Physical Sciences and Mathematics Commons^™

Syntheses And Reactions Of Early Transition Metal Amidinate Compounds, Adam Christopher Lamb

Doctoral Dissertations

Homoleptic Groups 4 and 5 metal amide compounds have been used as precursors in CVD/ALD processes to make microelectronic metal oxide thin films. These compounds are often very air sensitive. Ancillary ligands such as amidinates have been used to reduce their air sensitivity and to make their handling easier. Reactions of amidinates with dioxygen and water have thus been used to make metal oxide thin films. Studies of these reactions are important in order to make better precursors and purer thin films. This dissertation focuses on the following areas: (a) Syntheses of zirconium and Group 5 amidinate amides; (b) Studies …

Design And Synthesis Of Novel Sultams As Non-Nucleoside Inhibitors Of Hiv Reverse Transcriptase, Brian Chadwick Lecroix

Doctoral Dissertations

The compound 2-methyl-3-phenyl-2,3-dihydro-1,2-benzisothiazole 1,1-dioxide (NSC 108406) was identified as an HIV-1 reverse transcriptase inhibitor by the National Cancer Institute. Using this lead, the Baker group has developed a series of analogues with various groups at the 3-position that show a spectrum of biological activities. In the end, the substituents used could not compare to the biological activity of the inhibitor efavirenz (Sustiva^® [trademark]), and so it was decided to synthesize sultams with alkylethynyl substituents at the 3-position of the sultams in an attempt to mimic the activity of efavirenz.

Previous research analyzed the proposed novel sultams in the modeling …

Synthesis And Characterization Of Fullerene-Based Hydrogen Storage Materials, Patrick Alan Ward

Doctoral Dissertations

Storing hydrogen safely and efficiently is an area of great interest for the utilization of hydrogen as an energy carrier in transportation applications. The feasibility of using fullerenes in hydrogen storage materials was investigated. Alkali decorated fullerenes Li_xC₆₀ [LixC60] and Na_xC₆₀ [NaxC60] were found to enhance the hydrogen chemisorption and physisorption properties of fullerenes. Although the overall hydrogen physisorption uptake in these materials is low due to the crystalline nature of the material, the isosteric heats of adsorption of fullerenes were increased by lithium doping. C₆₀ [C60] is also capable of acting as …

Magneto-Optical Properties Of Complex Oxides, Peng Chen

Doctoral Dissertations

Complex oxides give rise to rich physics and exotic cross-coupled electronic and magnetic properties. This is because of the competing interaction between charge, structure, and magnetism in the materials. In this dissertation I present a spectroscopic investigation of several model complex oxides under external stimuli of magnetic field and temperature. The compounds of interest include BiFeO₃ [bismuth ferrite] nanoparticles and tetragonal film, Bi_1-xNd_xFeO₃ [neodymium doped bismuth ferrite], α-Fe₂O₃ [hematite], Ni₃V₂O₈ [nickel vanadate], and RIn_1-xMn_xO₃ [manganese doped rare earth indium oxide]. …

Characterization Techniques And Electrolyte Separator Performance Investigation For All Vanadium Redox Flow Battery, Zhijiang Tang

Doctoral Dissertations

The all-vanadium redox flow battery (VRFB) is an excellent prospect for large scale energy storage in an electricity grid level application. High battery performance has lately been achieved by using a novel cell configuration with advanced materials. However, more work is still required to better understand the reaction kinetics and transport behaviors in the battery to guide battery system optimization and new battery material development. The first part of my work is the characterization of the battery systems with flow-through or flow-by cell configurations. The configuration difference between two cell structures exhibit significantly different polarization behavior. The battery output can …

Synthesis Of A Bifunctional Heterogeneous Catalyst For The Conversion Of Lignocellulosic Biomass Into Precursors For Alternative Fuels And Fine Chemicals, Matthew David Dembo

Masters Theses

The overall goal of the research described here is to develop synthetic routes to bifunctional reagents that can be tethered into silicate matrices derived from the tin functionalized cube, Si₈O₂₀(SnMe₃)₈. The critical functional group required for reaction with cubic silicate building block is a chlorosilane, and we additionally wish to incorporate both acid and ionic liquid groups. Once in hand, a crosslinking metathesis reaction will incorporate these reagents into porous silicate matrices derived from the Si₈O₂₀ cube, creating platforms with both acid and ionic liquid groups tethered to their …

