Chemistry Commons^™

Studies Of The Preparation Of Pi-Extended Anthracenes And Their Reactivity With An Emphasis On Their Photoreactivity, Hasnaa Abdelkareem Sadeq

Theses

Both 9,10-diaryl and 9,10-diarylethenyl substituted Anthracenes have recently been forwarded as light-regulated semiconducting materials, as well as potential constituent molecules in light-harvesting devices for the organic solar cell applications. So, it is of importance to understand whether such 9,10-substituted Anthracenes are stable under photo-irradiation for a long time, and what type of reactions they could undergo. In the present thesis, photochemistry of 9-anthranylacrylates and 9-aroylethenylanthracenes has been investigated. Anthranylacrylates and 9-aroylethenylanthracenes have been prepared by Wittig-olefination reaction from 9-anthranylcarbaldehyde. Bromination of these molecules was found to give an access to 10-aryl-9-aroylethenylanthracenes after Suzuki-Miyaura coupling reactions. While 9-ethenyl-substituted Anthracenes in principle …

Applications Of Pure And Recycled Polymeric Micronanofiber For The Removal Of Oil Spills, Afra Gharib Khamis Al-Blooshi Al-Blooshi

Theses

Cleaning oil spills is a universal concern due to its environmental impact. The aim of this study is to study the effectiveness and applications of pure and recycled polymers in clean-up and the recovery of crude oil from oil spills. In this study, micro-nanofibers of analytical-grade and commercial polystyrene samples were prepared by electrospinning technique. Fiber size distribution was shown to vary with the electrospinning parameters and type of polymer. Fibrous sorbents prepare hereafter were investigated for their efficiency in removing oil spills. Results showed a variation in the sorption capacities of the fibers to various types of crude oils …

Applications Of Pure And Recycled Polymeric Micro-Nanofiber For The Removal Of Oil Spills., Afra Gharib Khamis Al Blooshi

Theses

Cleaning oil spills is a universal concern due to its environmental impact. The aim of this study is to study the effectiveness and applications of pure and recycled polymers in clean-up and the recovery of crude oil from oil spills. In this study, micro-nanofibres of analytical-grade and commercial polystyrene samples were prepared by electrospinning technique. Fiber size distribution was shown to vary with the electrospinning parameters and type of polymer. Fibrous sorbents prepared hereafter were investigated for their efficiency in removing oil spill. Results showed variation in the sorption capacities of the fibers to various types of crude oils with …

Chromatographic Analysis Of Drug-Protein Interactions During Diabetes And Characterization Of Human Serum Albumin Through Multidimensional Mass Spectrometry, Ryan E. Matsuda

Department of Chemistry: Dissertations, Theses, and Student Research

Diabetes is a metabolic disease that can lead to the non-enzymatic glycation of serum proteins such as human serum albumin (HSA). Previous studies have indicated that glycation can affect the structure and function of these proteins. This dissertation describes the development of tools and techniques based on high performance affinity chromatography (HPAC) and multidimensional mass spectrometry to analyze the effects of glycation on the function and structure of HSA.

A major portion of this research involved the utilization of HPAC to examine the effect of glycation on the binding of three second-generation sulfonylurea drugs and one third-generation sulfonylurea drug. These …

Molecular Mechanism For The Biosynthesis Of Antifungal Hsaf And Antibacterial Wap-8294a2, Haotong Chen

Department of Chemistry: Dissertations, Theses, and Student Research

Bioactive natural products are a major source of anti-infectives. Many ubiquitous inhabitants of soil and water, such as the Gram-negative, prolific producers of natural products, Lysobacter, remain largely unexplored. This PhD thesis reports our studies of the biosynthetic mechanism for a novel antifungal natural product HSAF and a potent anti-MRSA natural product WAP-8294A2.

