Chemistry Commons^™

Oxadiazinones As Chiral Auxiliaries: Chiral Templates For Asymmetric Conjugate Addition In The Synthesis Of ( R )-( + )-Tolterodine, Fatima Olayemi Obe

Theses and Dissertations

The stereoselective formation of carbon-carbon bonds through the process of conjugate addition has proven to be a very important methodology in synthetic organic chemistry. In this context, oxadiazinones are chiral auxiliaries that have been applied in the asymmetric aldol addition reaction to synthesize valuable synthetic fragments such as the aldol side chain of the multi-drug resistance medicinal agent, hapalosin. This thesis describes efforts that were directed towards employing oxadiazinones as chiral scaffolds for the process of asymmetric conjugate addition with the ultimate objective of using this methodology in the preparation of medicinal agents such as Tolterodine. Preliminary efforts focused on …

Novel Reusable Renewable Resource-Based Benign Nanocomposites For Removal And Recovery Of Phosphorus From Contaminated Water, Amita Nakarmi

Theses and Dissertations

Phosphorus (P) is a pollutant which degrades water quality and is a cause of concern for eutrophication of water. This research dissertation discusses the synthesis of novel, renewable resource-based, single metallic and bimetallic nanocomposite media, their use in Phosphorus remediation as phosphate, and their regeneration for reuse. The media consist of chemically modified pine wood chips in addition to metal oxides/hydroxides. Iron is used for single metallic media, while cerium/aluminum and cerium/manganese are used for mixed bimetallic media. The synthetic method is environmentally friendly and economically viable. These nanocomposites may find use in the removal of P from contaminated waters, …

Doped Carbonaceous Materials And Thin Films As Smart Materials For Pollutant Remediation And Electrocatalytic Applications, Bijay Paudel Chhetri

Theses and Dissertations

In this dissertation, we focused on utilizing naturally abundant, low-cost, environmentally benign, and renewable carbon precursors to synthesize doped carbonaceous materials as they are of particular interest in the scientific research because of their characteristic physiochemical properties. Such renewable bio-polymer derived doped carbonaceous hold potential applications in fuel cells, pollutant remediation, and many others. Due to the growing interest in developing high performance electrode materials for energy storage devices like supercapacitors, the design of thin-fils electrodes that delivered high specific capacitance with long term stability is essential. In chapter 1, the dissertation discussed backgrounds in carbon-based materials, renewable biopolymers, fuel …

Cellulose-Based Doped Carbon Materials For Removal Of Nitrophenols From Water, Ambar Bahadur Rangu Magar

Theses and Dissertations

Nitrophenols (NPs) and their derivatives are highly toxic, mutagenic, and bio-refractory pollutants commonly present in natural water resources and industrial wastewater. Various types of materials and methods have been practiced removing the NPs from polluted water. In this research, we are focusing on synthesizing of inexpensive doped carbon-based materials using renewable and biodegradable polymers such as microcrystalline cellulose and nanocrystalline cellulose. Current work has been undertaken to develop doped carbon-based materials using a low-cost and straightforward method and characterized using different analytical techniques. The synthesized materials were used for the sustainable and efficient removal of NPs from an aqueous environment …

Recombinant Expression Of Preptin Analogs For Alanine Scanning Mutagenesis Of Residues 27-29, Tehgan N. Anguilm

Theses and Dissertations

The novel peptide preptin consists of 34 amino acid residues corresponding to Asp⁶⁹-Leu¹⁰² of proinsulin-like growth factor E-peptide. Preptin has been isolated from pancreatic beta cells, and it has been found to exhibit both metabolic and mitogenic activities. This makes preptin an attractive candidate to treat insulin-independent diabetes and osteoporosis. Alanine scanning mutagenesis was utilized to substitute an alanine for residues Trp²⁷, Arg²⁸, and Gln²⁹ of preptin in order to ultimately study the structure-activity relationship of these residues to preptin’s metabolic activity.