Time Dependent Density-Functional Theory - Linear Response, Bryan Edman Sundahl

Masters Theses

The formal derivation of the linear response of time-dependent density-functional theory as shown by E. K. U. Gross is presented. The transformation of formal theory to the working linear response equations in the form of Casida's eigenvalue equation is demonstrated, and the results are applied to small monatomic, diatomic and triatomic systems. The application of different operators to the perturbed density is discussed, with the most attention being given to the dynamic polarizabilities. The dynamic polarizabilities and excitation spectra for N₂ [nitrogen gas] are then analyzed. The first excitation energy is noted to be in line with Koopmans' theorem. …

Demonstration Of A Targeted Proteome Characterization Approach For Examining Specific Metabolic Pathways In Complex Bacterial Systems, Adam Justin Martin

Masters Theses

Multiple Reaction Monitoring (MRM) is a powerful tandem mass spectrometry (MS/MS) tool frequently implemented in proteomic studies to provide targeted analysis of proteins and peptides. The selectivity that MRM delivers is so strong that it provides the quadrupole mass spectrometers (QQQ), on which it is commonly employed, with pertinence to proteomic studies that they would otherwise lack for their relatively low resolution. Additionally, this increased level of selectivity is sufficient enough to supplant complicated fractionation techniques, additional dimensions of chromatography, and 24 hour long MS/MS experiments in simplistic biological samples. But there is a deficiency of evidence to determine the …

The Development Of Lithium Tetraborate Compounds For Thermal Neutron Detection, John David Auxier Ii

Doctoral Dissertations

Due to the shortage of ³He [helium-3], the goal of this project was to develop replacement materials for slow neutron detection in mixed radiation fields. The U.S. Department of Homeland Security (DHS) indicated that replacement materials should have an absolute neutron efficiency of 2.5 cps/ng of ²⁵²Cf (Californium-252) and a neutron/gamma discrimination intrinsic efficiency of 1 x 10^-6 [one gamma-ray response in a million counts]. In this work, the use of amorphous lithium tetraborate (Li₂B₄O₇:Ce) is analyzed as a thermal neutron detector. Also discussed is the synthesis of the lithium tetraborate, …

Developing 16- And 18-Atom Ringed Macrocyclic Tetracarbene Complexes, Heather Marie Bass

Doctoral Dissertations

Stabilizing metal-ligand multiple bonds is important for the understanding of biological intermediates, as well as, for their use in group transfer reactions. Two considerations to make when developing a ligand system to support metal-ligand multiple bonds are the strength of the ligand and the symmetry of the ligand. Herein, our group has proposed a class of four-coordinate, strong σ-donor ligands by synthesizing macrocyclic tetraimidazoliums that form tetracarbenes upon deprotonation. By examining group theory, these systems should allow for the formation of complexes with metal-ligand multiple bonds in a bent square pyramidal geometry that exhibit high oxidation states and novel spin …

Syntheses, Characterization And Reactions Of Early Transition Metal Guanidinate And Imide Compounds, Bhavna Sharma

Doctoral Dissertations

Early transition metal compounds and their reactions have been widely used in catalysis and preparation of advanced materials such as metal oxides in microelectronic devices. Studies of the compounds and their reactions provide a fundamental understanding of chemistry of the compounds and are critical to their applications. This dissertation focuses on the following areas: (a) Reactions of Group 4 amide guanidinates with dioxygen or water; (b) Formation of a tantalum imide complex through an unusual α [alpha]-SiMe₃ [trimethylsilyl] abstraction. Reactions of the amide guanidinates with either dioxygen or water yield products that are identified to be dimers and polymers …

Copper Mediated, Transmetallation Coupling Reactions Using High Intensity Ultrasound, Bryan J. Musolino

Doctoral Dissertations

This dissertation summarizes research efforts focused on the use of boron and copper acetate to form new carbon-carbon and carbon-heteroatom bonds. Two new methods were developed using high intensity ultrasound as the reaction energy source. The first focused on the homocoupling of various aryl compounds using a commercially available polymer support. The use of this polymer support allows the reaction to proceed in an aqueous solvent system with only minimal preparation. The product yields were better than values reported in the literature using traditional reaction conditions and reaction times were decreased from 24-72 hours to 6 hours. The second method …

