Chemistry Commons^™

Computational Studies Of Alkane C-H Functionalization By Main-Group Metals, Samantha Jane Gustafson

Theses and Dissertations

The most efficient homogeneous catalysts for hydroxylation of light alkanes utilize transition metals in superacid solvent and operate by tandem electrophilic C-H activation/metal-alkyl (M-R) functionalization. An emerging alternative strategy to transition metals is the use of high-oxidation state main-group metals (e.g. TlIII, PbIV, IIII) that hydroxylate light alkanes. This dissertation reports density-functional theory calculations that reveal the mechanisms, reactivity, and selectivity of TlIII promoted alkane C-H functionalization in trifluoroacetic acid and TlIII-dialkyl functionalization in water. Calculations reveal that TlIII oxidizes alkanes via a closed-shell C-H activation and M-R functionalization mechanism that is similar to transition-metal C-H functionalization mechanisms. Comparison of …

Gas Phase Structure Characterization Using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, Anupriya Anupriya

Theses and Dissertations

This dissertation investigates Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS) based techniques to study the impact of molecular structure on conformation and binding energetics. A novel method to determine collison cross sectional areas using FTICR (CRAFTI), initially developed by the Dearden lab, was applied to study the conformations of molecular systems with unique structural attributes in an attempt to explore the molecular range of CRAFTI. The systems chosen for CRAFTI studies include crown-ether alkylammonium complexes and biogenic amino acids. The results were found to be consistent with expected behavior, and strongly correlated with experimental measurements made using ion mobility …

Quantum Dot Metrics For Preparative Chemistry And Fluorescence Applications, Yi Shen

Theses and Dissertations

Colloidal semiconductor quantum dots (QDs) are considered to be a promising candidate for bio-imaging and solar cells because of their extraordinary photo-physical properties. The ultimate goal of this dissertation is to design a reliable matrix and a reproducible method to prepare QDs-based biocompatible probe for fluorescence applications. Synthesis of quantum dots requires a large amount of ligands to improve the stability at high temperature. However, for further application and surface modification of QDs, excess ligands must be removed. In this dissertation, I will first describe using gel permeation chromatography (GPC) as a media to purify different types of QDs. A …

Iron Uptake And Accumulation Is A Target Of Nickel Toxicity During The Lag Phase In Escherichia Coli, Geoffrey Tuttle Ford

Theses and Dissertations

Various transition metals are essential to all forms of life, and are only required in trace amounts. But this dependence comes as a double-edged sword. All organisms must maintain a careful intracellular quota that does not traverse outside an acceptable range. One transition metal in particular is nickel. The importance of this transition metal has been debated widely and its function varies greatly between organisms, including bacteria. However, the adverse effects caused by over exposure to this metal have been the center of much experimentation in recent years. Still, the mechanisms of nickel toxicity and the subsequent effects on cellular …

The Development Of A High Resolution Deep-Uv Spatial Heterodyne Raman Spectrometer, Nirmal Lamsal

Theses and Dissertations

Raman spectroscopy is a light scattering technique that has a huge potential for standoff measurements in applications such as planetary exploration because a Raman spectrum provides a unique molecular fingerprint that can be used for unambiguous identification of target molecules. For this reason, NASA has selected a Raman spectrometer as one of the major instruments for its new Mars lander mission, Mars 2020, in the search for biomarkers that would be the indicators of past or present life. Raman scattering is strongest at UV wavelengths because of the inherent increase in the Raman cross section at shorter wavelengths and because …

Ligand-Induced Magnetic Changes In Metal Thin Films, Fiona Senta Oberbeck-Oxsher

Theses and Dissertations

The investigation of magnetic properties of thin films whose surfaces were modified by organic molecules shows that the addition of any functional group to the surface measurably changes the magnetic properties. The effect often scales with ligand strength and is not limited to surfaces with ferromagnetic properties. Improving upon the technique developed by Knaus et al. [1], a stable and sensitive device was developed to measure this magnetic effect using the planar Hall effect (PHE) in order to shed light onto controversial questions of purported paramagnetism of thiolated gold. There is a measureable non-diamagnetic response of thin gold layers when …