In the first chapter, we give a short review of the biosynthesis of polyketides, focusing on those which exhibit new biosynthetic features. In subsequent chapters, we present original research on the biosynthetic mechanisms of dihydromaltophilin, a heat stable antifungal factor (HSAF). HSAF is the main antifungal …

Computational Prediction And Rational Design Of Novel Clusters, Nanoparticles, And Solid State Materials, Alexander S. Ivanov

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The prediction of structure at the atomic level is one of the most fundamental challenges in materials science. Indeed, the structure is arguably the most important piece of information about a material, as it determines pretty much all properties of a material. Knowing the structure, one can analyze a large number of properties of a material, even before it is synthesized – the crucial importance of structure prediction for computational molecular design. This dissertation describes the technique of reliable theoretical predictions and presents the results on the successfully predicted unusual clusters, nanoparticles and solid state materials. The major part of …

Facile Synthesis And Electrochemical Analysis Of Cobalt Sulfide Nanostructures For Supercapacitor Applications, Esam Alqurashi

Electronic Theses & Dissertations

The main objective of the thesis is to understand the effect of morphologies and electrolytes on the electrochemical properties of cobalt sulfides. The nanostructured cobalt sulfides were synthesized by a facile hydrothermal method. For this, cobalt nitrate Co(NO3)2.H2O, cetyl trimethylammonium bromide (CTAB), thioacetamide (TTA), poly (vinyl pyrrolidone) (PVP) and ethylene glycol were used. The effect of growth parameters such as solvent and presence of surfactants on the size and morphology of the cobalt sulfides were investigated. It was observed that these variations could provide cobalt sulfides with a range of sizes, shapes and morphologies. The nanostructured cobalt sulfides were structurally …

Aqueous Raft Polymerization Of Glycopolymers For Peptide Interaction Studies And Antimicrobial Peptide Mimics For Antimicrobial Activity And Selectivity Studies, Sarah Elizabeth Exley

Dissertations

The first section of this work describes the synthesis and characterization of novel glycopolymers synthesized to model GM1 gangliosides, a glycolipid found in neuronal cells. Glucose and galactose were attached to N-hydroxyethyl acrylamide, using chemistry that granted control over the stereochemistry at the C1’ carbon of each saccharide, and polymerized via aqueous RAFT (aRAFT). Homopolymers, targeting either 30 or 300 DP, and copolymers, with N-dimethyl acrylamide, were prepared as a glycopolymer platform for investigation of amyloid β (Aβ), a naturally occurring peptide associated with Alzheimer’s disease, aggregation. Aβ aggregation kinetics and aggregate size in the presence of glycopolymer were determined. …

Removal Of Cobalt And Nickel From Water Using Mno2 And Mn3o4 Nanomaterials, Maria Dolores Pacheco

Theses and Dissertations - UTB/UTPA

Nanomaterials MnO2 and Mn3O4 were synthesized using a titration/precipitation technique and characterized with powder XRD. A pH assay determined the optimum binding for cobalt and nickel occurred at pH 5 for both nanomaterials. A time dependency study determined that cobalt and nickel required more time with MnO2 for maximum adsorption than Mn3O4. The binding capacity study showed cobalt and nickel have good binding capacity with both nanomaterials. Interfering ion assay in the presence of Na+ , Ca2+ and Mg2+ showed minimal difference in the adsorption of cobalt and nickel to MnO2 or Mn3O4. Cobalt and nickel showed a reduction in …

Analysis Of Free Solute Fractions And Solute-Protein Interactions Using Ultrafast Affinity Extraction And Affinity Microcolumns, Xiwei Zheng

Department of Chemistry: Dissertations, Theses, and Student Research

This dissertation describes the use of a high-performance affinity chromatography method based on ultrafast affinity extraction and microcolumns to study biological interactions.

In the first project, a new method was created and based on ultrafast affinity extraction to determine both the dissociation rate constants (k_d) and association equilibrium constants (K_a) for drug-protein interactions in solution. Various conditions to optimize the use of ultrafast affinity extraction for equilibrium and kinetic studies were considered.