Elucidating The Binding Pockect Of The Gpr119 Receptor, A Type 2 Diabetes Target, Matthew Dy Rosales

Theses and Dissertations

An in-house homology model of the GPR119 receptor was used to identify residues which may affect ligand binding and ligand-dependent activity through computational and experimental studies. In a docking study comparing an agonist and its inverse agonist structural analog, Leu5.43169, L6.52242 and Ser1.324 appear to be involved in ligand binding. These residues were mutated experimentally to test the predictions of the homology model. The in vitro studies indicate that Leu5.43169 and Ser1.324 mutations cause ten-fold and six-fold decreases in ligand-induced cAMP formation, indicating their importance in ligand-induced activation. Leu6.52242 mutations show minimal effect in cAMP production, indicating a lesser involvement …

Analysis Of Fatty Acids In Chukchi Sea Sediments, Damilola Ajadi

Theses and Dissertations

The Arctic Ocean and its marginal seas are key areas for understanding the global climate system. Climate change causes increased terrigenous materials to be carried into the ocean as well as higher production of marine organic matter in the ocean. This study determined the concentrations, distribution, and sources of fatty acids in core sediments from four locations: Stations H32, H30, BarC5 and H24 in the Chukchi Sea, which are in the Arctic Ocean. Fatty acids are valuable tracers of marine or terrigenous inputs and may give evidence to the extent of climate change. Fatty acids were analyzed, characterized using GC-MS …

Exploring Pyrochlore Host For Upconversion And Downconversion Luminescence Materials, Mitzy A. Penilla Garcia

Theses and Dissertations

Pyrochlore has been the focal point of research in materials science community in the area of nuclear waste host, thermal barrier coatings, solid oxide fuel cell, catalyst, magnetism, luminescence etc. Such application arises due to their unique properties such as wide band gap, high radiation stability, low thermal conductivity, high dialectic constant. The fact it also has high structural ability, low phono energy and ability to accommodate dopant ion at both A- site and B-site; they are considered excellent host for inorganic phosphors. Here research work is directed towards synthesizing optical materials having high quantum efficiency for down-conversion (DC) and …

Gel Permeation Chromatography Purification And Surface Chemistry Of Technologically Relevant Colloidal Quantum Dots, Adam Roberge

Theses and Dissertations

Semiconductor quantum dots have received extensive research interest due to the size tunable band gap, large extinction coefficient, and ease of synthesis. These nanocrystals possess large surface to volume ratios and the chemistry at the surface of the nanocrystal greatly influences the resultant optoelectronic properties. Therefore, after synthesis, purification of the quantum dot samples to remove synthetic by-products that may alter these properties is of great importance. Gel permeation chromatography (GPC), a form of size exclusion chromatography, has been shown to reproducibly purify CdSe quantum dots. This work focuses on the expansion of purification by gel permeation chromatography to other …

Investigating The Role Of Iron-Sulfur Signaling In Yeast Transcriptional Regulation, Malini Gupta

Theses and Dissertations

As an essential cofactor in a myriad of cellular processes, uptake and mobilization of iron must be tightly controlled. Iron homeostasis in fungi involves balancing iron uptake and storage with iron utilization to achieve adequate, non-toxic levels of this essential nutrient. Extensive work in the non-pathogenic yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe have uncovered unique iron regulation networks for each organism that control iron metabolism via distinct molecular mechanisms. The activities of all fungal iron-sensing transcription factors characterized to date are regulated via iron-sulfur cluster signaling.

In Saccharomyces cerevisiae, expression of iron uptake, utilization and storage genes is primarily regulated …

Mechanistic Investigations Of Isothiourea Catalyzed Silylations Of Secondary Alcohols Using Reaction Progress Kinetic Analysis, Brandon Kane Redden

Theses and Dissertations

The primary focus of this research is in expanding the knowledge and scope of the asymmetric silylation of alcohols. Since it was discovered in 2011 that chiral isothioureas can selectively silylate alcohols through kinetic resolution reactions, the Wiskur group has been working to increase the applications of the methodology. Understanding the kinetics behind the mechanism of the reaction is fundamental in the designing both improved kinetic resolutions and other silylation methodology. Chapter 2 focuses on using reaction progress kinetic analysis to monitor silylations of secondary alcohols with thiourea catalysts in real time using in situ IR to determine the rate …

Development Of Natural Product-Derived Cationic Polymers For Biomaterial Applications, Moumita Sharmin Jui

Theses and Dissertations

In this thesis, multicyclic natural products and metallocene-containing polymers were synthesized for biomedical applications.

Chapter 1 describes the overall background, the recent development of natural product-based antimicrobial biomaterial and metallocene containing polymer for biomedical application. Afterward, the primary research objectives of my research are illustrated.

