pekour, Rahul A. Zaveri, Alla Zelenyuk, Qi Zhang

Chemistry Faculty Publications and Presentations

Measurements of the optical properties (absorption, scattering and extinction) of PM1, PM2.5 and PM10 made at two sites around Sacramento, CA, during the June 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are reported. These observations are used to establish relationships between various intensive optical properties and to derive information about the dependence of the optical properties on photochemical aging and sources. Supermicron particles contributed substantially to the total light scattering at both sites, about 50 % on average. A strong, linear relationship is observed between the scattering Ångström exponent for PM10 and the fraction of the scattering that is …

Facilitating Conceptual Learning In Quantitative Chemistry, Sarah R. Johnson

Electronic Theses and Dissertations

Traditional chemistry laboratory courses have a manual consisting of “step-by-step” experiments; instructions are given to complete experiments, requiring minimal information/concepts processing to be successful. This experience leaves students unprepared for the real-world, where critical thinking skills are needed to conduct research. This study focused on building analytical techniques, conceptual knowledge, and critical thinking skills used to solve research problems. A new quantitative chemistry laboratory manual was developed to transition students from traditional to inquiry-based experiments, requiring analytical method development. Data showed students having less difficulty using the new manual (0.8281 average difficulty) on method development exam questions and experiments, compared …

Ultrasound Assisted One-Pot Synthesis Of Benzo-Fused Indole-4, 9-Dinones From 1,4-Naphthoquinone And Α-Aminoacetals, Quang H. Luu, Jorge D. Guerra, Cecilio M. Castañeda, Manuel A. Martinez, Jong Saunders, Benjamin A. Garcia, Brenda V. Gonzales, Anushritha R. Aidunuthula, Shizue Mito

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

A one-pot synthesis of benzo[f]indole-4,9-diones from 1,4-naphthoquinone with α-aminoacetals has been developed. This method provides a straightforward synthesis of benzo[f]indole-4,9-diones via intramolecular nucleophilic attack of aminoquinones to aldehydes under mild reaction conditions. The detailed mechanism was also investigated.

Strategic Molecular Design To Engineer The Electron Affinity Of Self-Assembling Organic Semiconductors, Kelly Nicole Zaugg

UNLV Theses, Dissertations, Professional Papers, and Capstones

Development of electron-accepting (n-type) semiconductors used in organic photovoltaic cells and field effect transistors has been an area of research with less advancement compared to their electron-donating (p-type) counterparts. Currently, the highest performing n-type semiconductor is a fullerene-based derivative (PCBM) with a favorable ELUMO of -4.08 eV. However, PCBM has limited absorption in the visible region and fixed electron affinity. This work focuses on the development of self-assembling n-type materials with controllable electronic properties by strategically lowering ELUMO to a level comparable to PCBM. Molecular design follows an acceptor-acceptor'-acceptor (A-A'-A) configuration; with A being two 2,3-dioctyloxyphenazine substituents connected to A’ …

Computational Studies Of Microscopic Superfluidity In 4he Clusters, Angeline R. Wairegi

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The onset of microscopic superfluidity has been reported in ultracold droplets of bosons (⁴He atoms or para-H₂ molecules) containing a variety of molecular dopants. The physics of these droplets involve both Bose-Einstein condensation (BEC) and superfluidity. The two phenomena, while closely related, are not exactly the same. Superfluidity is fundamentally a microscopic effect and thermodynamic limit is necessary; it is still remarkable, though, that the signature of superfluidity has been reported in doped droplets consisting of as few as 4 ⁴He atoms. The studies presented here adopt a molecular vantage point to investigate the quantum mechanics …

Quantum Mechanical Studies Of Charge Assisted Hydrogen And Halogen Bonds, Binod Nepal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Like cement bridges one brick to another, noncovalent forces also bridge two or more molecules together to form a molecular crystal or molecular cluster. Although weaker than the covalent bond, the existence of noncovalent forces can be seen everywhere from liquid water to construction of complex biomolecules like DNA, RNA, proteins etc. An introduction of suitable charge; positive or negative, on the binding units can increase the strength of noncovalent interaction by several orders of magnitude. The primary aim of this dissertation is to explore some fundamental properties of such charge assisted noncovalent interactions which will be helpful for the …

Heterogeneous And Homogeneous Nickel-Based Electrocatalysts For Oxygen Evolution And Carbon Dioxide Reduction, Meili Sheng