Neutron Scintillation Detectors Based On Polymers Containing Lithium-6 For Radiation Portal Monitor Applications, Andrew Neil Mabe

Doctoral Dissertations

The work presented herein describes an investigation of four main types of thin film polymer scintillators containing ⁶Li [lithium-6] for neutron detection: polystyrene containing ⁶LiF [lithium-6 fluoride] and a preblended fluor mixture comprising 2,5-diphenyloxazole and 1,4-bis(5-phenyloxazol-2-yl)benzene; poly(styrene-co-lithium maleate) containing salicylic acid; poly[styrene-co-lithium maleate-co-2-phenyl-5-(4-vinylphenyl)oxazole]; and poly(styrene-co-lithium 4-vinylbenzoate). A variety of chemical and physical characterizations as well as optical and scintillation characterizations were performed to guide the development of optimized compositions of each type of polymer film. The scintillation performances of optimized compositions of each type of polymer film were calibrated using …

Phosphatidylinositol 3,4,5–Trisphosphate Probe Synthesis And Microarray Protein Binding Studies To Investigate Multivalency And Detect Proteins Upregulated In Cancer, Benjamin Michael Smith

Masters Theses

Protein–lipid binding interactions control many processes at the cellular level. Many of these biological events between proteins and lipids are often associated with signaling pathway diseases such as cancer and diabetes. Therefore, increasing our knowledge of protein–lipid binding interactions will provide a better understanding of the signaling pathways of living systems. Pursuing this further, the phosphatidylinositol polyphosphates (PIPs) are an important family of signaling lipids that control key biological processes. Thus, the work described in this thesis was aimed at developing methods to validate these types of lipid–protein binding interactions. The goals of these projects were to synthesize the PIP …

Hindered Rotation Of Dihydrogen On Synthesized Metal Oxides, George Houston Rouvelas

Masters Theses

A MATLAB program was written to calculate the hindered rotational energies of the hydrogen and deuterium molecules interacting with an anisotropic potential, which may be thought of as a potential energy surface of a metal oxide substrate. It was found that an increase in the hindering potential of the rotation about the azimuthal angle lifted the degeneracy of the j = 1,mj [magnetic quantum number] = plus or minus 1 states. A better understanding of how the rotational states of these systems change as a function of the hindering potential can help to explain features in rotational inelastic neutron scattering …

An Investigation Into The Sustainability Of Advanced Materials And Systems As Energy Sources In Commuter Transportation, Austin Alan Albert

Chemistry Publications and Other Works

Modern society depends on cheap and plentiful sources of energy. For most of the 20th century, fossil fuel in the form of coal, natural gas, and petroleum have been this energy source. The majority of petroleum in the U.S. goes in to fueling the light duty transportation fleet. However, we know that coal, natural gas, and crude oil have an expiration date, and we have recently learned that their use has caused and is still causing severe damage to the earth’s atmosphere. With these reasons in mind, new sources of inexpensive and abundant energy must be found, which are renewable …

Moving Toward Sustainable Production Of Charcoal In Sub-Saharan Africa: A Teaching Case Study, Justin Taylor Roop

Chemistry Publications and Other Works

In the developing world, wood fuels play a major role in supplying energy needs. In sub-Saharan Africa, much of this wood fuel is in the form of charcoal used for cooking. As much as 90% of the cooking performed in these countries use charcoal as the energy source. With this massive quantity being produced and sold, the charcoal sector presents a major area in which sustainable development can be implemented with a large positive impact. At present, deforestation, pollution, and inequitable distribution of profits threaten the long-term viability of this industry. This teaching case study presents the background of the …

New Applications Of Boron Dihalides And Organotrifluoroborates In Organic Synthesis, Kelly Elizabeth Hall

Doctoral Dissertations

This dissertation summarizes research focused on the use of boron dihalides and organotrifluoroborates in organic synthesis. The boron dihalide mediated aryl propargyl ether cleavage reactions to generate the corresponding aryl alcohols were investigated to explain the mechanistic pathway of using boron trihalides and boron dihalides in propargyl ether cleavage reactions. The results of this study strongly support that the mechanistic pathway for these reactions follows the pathway shown in this dissertation. In addition, the use of polymer-supported organotrifluoroborates for radiolabeling reactions was also investigated. The results of these studies support the use of polymer supported organotrifluoroborates in radiolabeling reactions as …