Structural And Functional Studies Of Nicotinamide Adenine Dinucleotide And Streptolysin S Biosynthesis Proteins From Streptococcus Pyogenes, William T. Booth

Theses and Dissertations

Invasive infections caused by Streptococcus pyogenes, also known as Group A Strep (GAS), results in approximately 600,000 deaths annually. With evidence of antibiotic-resistant strains of this bacterium on the rise, there is a need for the identification of new drug targets to control these infections. In our approach we target the quinolinate-salvage pathway (QSP) and the streptolysin S (SLS) biosynthesis pathway. The QSP provides a secondary pathway for NAD+ biosynthesis within this organism; the SLS pathway leads to the formation of a quorum sensing molecule (SLS). We hypothesize that inhibition of the pathways will lead to GAS cell death or …

Synthesis And Biological Activity Of Novel Quorum Sensing Compounds, Joseph Nicholas Capilato

Theses and Dissertations

Bacteria communicate with chemical signals in a process known as quorum sensing. This population density-dependent process involves the bacterial production, release and detection of structurally specific small molecules and enables the bacterial pathogen to regulate its virulence on a population-wide level. Using a variety of chemical and biological techniques, I have studied various quorum sensing systems in several bacteria, including Vibrio cholera and Pseudomonas aeruginosa. A key principle of this research involves the design, synthesis and testing of novel compounds for their biological activity. These molecules are typically based off of an initial lead target, which is often identified …

Criteria For Selecting Pegylation Sites On Proteins For Higher Thermodynamic Stability, Paul B. Lawrence

Theses and Dissertations

PEGylation of protein side-chains has been used for more than 30 years to enhance the pharmacokinetic properties of protein drugs, and has been enabled by the recent development of many chemoselective reactions for protein side-chain modification. However, there are no structure- or sequence-based guidelines for selecting sites that provide optimal PEG-based pharmacokinetic enhancement with minimal loss to biological activity. Chapter 1 is a brief introduction to protein PEGylation. In chapter 2 we use the WW domain of the human protein Pin 1 (WW) as a model system to probe the impact of PEG on protein conformational stability. Using a combination …

Analyses Of Mrna Cleavage By Rele And The Role Of Trna Methyltransferase Trmd Using Bacterial Ribosome Profiling, Jae Yeon Hwang

Theses and Dissertations

Protein synthesis is a fundamental and ultimate process in living cells. Cells possess sophisticated machineries and continuously carry out complex processes. Monitoring protein synthesis in living cells not only inform us about the mechanism of translation but also deepen our insights about all aspects of life. Understanding the structure and mechanism of the ribosome and its associated factors helped us enlarge our knowledge on protein synthesis. Recently, with the dramatic advances of high-throughput sequencing and bioinformatics, a new technique called ribosome profiling emerged. By retrieving mRNA fragments protected by translating ribosomes, ribosome profiling reveals global ribosome occupancy along mRNAs in …

Glutamic Acid Resorcinarene-Based Molecules And Their Application In Developing New Stationary Phases In Ion Chromatography, Tayyebeh Panahi

Theses and Dissertations

Resorcinarenes can be functionalized at their upper and lower rims. In this work, the upper rim of a resorcinarene was functionalized with glutamic acids and the lower rim was functionalized with either methyl or undecyl alkyl groups. The cavitands were characterized by nuclear magnetic resonance (NMR), mass spectrometry (MS), UV-vis spectroscopy, dynamic light scattering (DLS) and electron microscopy. The binding of resorcinarene with amine guests was studied in DMSO by UV-vis titration. The obtained binding constants (K values) were in the range of 12,000-136000 M-1. The resorcinarenes were shown to form aggregates in a variety of solvents. The aggregates were …

Inhibitory Effects Of Unique Sulfonamides On Leishmania Tarentolae And Potential Pathway Of Inhibition, Jade M. Katinas