In chapter 2, a multicyclic natural product derived guanidine-based facially amphiphilic homopolymers and copolymers were synthesized. Cholic acid is one of the bile acid derivatives used to prepare facially amphiphilic moieties. A neutral polyethylene glycol (PEG) component was used to prepare copolymers with cholic acid. Reversible-addition fragmentation chain transfer (RAFT) polymerization technique was used to …

Chemistry Of A Biscarborane Dithiol And Its Nickel (Ii) Complex, Tyler Hemingway

Theses and Dissertations

Neutral biscarborane dithiol and its anionic dithiolate form were successfully synthesized and structurally characterized. The C–C intracluster bond lengths were found to be responsive to the electron density on the cluster. Introduction of two thiol groups on biscarborane led to the significant increase of intracluster C–C bond lengths compared to those of unsubstituted biscarborane. Furthermore, the anionic dithiolate form had even longer C–C cluster bonds. This comparison shows electronic effect of substituents attached to carbon atoms of biscarborane on the strength of its C–C bonds. Additionally, a novel Ni complex was obtained using this dithiolate as a ligand. This complex …

Tailored Multifunctional Heterometallic Metal-Organic Frameworks, Otega Anthonia Ejegbavwo

Theses and Dissertations

Metal-organic frameworks (MOFs), which are well-defined and porous extended structures consisting of organic linkers connected to inorganic secondary building units, are a class of materials that have received tremendous attention over the last decade. This geometrically growing interest in MOFs is attributed to their properties of porosity, tunability, modularity, crystallinity, flexibility, and long-term stability, which makes them attractive candidates for various applications. This dissertation focuses on two major studies, the first part encompasses the strategic design, preparation, and extensive studies of actinide containing MOFs (An-MOFs). This work, presented within the first two chapters, demonstrates the effective utilization of MOF modularity …

Structural, Functional And Immunological Studies Of Group 1 And 2 House Dust Mite And Profilin Allergens For The Development Of Allergen Specific Diagnostics And Immunotherapy, Anyway B. Kapingidza

Theses and Dissertations

Group 1 and 2 house dust mites (HDM) allergens elicit IgE response in more than 80% of sensitized individuals. These allergens affect 10-30% of the world’s population. Prolonged inhalation of low doses of allergens (microgram amounts inhaled over months or years) by genetically predisposed individuals leads to the induction of a Th2-type immune response induced by allergen-specific immunoglobulin E (IgE) produced by plasma cells resulting in allergic diseases like asthma, atopic dermatitis, and rhinitis. Group 1 and 2 HDM allergens, in particular, are associated with the development of the aforementioned allergic diseases. The goal of this research was to characterize …

An Examination Between Neighborhood Characteristics And Alzheimer’S Disease And Related Dementias And Caregiver Mental Health In South Carolina, Mohammad Jahirul Islam

Theses and Dissertations

Carboranes are of topical interest due to their unique structures and applications in the fields of catalysis, polymers, material sciences and supramolecular chemistry. Icosahedral closo-dicarbadodecaboranes are remarkably robust three-dimensional boron-carbon clusters with two slightly acidic C-H bonds. Moreover, coordinatively unsaturated transition-metal complexes containing C-functionalized ortho-carborane are considered as potential catalysts for activation of small molecules.

Recently, we reported the synthesis of a pyridine-backbone pincer complex {(C₅H₃N)(C₂B₁₀H₁₀)₂}Ni(CH₃CN) (1) in which two C-functionalized ortho-carborane clusters act as the arms of the pincer ligand. The complex …

Systematic Development Of Photocatalysts, Mary Victoria Bobo

Theses and Dissertations

Photocatalysis is a rapidly growing field and a powerful synthetic tool that has recently seen many advancements, showing immense promise to replace classic catalysis with a mild and elegant alternative methodology. Visible light driven catalysis relies on redox stable transition metal and organic based photoactive catalysts (photocatalysts) that absorb visible light efficiently and facilitate electron/energy transfer. The desire for greener and more renewable catalytic methods has caused research to shifted away from traditional transition metals (due to scarcity and environmental toxicity) and toward organic based photocatalysts. Due to similar photophysical and electrochemical characteristics of each of these classes of photocatalysts …

Fundamental Studies Of Bimetallic Model Surfaces And Metal Organic Framework Thin Films, Fathima Sharfa Farzandh

Theses and Dissertations

This work is mainly focused on gaining a fundamental understanding of conventional bimetallic catalysts in order to correlate their macroscopic properties with the observed kinetic properties. This is achieved by synthesizing and studying fundamental model surface analogues of conventional catalysts that are difficult to study due to their complex, ill-defined nature. A wide array of surface science techniques that use ultra-high vacuum (UHV) conditions are readily available for detailed studies that can be conducted on model surfaces. This work focuses on the synthesis and investigation of two fundamental bimetallic catalysts formed via the addition of a second metal to an …