1,2,4-Triazine-Accelerated Azide-Alkyne Cycloaddition And Synthesis Of Metalloenzyme Inhibitors, Belinda Shea Lady

Doctoral Dissertations

The work of this dissertation describes the design and synthesis of 1,2,4-triazine ligands and other N-containing heterocycles and their use in the copper-catalyzed azide-alkyne cycloaddition (CuAAC). A variety of ligands were synthesized to probe the steric and electronic demands required for use in the CuAAC reaction. Substituents on the 1,2,4-triazine were systematically altered and the core 1,2,4-triazine modified to determine the most active ligand. Additional experiments explored the variability in the reaction conditions, such as solvent choice, use of reducing agents, and optimal stoichiometry. Under optimum conditions 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine and copper (II) tetrafluoroborate in the presence of triethylamine was found to …

Fluorescence Spectroscopy With Correlated Atomic Force Microscopy Of Gold Nanoparticles And Meso-Scale Ribbons, Meredith Marie Therrien

Doctoral Dissertations

Studies on the optical properties of gold nanoparticles are of great interest due to the size and shape control and easy adaptability through functionalization to most any application, everything from nanomedicine to nanosensing. Gold nanoparticle optical properties change with size, morphology, and environment. Gold nanospheres were explored to determine the effect of environmental change, from many particles in solution to a single particle immobilized and in air, on fluorescence peak position. A statistical distribution of single gold nanorod fluorescence spectra demonstrate the spectral changes associated with slight variations in size. In solution, gold nanorods self-absorb and only exhibit bulk gold …

Tuning Sol-Gel Phase Diagrams Of Doubly Thermosensitive Hydrophilic Diblock Copolymers In Water, Naixiong Jin

Doctoral Dissertations

This dissertation presents the synthesis of stimuli-responsive hydrophilic diblock copolymers and the study of their behavior in water under various conditions. The polymers were made by “living”/controlled radical polymerization. Chapter 1 presents a background of this dissertation. Chapters 2-4 describe a family of doubly thermosensitive diblock copolymers with a small amount of carboxylic acid groups incorporated into either one or both blocks. The lower critical solution temperature (LCST) of the weak acid-containing block increases with increasing pH due to the ionization of carboxylic acid. Chapter 5 presents the preparation of pH-sensitive diblock copolymer micelle-embedded agarose hydrogels.

Chapter 2 describes the …

Resonance Hyper-Raman Characterization Of Nonlinear Chromophores, Christopher Bennett Milojevich

Doctoral Dissertations

Hyper-Raman spectroscopy is a nonlinear optical probe which can be used to explore the multi-photon properties of molecules. Three studies are presented in this dissertation. The first study is a combined experimental investigation of the surfaceenhanced hyper-Raman scattering with a theoretical study of the electronic states of the Rhodamine 6G molecule. This study demonstrates that hyper-Raman spectroscopy can be used to probe electronic states which are one-photon inaccessible. The second study involves a comparison of experimentally measured resonance hyper-Raman spectra to first-principles calculations of the resonance hyper-Raman scattering. This study shows the utility of coupling hyper-Raman spectroscopy and hyper-Raman calculations …

Alkane Adsorption On Mgo(100): Volumetric Isotherm, Inelastic Neutron Scattering, And Computational Studies, Andrew Spencer Hicks

Doctoral Dissertations

Volumetric adsorption isotherms and computational molecular dynamics (MD) simulations were performed for nonane and decane adfilms on MgO(100) nanocubes. From the isotherms, variety of thermodynamic quantities are calculated. These values, along with visual inspection of the isotherms, indicate a layer by layer trend from 2D to 3D behavior. This is attributed to the increasing importance of vertical adsorbate-adsorbate interactions as distance from the surface increases. Additionally, a 2D phase transition is observed for the first adsorbed layer as indicated by the evolution of the widths of the isotherm first derivative peaks. These experimental results are complemented by the MD calculations, …

Quorum Sensing And Metabolism In Marine Environments, Amanda May

Doctoral Dissertations

Quorum sensing (QS) is a phenomenon that allows bacteria to communicate with each other. Small molecules known as autoinducers are synthesized and released by bacteria, and once enough members of the community are around to ensure survival, i.e. quorum, a phenotype, e.g. bioluminescence, is expressed. There are two types of QS molecules, intra- and inter-species.