Theses and Dissertations

Leishmaniasis is an endemic disease caused by the protozoan parasite Leishmania. Current treatments for the parasite are limited by cost, availability, and drug resistance as the worldwide occurrence of leishmaniasis continues to be more prevalent. Sulfonamides are a class of compounds with medicinal properties that have been used to treat bacterial and parasitic diseases via various pathways. In this study, newly synthesized, unique structural analogs of sulfonamide compounds were assessed for their impact on Leishmania cell viability and potential pathways for inhibition were evaluated. Leishmania tarentolae (ATCC Strain 30143) axenic promastigote cells were grown in BHI medium and treated with …

Role For Reactive Oxygen Species In Methamphetamine Modulation Of Dopamine Release In The Striatum, David Matthew Hedges

Theses and Dissertations

Methamphetamine (METH) is a highly addictive substance that is highly prevalent in today’s society, with over 1 in 20 adults over 26 having taken it at least once. While it is known that METH, a common psychostimulant, acts on both the mesolimbic dopamine (DA) and nigrostriatal DA systems by affecting proteins involved in DA reuptake and vesicular packaging, the specific mechanism of what is known as METH neurotoxicity remains obscure, but has been shown to involve oxidative stress. Studies have shown that reactive oxygen species act on the same proteins that METH affects. Oxidative species have also been known to …

Development Of Arginyl-Trna Synthetase From Pseudomonas Aeruginosa As A Platform To Screen For Inhibitors Of Protein Synthesis, Daniel Cantu

Theses and Dissertations

Pseudomonas aeruginosa is a Gram- negative bacteria that is the leading cause of mortality in immunocompromised patients. Arginyl-tRNA synthetase (ArgRS) is an enzyme that catalyzes the covalent attachment of arginine to the cognate tRNAArg during protein synthesis. Scintillation proximity assays (SPA) were adapted to the aminoacylation assay and used to screen, one natural compound library (800) and one synthetic compound library (890) to identify inhibitors of the activity of ArgRS. Five compounds were identified which inhibited greater than 50% of enzymatic activity, two of these compounds (BT04F10 and BT11F03) exhibited promising MICs against Gram+ bacteria and moderate activity against Gram- …

Placental ‘€˜Omics’€™ Study To Understand The Pathogenesis Of Preeclampsia, Komal Kedia

Theses and Dissertations

Preeclampsia (PE) is a potentially fatal complication of pregnancy characterized by an increase in blood pressure (>140/90 mmHg) and proteinuria (>300 mg/24 hrs), often accompanied by edema. Symptoms of PE start after 20 weeks of gestation. If PE remains untreated, it can lead to eclampsia, grand-mal seizures responsible for most fatalities. PE is believed to affect 2-10% of pregnancies worldwide, and claims the lives of over 75,000 mothers and 500,000 newborns yearly. No therapeutic agents have been developed to prevent or cure PE. Part of the reason for this is the absence of a complete understanding of the …

Identification Of Synthetic Chemical Compound Inhibitors Of Pseudomonas Aeruginosa Protein Synthesis And The Development Of Lead Series, Stephanie O. Palmer

Theses and Dissertations

Pseudomonas aeruginosa is a ubiquitous Gram-negative bacteria and a primary cause of nosocomial infections. An aminoacylation/translation (A/T) assay was developed using P. aeruginosa components to perform poly(U) mRNA directed protein synthesis. Using scintillation proximity assay (SPA) technology a high-throughput screening (HTS) platform was developed. A synthetic chemical compound library (>900) was screened, 36 hit compounds were identified and molecular targets were determined. Compounds were analyzed for enzymatic inhibition (IC50) and inhibition of bacterial cultures (MIC). Time-kill studies determined bacterial growth to be bacteriostatic or bactericidal in the presence of inhibitor. Mechanism of action, effects on eukaryotic cytosolic and mitochondrial …

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 …

Removal Of Perfluorooctanoic Acid From Water Using Primitive, Conventional And Novel Carbonaceous Sorbent Materials, Christopher K. Brown

Theses and Dissertations

Polyfluoroalkyl Substances (PFAS), like perfluorooctanoic acid, have been used for the last 50 years in a wide variety of industrial processes and consumer-based products, including polymer additives, lubricants, fire retardants and suppressants, pesticides, and surfactants (Buck et al. 2015). The Department of Defense (DoD) has used PFAS-based Aqueous Film Forming Foam (AFFF) at fire training facilities and aircraft hangars. AFFF has contaminated approximately 600 sites classified as fire training facilities with PFAS (Huang, 2013).