A Behavioral And Voltammetric Study Of The Effects Of Pb Exposure In Mice As A Model Of Autism Spectrum Disorder, Brenna Parke

Theses and Dissertations

Despite being a known toxin for several centuries, lead (Pb²⁺) is still utilized in commercial products including leaded gasoline, paint, and modern cosmetics. This presence has caused (Pb²⁺) to pollute the environment, including public drinking water sources. The recent outbreaks of elevated levels of (Pb²⁺) in the drinking water in Flint, Michigan and Washington D.C. have caused large populations to be exposed to the heavy metal for months at a time, raising a public health concern over the implications of widespread, long-term (Pb²⁺) exposure. Young children are most susceptible to the effects …

Fundamental Studies Of Bimetallic Model Surfaces And Metal Organic Framework Thin Films, Fathima Sharfa Farzandh

Theses and Dissertations

This work is mainly focused on gaining a fundamental understanding of conventional bimetallic catalysts in order to correlate their macroscopic properties with the observed kinetic properties. This is achieved by synthesizing and studying fundamental model surface analogues of conventional catalysts that are difficult to study due to their complex, ill-defined nature. A wide array of surface science techniques that use ultra-high vacuum (UHV) conditions are readily available for detailed studies that can be conducted on model surfaces. This work focuses on the synthesis and investigation of two fundamental bimetallic catalysts formed via the addition of a second metal to an …

Electrochemical Nitrogen Reduction To Ammonia Using Molybdenum Disulfide-Based Nanocatalysts, Assem Omar M Basurrah

Theses and Dissertations

Ammonia is the basis for producing fertilizers for food production. The Haber-Bosch process is the main method to produce ammonia. Because of the energy and environmental problems associated with the Haber-Bosch process, extensive research is being explored for other ammonia production methods, including electrochemical methods based on nitrogen reduction reaction (NRR). In this thesis, molybdenum disulfide nanocatalysts (~4 nm) on carbon fibers were synthesized by hydrothermal reactions. The resulting composites were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrochemical properties of the composites were measured by using linear sweep voltammetry, cyclic voltammetry, and controlled potential …

An Assessment Of The Spatial Variation Of Isotopic Ratios In A Candu-6 Reactor For Nuclear Treaty Monitoring, Aaron W. Burkhardt

Theses and Dissertations

The Preparatory Commission for the Comprehensive Nuclear Test Ban Treaty Organization developed the International Monitoring System for monitoring for nuclear explosive testing and compliance with nuclear treaties. Many of the International Monitoring System stations are capable of detecting radionuclides that can be used to determine their origin and creation environment. However, there is not a single unique signature associated with each creation environment. Nuclear reactors, for example, can have a wide range of isotopic concentrations caused by spatial variations in neutron flux intensity and energy. As a single sample only provides a single isotopic measurement, this can make disambiguation difficult …

A Machine Learning Approach To Characterizing Particle Morphology In Nuclear Forensics, Daniel A. Gum

Theses and Dissertations

A machine learning approach is taken to characterizing a group of synthetic uranium bearing particles. SEM images of these lab-created particles were converted into a binary representation that captured morphological features in accordance with a guide established by Los Alamos National Laboratory. Each particle in the dataset contains an association with chemical creation conditions: processing method, precipitation temperature and pH, calcination temperature are most closely tied to particle morphology. Additionally, trained classifiers are able to relate final products between particles, implying that morphological features are shared between particles with similar composition.

Analysis Of Organochlorine Pesticides Levels In Irrigation Water From Various Water Sources Across Egypt, Omar Tarek Khairy

Theses and Dissertations

Organochlorine pesticides are extensively used in agriculture to cope with the world’s increasing population and demands for nutrition. This class of pesticides poses a serious risk to human health upon chronic exposure to elevated levels. Determination of organochlorine pesticides levels in water has been extensively covered in literature in Egypt and other parts of the world. The need for up-to date data and statistical information regarding the levels of organochlorine pesticides in water is ever increasing. These compounds, although a lot have been prohibited from use decades ago, can still be detected in trace levels in water due to their …

Chemical Synthesis And Biological Evaluation Of Benzimidazoles As Chemotherapeutics, Leonard Barasa

Theses and Dissertations

Nitrogen-containing heterocycles are among the most important structural motifs of chemical substances, which are well represented among natural products, and pharmaceuticals. The presence of nitrogen in heterocycles help to modulates physicochemical properties and the pKa profile of therapeutic leads.