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The growing global energy demand and the increasing concentration of CO₂ in the atmosphere have encouraged the development of renewable energy to replace carbon-based fossil fuels. Electrocatalytic water splitting to form H₂ and O₂ and reduction of CO₂ to CO are appealing processes and we can be directly utilize H₂ and CO as fuels or commodity chemicals in mature industrial processes, which will not alter the current carbon cycle. However, the O₂ evolution reaction of water splitting is a reaction of four-proton and four-electron transfer process, whose kinetics is very sluggish under normal conditions. …

Development Of Electrochemical Sensors Suitable For In Vivo Detection For Neurotransmitters, Mengjia Hu

Graduate Theses and Dissertations

The electrochemical method of redox cycling was exploited to achieve new discoveries in neurotransmitter detection and to advance its suitability toward in vivo use. Redox cycling has advantages in signal amplification, selectivity of species based on their electrochemical reaction mechanisms, and limited or no background subtraction. Distinction of dopamine from norepinephrine in a mixture with an electrochemical method at unmodified electrodes was demonstrated for the first time in vitro. This ability resulted from a series of fundamental studies of redox cycling behavior of the catecholamines (dopamine, norepinephrine and epinephrine) using different electrode configurations. Taking advantage of the ECC’ mechanism associated …

Structural Insights Into The Regulation Of Electron Transfer In Nitrogenase, And Modulating The Reactivity Of The Isolated Iron Molybdenum Cofactor, Andrew J. Rasmussen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

One of the most important scientific advances in the last century was the Haber-Bosch process, the industrial process of fixing nitrogen from the atmosphere to ammonia. This allowed for the commercial production and sale of nitrogen for important uses such as fertilizer for farming. The Haber-Bosch process is partially credited with the population boom that has been seen in the last century and has greatly increased the standard of living in the developed world today. While this was a great scientific breakthrough, the cost of producing the required ammonia is high, and roughly 2% of worldwide energy is used annually …

Synthesis, Structure-Activity Relationship Study, And Mode Of Action Study Of 1,4-Naphthoquinone Based Anticancer And Antimicrobial Agents, Jaya P. Shrestha

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The first three projects involve the synthesis and the mode of action study of 1,4-naphthoquinone based anticancer agents. These anticancer agents are highly potent against a wide range of cancer cell lines. These compounds showed ~8-fold selectivity towards the lung cancer cell line than the normal cell line. We also studied the mode of action and observed that generation of reactive oxygen species is the primary mode of action.

The final project involves the synthesis of multi-cationic antimicrobial agents. These compounds are active against both bacteria and fungi. These compounds are very easy to synthesize and can be scaled up …

Fluorescent Probes To Investigate Homologous Recombination Dynamics, Eric Parker Davenport

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

As the average cell’s DNA undergoes roughly 1 million molecular lesions per day, learning about one of the repair mechanisms which fixes damaged DNA is a worthwhile endeavor. Such work may provide insights into how to treat or prevent diseases such as cancers and associated genetic disorders. Homologous recombination (HR) is one pathway which is used by cells to repair a specific type of DNA damage, double-strand breaks. While HR is a complex process involving over 25 different proteins, exactly how HR works, including its regulation, is largely unknown. One protein in particular, Rad51, forms a filament on the damaged …

Oxidative Carbon-Carbon Bond Cleavage Reactions Of Metal Flavonolato And Chlorodiketonate Complexes, Sushma L. Saraf

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The research presented in this dissertation focuses on the oxidative cleavage of chemical bonds between two carbon atoms. This type of reactivity is of significant interest due to its potential application toward the development of ways to convert chemical feed stock into useful products such as pharmaceuticals, polymers and fuels in an environmentally benign and cost-efficient manner. Reactions that cleave specific carbon-carbon bonds, are catalyzed by earth-abundant metals, and involve O₂ as the terminal oxidant, are of particular interest.

Our strategy has been to study the oxidative carbon-carbon bond cleavage reactivity of metal complexes containing components similar to structures …

Atp Usage In The Dark-Operative Protochlorophyllide Oxidoreductase, Mark S. Soffe

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Chlorophylls are essential pigment molecules that function in photosynthesis, and serve to aid in utilizing energy from sunlight to power cellular processes in plants, and other organisms. To make chlorophyll, photosynthetic organisms devote an abundance of resources and energy to ensure their appropriate construction. This process of making chlorophylls is highlighted by the penultimate step in the pathway—the conversion of protochlorophyllide (Pchlide) to chlorophyllide a (Chlide).