This study focused on testing the most likely carbonaceous adsorbent compounds to remediate PFAS-contaminated sites on Air Force installations. Batch tests were performed to determine the …

Development And Application Of New Solid-State Models For Low-Energy Vibrations, Lattice Defects, Entropies Of Mixing, And Magnetic Properties, Jacob M. Schliesser

Theses and Dissertations

Low-temperature heat capacity data contain information on the physical properties of materials, and new models continue to be developed to aid in the analysis and interpretation of heat capacity data into physically meaningful properties. This work presents the development of two such models and their application to real material systems. Equations describing low-energy vibrational modes with a gap in the density of states (DOS) have been derived and tested on several material systems with known gaps in the DOS, and the origins of such gaps in the DOS are presented. Lattice vacancies have been shown to produce a two-level system …

Discovery Of Low-Molecular Weight Novel Serum Biomarkers For Diagnosing Preeclampsia And Alzheimer's Disease, Swati Anand

Theses and Dissertations

Preeclampsia (PE), a life threatening pregnancy-related disorder, is characterized mainly by new onset of hypertension and proteinuria after 20 weeks of gestation. Currently, PE cannot be predicted prior to onset of symptoms and there is no cure for the disease. There is a clear value in having biomarkers able, early in a pregnancy, to identify women at risk for PE so that proper treatment therapies could be developed. Although a number of serum candidate markers have been proposed to be altered in PE patients, their use is limited due to poor sensitivity and specificity. Therefore, there is ongoing need for …

14-3-3Ζ Regulation Of Metastasis Through Mediation Of Liprin-Α And Liprin-Β, Rachel Hynes

Theses and Dissertations

Cancer is a set of varied and diverse diseases that share common characteristics, such as active proliferation, increased replicative potential, and tissue invasion or metastasis. One protein, 14-3-3ζ, is shown to be upregulated in a number of different cancers and also correlates with poor patient prognosis, recurrence, and mortality. This protein comes from a family of adapter proteins known for their scaffolding ability, pro- and anti-oncogenic capabilities, and affinity for phosphorylated substrates. It has been shown previously to participate in cancer progression, subversion of apoptosis, and to increase chemoresistance. Herein we will discuss the ability of 14-3-3ζ to promote distant-site …

Novel Sputtered Stationary Phases For Solid Phase Microextraction, And Other Coatings And Materials For Surface Applications, Anubhav Diwan

Theses and Dissertations

The primary focus of my work has been to prepare new solid adsorbents for solid phase microextraction (SPME) via sputtering of silicon. The orientation of the silica substrates/fibers and the sputtering pressure induced the formation of porous and columnar structures. Sputtering was performed for different times to yield fibers with different thicknesses. Piranha treatment of the surface increased the concentration of silanol groups, which underwent condensation with vapor deposited octadecyldimethylmonomethoxy silane to incorporate octadecyl chains onto the fiber surfaces. Silanized, sputtered fibers were preconditioned for 3 h at 320 °C to remove the unreacted chains. Comparison of the extraction efficiencies …

Synthesis And Applications Of Graphene Oxide And Its Derivatives And Composites, Daoyuan Wang

Theses and Dissertations

Graphene oxide (GO), a monolayer of graphite oxide and an oxidized form of graphene, has attracted tremendous attention in the last decade due to its unique physical and chemical properties. This dissertation is devoted to three research areas: 1) The hydration behaviors of GO membranes, 2) The thermal reduction behaviors of GO membranes and the GO and reduced GO (RGO)-based filtration membranes for water purification, and 3) Photo- and electro-catalytic water splitting properties of GO-based derivatives and nanocomposites with other catalytic nanomaterials for hydrogen and oxygen production. 1) The hygroscopic nature of GO and the hydration behavior of trapped water …

Sol-Gel Synthesis Of Intermediate Composition, Nanocrystalline Olivine, Corbin Cannon