Benzimidazole is a heterocyclic structure and a privileged scaffold that is routinely used during drug discovery efforts. The benzimidazole scaffold has structural similarity to purine which makes it a useful structural motif for the development of pharmaceutical or biological interesting molecules. Benzimidazole derivatives possess a wide variety of biological activities, including anti-bacterial, anti-cancer, and anti-inflammatory activities. Development of synthetic methods to …

Development Of Supported Pd-Based Catalysts For Carbon-Carbon Cross-Coupling And Oxidation Reactions, Mrinmoy Das

Theses and Dissertations

Heterogeneous catalysts are a crucial part of chemistry used for various chemical synthesis stages, pharmaceutical, and environmental applications. The use of nanoparticles or rather nanocatalysts enhances the heterogeneous catalytic applications. Both chemical and physical methods can be used to synthesize nanocatalysts. Chemical synthesis methods require comparatively fewer instruments and can easily synthesize a large amount of nanocatalysts. Nevertheless, chemical synthesis methods require reducing agents and solvents that can be toxic or harmful materials. They often need harsh reaction conditions as well, like high temperature and pressure. On the other hand, physical synthesis methods often require complex instrument setup, but their …

Discerning The Spectroscopic Properties And Chemical Reactivity Of Bioinspired Metallocomplexes, Ashley K. Forney

Theses and Dissertations

In Nature, metalloenzymes catalyze a variety of thermodynamically demanding reactions with remarkable performance under mild, physiological conditions. This innate ability is a driving force for the development of nature inspired, synthetic analogues that are robust and can catalyze a variety of organic transformations. This work involves the successful syntheses of four coordinate, bioinspired complexes, [M^II(n-DOB)] (M = Ni, Co, and Cu; n = 12 and 13), which have been characterized by NMR, ESI-MS, UV/Vis, EPR, and CV. Spectroscopic evidence presents the generation of reactive metal-(di)oxygen species that display amphoteric reaction behavior, making these rarities among inorganic oxidants. These …

Detection Of Biomolecules Via Ocp Measurements Using Npg Electrodes, Borkat Ullah

Theses and Dissertations

In sensing application nanoporous gold (NPG) has attracted much attention. NPG is prepared by dealloying Au:Ag alloys. Characterization was done using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV). In this work, the open circuit potential (OCP) of ferricyanide, cysteine, uric acid, and ascorbic acid was measured in phosphate buffer solution (PBS) and biofouling solution containing bovine serum albumin (BSA) at pH 7.4. OCP measurement has been hindered due to biofouling and surface passivation on the metal electrodes. By the use of the NPG electrodes, electrochemical activity can be maintained. From the OCP measurement of cysteine, …

Redox-Active Porous Organic Materials For Electrochemical Energy Storage Applications, K. Shamara Weeraratne

Theses and Dissertations

As the demand for renewable energy technologies grows, so does the need for cheaper, more efficient rechargeable batteries to store the energy. While lithium-ion battery (LIBs) technology is well established, it suffers from limited lithium supplies. Furthermore, the highly toxic transition metals used in the electrodes places a huge burden on the environment. Therefore, replacing lithium with more economical sodium metal in rechargeable batteries (i.e. sodium-ion batteries, SIBs) has garnered considerable attention. Despite the fact that sodium and lithium share similar electrochemical properties, which may cause the transition from lithium to sodium easier, the larger ionic radius of Na^{+ …}

Solid Phase Extraction And High-Precision Mass Spectrometry Analysis Methods For Crassostrea Virginica Metabolome, Alyssa Darling

Theses and Dissertations

Metabolomics is the rapidly-growing field which focuses on the endpoints of biological processes, and has the capability to provide a snapshot of an organisms’ interaction with their environment on a molecular scale. The objective of the experiment herein was to develop a standard metabolic extraction technique coupled with ultrahigh-precision analytical tools to build a global metabolic pathway of the keystone species Crassostrea virginica. To achieve this, C. virginica whole-body samples were extracted using acetonitrile and methanol, then split into a dehydrated group and a diluted group. Following reversed-phase solid phase extraction (RP-SPE) of both groups, metabolites were identified using …