The objective of the next portion of this dissertation was to develop a chromatographic approach to measure free drug fractions in more …

Investigations Into The Molecular Mechanisms Of Bacterial Pathogen-Host Interactions: Construction Of A Dual Plasmid System For Incorporation Of Unnatural Amino Acids Into Pseudomonas Syringae Pv. Tomato Dc3000, Scotty D. Raber

Department of Chemistry: Dissertations, Theses, and Student Research

A dual plasmid system for the incorporation of unnatural amino acids into plant pathogen, Pseudomonas syringae pv. tomato DC3000, has been designed. This invention is expected to allow (a) mutations of proteins synthesized by the bacterium, P. syringae pv. tomato DC3000, that can capture molecular targets, especially for such modified proteins secreted by the phytopathogen into the host plant cells of A. thaliana and S. lycopersicum, (b) expression of biological probes in the bacterial species to monitor changes in redox, nutritional, and other small molecule states over pre-, post- and in situ disease stages, and (c) secretion of such …

Synthesis And Characterization Of Carbonized Poly (Divinylbenzene) Microspheres For Carbon/Nanodiamond/Polymer-Based Core-Shell Materials And Applications Of This Mixed-Mode Phase To High-Performance Liquid Chromatography, Chuan-Hsi Hung

Theses and Dissertations

This work focuses on improving the quality of carbon-based core-shell materials for high performance liquid chromatography (HPLC) via the characterization of the core materials, and also the development of chromatographic methods (separations) for them. In the early part of this work, I applied organic synthesis to make uniform, spherical poly(divinylbenzene) (PDVB) microspheres, and then carbonized them to prepare carbon core materials for core-shell particle synthesis. Here, I studied in detail the surface and material properties of these particles with multiple instruments, which allowed me to describe the physical and chemical changes that took place during each treatment. The uniform, spherical …

Collectivity Of 0+ States In 160Gd, S. R. Lesher, C. Casarella, A. Aprahamian, B. P. Crider, R. Ikeyama, I. R. Marsh, Marcus T. Mcellistrem, Erin E. Peters, F. M. Prados-Estévez, M. K. Smith, Z. R. Tully, J. R. Vanhoy, Steven W. Yates

Chemistry Faculty Publications

Excited 0⁺ states in ¹⁶⁰Gd have been examined with the (n,n′γ) reaction at incident neutron energies up to 2.8 MeV. Gamma-ray excitation functions and angular distribution measurements allow the confirmation of the existence of 0⁺ states at 1379.70 keV and 1558.30 keV, but we reject the assignments of additional previously suggested 0⁺ candidates. Limits on the level lifetimes of the observed 0⁺ states permit an evaluation of the collectivity of these states.

Sulfur-Oxidation Enhances Nitrile Hydration In Bioinspired Ruthenium Complexes : Catalytic, Kinetic, And Dft Investigations., Davinder Kumar

Electronic Theses and Dissertations

The current dissertation focuses on the effects of sulfur‒oxidation on nitrile hydration activity of a series of ruthenium(II) complexes inspired by nitrile hydratase (NHase). NHase catalytically hydrates nitriles to amides at a low spin non‒heme Fe(III) or non‒corrin Co(III) metal center. The active‒site employs a N2S3X type donor set using two carboxamido nitrogens and three cofacial cysteinic sulfurs that are present in distinct oxidation states as sulfinate (RSO2¯), sulfenate (RSO¯), and thiolate (RS¯). The apical site is occupied by substrate or solvent. A lack of sulfur‒oxidation renders the enzyme inactive. Three precatalysts, LnRuPPh3 (n = 1‒3), are employed to assess …

A Study Of The Catalytic And Chemical Properties Of Palladium And Palladium-Silver Monolayer Protected Clusters., Luther Benjamin Hutcherson

Electronic Theses and Dissertations

This thesis describes a study of the ligand chemistry of Pd Monolayer-Protected Clusters (MPCs) synthesized in the presence of octylamine. MPCs consists of a metal core surrounded by various organic stabilizers. Pd MPCs coated with alkanethiols, alkylamine, dendrimers, surfactants, and polymers have recently been explored for catalysis applications.Pd MPCs coated with alkylamines are more catalytically active than alkanethiols for hydrogentation/isomerization of allyl alcohol, but at shorter chain lengths are unstable in H2. We explored Pd MPCs synthesized in the presence of octylamines and discovered that the ligands attach to Pd as octanenitrile. This amine to nitrile conversion is catalyzed by …