Theses and Dissertations

Olivine is one of the most important rock forming minerals in our solar system. It forms in a solid-solution series between a magnesium-rich end member, forsterite (Mg2SiO4), and an iron-rich end member, fayalite (Fe2SiO4). For this reason, it is commonly used for experiments regarding the formation and evolution of planetary objects. Scarcity of iron-rich phases and the desirability of pure materials for research force the use of synthetic minerals for these experiments. Previous forsterite and fayalite synthesis methods were reexamined and combined to develop a new synthesis method that can produce a specific composition of olivine within the solid solution …

Solid State Synthesis And Characterization Of The Rare Earth-Free Anti-Perovskites Sr2.5-Xba0.5 Al1-Xp Xo4 F ( 0 ≤ X ≤ 0.15 ), Sr3al1-Xy Xo 4 F ( 0 ≤ X ≤ 1 ), And Sr2.5-X/2ba0.5 Al1-Xhfxo4 F ( 0 ≤ X ≤ 0.1 ) As Potential Phosphor Materials, Sean Thomas Keil

Theses and Dissertations

Typical lighting systems such as incandescent and fluorescent bulbs are common in homes but are rather inefficient compared to the newer light emitting diodes (LEDs). LED-based lamps can be constructed to generate white light by combining a red, green, and blue LED, or by using an LED light source (typically with a low wavelength) with a complimentary phosphor coating to produce white light. The latter, known as phosphor-conversion (PC) LEDs, is the primary focus of this research, looking specifically at rare earth-free options for these phosphor coatings.

Anti-perovskites are a potential lattice type for this type of conversion, in particular …

Determination Of Fine Particulate Matter Composition And Development Of The Organic Aerosol Monitor, Paul Michael Cropper

Theses and Dissertations

Tropospheric fine particulate matter (PM) poses serious health risks and has a significant impact on global climate change. The measurement of various aspects of PM is challenging due to its complex chemical nature. This dissertation addresses various aspects of PM, including composition, measurement, and visibility. The U.S. Environmental Protection Agency (EPA) proposed a new secondary standard based on visibility in urban areas using 24-h averaged measurements of either light scatter or PM concentration. However shorter averaging times may better represent human perception of visibility. Data from two studies conducted in Lindon, UT, 2012, and Rubidoux, CA, 2003, were used to …

The Dawn Of New Quantum Dots: Synthesis And Characterization Of Ge1-Xsnx Nanocrystals For Tunable Bandgaps., Richard J. Esteves

Theses and Dissertations

Ge_1-xSn_x alloys are among a small class of benign semiconductors with composition tunable bandgaps in the near-infrared spectrum. As the amount of Sn is increased the band energy decreases and a transition from indirect to direct band structure occurs. Hence, they are prime candidates for fabrication of Si-compatible electronic and photonic devices, field effect transistors, and novel charge storage device applications. Success has been achieved with the growth of Ge_1-xSn_x thin film alloys with Sn compositions up to 34%. However, the synthesis of nanocrystalline alloys has proven difficult due to larger discrepancies (~14%) in …

Drying Methods For The Fabrication Of Polymer Foam Material, Dalton Echard

Theses and Dissertations

This is a report on the study of the drying of nanoporous polymer foam material fabricated by photolithogtaphic methods. Three drying methods were employed, which were air drying, supercritical drying and freeze drying. After fabrication and drying, physical properties of the polymer foams were measured. These measurements included density of the material, Young’s modulus, surface area, and the shape of the skeletal particles. The measurements determined the effect of the polymer concentration and the effect of drying methods. It was determined that polymer concentration had a much larger effect on the properties of the materials than the drying method.

Electronic Structure And Stability Of Ligated Superatoms And Bimetallic Clusters, William H. Blades

Theses and Dissertations

Quantum confinement in small metal clusters leads to a bunching of states into electronic shells reminiscent of shells in atoms. The addition of ligands can tune the valence electron count and electron distribution in metal clusters. A combined experimental and theoretical study of the reactivity of methanol with Al_nI_m⁻ clusters reveals that ligands can enhance the stability of clusters. In some cases the electronegative ligand may perturb the charge density of the metallic core generating active sites that can lead to the etching of the cluster. Also, an investigation is conducted to understand how the bonding …