This conversion can be mediated in two different ways, depending on the type of organism. The first method incorporates the use of a light-activated system called the light-dependent protochlorophyllide oxidoreductase (LPOR). This system, as …

Computational Chemistry Of Non-Covalent Interaction And Its Application In Chemical Catalysis, Vincent De Paul Nzuwah Nziko

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Known to be weaker than conventional covalent bonds, non-covalent bonds, especially hydrogen bond, has shown to be of great importance in molecular structures such as DNA, RNA, proteins and other organic frameworks. In this dissertation, we looked at non-covalent interactions other than the hydrogen bond. Replacement of the bridging hydrogen atom in a typical hydrogen bond by other atoms such a halogen, chalcogen and tetrel lead to the formation of interactions which are comparable in strength to the hydrogen bond. Unlike the hydrogen bond which arises mainly from electrostatics, these unconventional interactions mostly result from induction. Besides studying the fundamentals …

The Use Of Isomeric Testosterone Dimers To Explore Allosteric Effects In Substrate Binding To Cytochrome P450 Cyp3a4, Ilia G. Denisov, Piotr J. Mak, Yelena V. Grinkova, Dominic Bastien, Gervais Bérubé, Stephen G. Sligar, James R. Kincaid

Chemistry Faculty Research and Publications

Abstract: Cytochrome P450 CYP3A4 is the main drug-metabolizing enzyme in the human liver, being responsible for oxidation of 50% of all pharmaceuticals metabolized by human P450 enzymes. Possessing a large substrate binding pocket, it can simultaneously bind several substrate molecules and often exhibits a complex pattern of drug–drug interactions. In order to better understand structural and functional aspects of binding of multiple substrate molecules to CYP3A4 we used resonance Raman and UV–VIS spectroscopy to document the effects of binding of synthetic testosterone dimers of different configurations, cis-TST₂ and trans-TST₂. We directly demonstrate that the binding …

Lipid Content And Biomass Analysis In Autotrophic And Heterotrophic Algal Species, Addie M. Lauder, Daniel P. Jones, Thomas E. Walker, Todd Allen

Montview Journal of Research & Scholarship

Biofuels are a form of renewable energy derived from living matter, typically plants. The push for biofuels began in order to decrease the amount of carbon dioxide (CO2) released into the atmosphere, as biofuels are essentially carbon neutral. The idea is the same amount of CO2 the plants took in to perform photosynthesis will then be released in the burning of the biofuels. Algae is an excellent source of biofuels because it grows quickly and is versatile in terms of the type of fuel it can produce. The two most common mechanisms for algae growth are heterotrophic or photoautotrophic. Heterotrophically …

H-Bonding And Stacking Interactions Between Chloroquine And Temozolomide, Okuma Emile Kasende, Vincent De Paul Nzuwah-Nziko, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The interactions between temozolomide and chloroquine were examined via Dispersion-Corrected Density Functional Theory and MP2 methods. Chloroquine was considered in both its lowest energy structure and in a local minimum where its aromatic system and secondary amine group are free to interact directly with temozolomide. The accessibility of these two components to intermolecular interaction makes the lowest energy dimer of this local monomer minimum competitive in total energy with that involving chloroquine’s most stable monomer geometry. In either case, the most stable heterodimer places the aromatic ring systems of the two molecules parallel and directly above one another in a …

Ph Dependence Of The Spectral Distribution Of Hydrogen Peroxide Quantum Yields, Juliana R. Laszakovits

Departmental Honors & Graduate Capstone Projects

Dissolved natural organic matter (DOM) is an important natural photosensitizer, which produces a variety of reactive oxygen species including singlet oxygen, hydroxyl radical, superoxide (O2-) and hydrogen peroxide (H2O2). H2O2 is formed primarily through the dismutation of O2-. Previous work has suggested that neither singlet oxygen nor excited triplet states of DOM are responsible for H2O2 production. Rather, reducing DOM intermediates likely form O2-, which in turn produce H2O2. One such intermediate may be a charge-separated DOM species (DOM+/-) formed by charge transfer (CT) relaxation of excited singlet states. In the CT model, the electron transfer is believed to occur …