Mechanochemical Investigation Of A Glassy Epoxy-Amine Thermoset Subjected To Fatigue, Stephen Finley Foster

Dissertations

Covalent bonds in organic molecules can be produced, altered, and broken through various sources of energy and processes. These include photochemical, thermochemical, chemical, and mechanochemical processes. Polymeric materials derive their physical properties from the time scale of motion, summation of intermolecular forces, and number of chain entanglements and crosslinks. Glassy thermoset polymers experience mechanical fatigue during dynamic stress loading and properties diminish with inevitable material failure at stress levels below the ultimate tensile strength (UTS). Damage modeling has been successful in predicting the number of cycles required to induce failure in a specimen due to stress. However, it does not …

Investigations Of The Photocatalytic Activity And Self-Cleaning Properties Of Polyhedral Oligomeric Silsesquioxane (Poss) Containing Titania Thiol-Ene Films, Lacrissia Unsonta Jefferson

Dissertations

In this document the film composition, self-cleaning aspect, photocatalytic efficiency, and methods employed to analyze a novel photocatalytic titania-containing thin film was evaluated. A primary objective of this research project was to assess the conditions required to achieve a stable titania dispersion for the photocatalytic coating and to determine the extent to which the presence of additives contributes to this process. Modified titania dispersions were prepared and characterized via dynamic light scattering (DLS), transmission electron microscopy (TEM), fourier transmission infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). Characterization details of the previous focus on the influence of polyhedral oligomeric silsesquioxane (POSS) …

Modifications Of Lysozyme By Substituted Benzoquinones, Hendrik J. Greve

Honors Theses

Amyloidosis, which involves the precipitation of mis-folded protein aggregates, is a prominent process that occurs in many neurodegenerative conditions such as Alzheimer's disease and Parkinson's disease; the protein aggregates being amyloid-β for Alzheimer’s disease and α-synuclein for Parkinson’s disease. This study has focused on lysozyme modifications induced by metabolites of the commonly found pollutants known as polycyclic aromatic hydrocarbons (PAHs). PAHs are found in substances ranging from grilled meats to cigarette smoke to cosmetics, and they can be metabolized into a family of biological toxins known as benzoquinones. The molecules of interest for this study were 1,4-benzoquinone (pBQ), 2-chloro-1,4-benzoquinone (CBQ), …

Determination Of Antibiotic Release From Electrospun Nanofibers, John P. O'Brien Iii

Honors Theses

Decreasing the risk of infection following surgery for traumatic bone breaks is a major focus of the medical and scientific community. Drug delivery devices are emerging as powerful solutions for combating infection following these procedures. Current devices, however, suffer several drawbacks including poor antibiotic release rate and control the devices themselves not being biodegradable. This thesis studies the \textit{in vitro} release rate for antibiotics tobramycin and vancomycin from a biodegradable medical implant. Antibiotics, collagen, and bone growth factors are incorporated into Poly(lactide-co-glycolide)-based electrospun nanofibers by local company eSpin for development. The drug-loaded nanofibers are immersed in phosphate buffered saline (PBS) …

Synthesis Of Novel Dienes And Cyclic Compounds Via Olefin Metathesis Reactions Catalyzed By The Second Generation Grubbs Catalyst, Patrick Joseph Carey

Honors Theses

Transition metal-catalyzed olefin metathesis reactions play a significant role in chemical synthesis. These reactions are currently applied across several disciplines, and their full potential has not yet been reached. This project details the synthesis of spiro[3-cyclopentene-1,9’-[9H]fluorene], 1-(1-amino-2-methylpropyl)-3-cyclopentenol, and the eugenol dimer via olefin metathesis reactions catalyzed by the second generation Grubbs catalyst. The unique structural properties of each compound help demonstrate the widespread abilities of these reactions. Also reported are the novel three-dimensional crystal structures of both spiro[3-cyclopentene-1,9’-[9H]fluorene] and the eugenol dimer. These structures were determined via X-ray diffraction crystallography methods using a Bruker SMART X2S Single Crystal Diffractometer. Both …