S-4,5-Dihydroxy-2,3-pentanedione (DPD) is a byproduct of the activated methyl cycle which recycles methionine. This has led to the discussion as to whether DPD is a metabolic byproduct or is the interspecies signal as proposed previously. The detection and quantitation of DPD however, has not …

Synthesis And Characterization Of Stimuli Responsive Polymer Brushes, Chaitra Vasant Deodhar

Doctoral Dissertations

Polyelectrolytes (PE) are the least understood polymeric systems due to their complex behavior that arises because of the intimate connection between charge and conformation. To address this challenge, my research focuses on understanding the responsive behavior of weak polyelectrolyte brushes to different stimuli such as pH, type of ion and ionic strength. In this work, weak polyelectrolyte brushes made of poly(methacrylic acid) (PMAA) and random copolymer brushes incorporating hydroxyethyl methacrylate (HEMA) as co-monomer were studied. The polymer brushes were synthesized by both “grafting to” and “grafting from” approaches and were characterized mainly by ellipsometry and neutron reflectometry.

Several methods for …

Analysis Of Ecological Change In Marine Ecosystems Via Novel Imaging And Spectroscopic Techniques On Microalgae Cells, Morgan Breonne Mcconico-Lewis

Doctoral Dissertations

With the increase in anthropogenic pollutants such as: atmospheric CO₂ [carbon dioxide], fossil fuel combustion and fertilizer run off, the fate of the environment is of great importance. Through industrialization, the greenhouse gas, CO₂, is a major contributor to global warming; while nitrogen based fertilizer, causes the production of toxins due to harmful algal blooms. Both chemical impacts dissolve into marine ecosystems effecting the chemical composition of organisms such as microalgae. Microalgae remediate these changes by sequestering carbon and nitrogen; thus there is a need to understand how these impacts affect the ecosystem by detecting the change …

Relative And Absolute Quantitation Of Metabolites And Lipids Using Lc/Ms/Ms On The Tsq Quantum Discovery Max, Jesse Lee Middleton

Masters Theses

Two biological systems were studied using LC/ESI/MS/MS on a triple quadrupole operated in SRM (selected reaction monitoring) scan mode. The first bacterium system is aquatic and microscopic in size known as Roseobacter. The second mammalian system is terrestrial and large in size relative to humans known as Holstein cows.

Roseobacter is a clade of marine bacteria abundant in the ocean. Roseophages are viruses that infect Roseobacter and cause viral lysis. Sulfitobacter sp. 2047 was isolated and infected with Roseophages, and the fold change in the metabolic pool relative to a control was studied at discrete time points. The absolute concentration …

Adsorption Of Antimony By Birnessite And The Impact Of Antimony On The Electrostatic Surface Properties Of Variable-Charge Soil Minerals, Kalyn Alaine Vergeer

Masters Theses

Antimony (Sb) is a toxin that can be found in high concentrations in the soil due to anthropogenic sources. Antimony exists in soil as Sb(V) in the monovalent antimonate hydroxyanion. The adsorption mechanisms of Sb(V) are not well-characterized. The objective of this study was to further elucidate Sb(V) adsorption mechanisms by examining the impact of adsorption on surface charging characteristics of gibbsite, goethite, birnessite, and kaolinite. Also examined was Sb(V), SO₄ [sulfate], and PO₄ [phosphate] adsorption by birnessite. Electrophoretic mobility and potentiometric titrations were employed to examine the ζ-potential [zeta-potential] and net proton surface charge density as a …

Synthesis Of Isotopologues And Nanoparticles For Hyper Raman Spectroscopy, Burton K. Mandrell

Chancellor’s Honors Program Projects

No abstract provided.

Comparison Of Methodologies For Synthesis Of 3-(Cyclopropylethynyl)Benzisothiazole 1,1-Dioxide, Rachel Lee Naramore

Chancellor’s Honors Program Projects

No abstract provided.