Chemistry Commons^™

Development Of Novel Redox Sensors And Processes Towards Biological Applications, Jigna Patel

Electronic Theses and Dissertations

Research on the cure and early detection of diseases such as diabetes, Alzheimer's, and Parkinson's is becoming of great interest due to the increasing number of people affected by them every year. An accurate and quick detection of various damaging species is highly critical in treatments of such diseases not only for exploring possible cures but also for early detection. If these diseases are detected during the initial stages than the possibility of curing them is much higher. Motivated by this, many researchers today have developed numerous types of sensing devices that can detect various physiological and biological compounds. However, …

Novel Optical Properties Of Metal Nanostructures Based On Surface Plasmons, Haining Wang

Electronic Theses and Dissertations

Surface plasmons have been attracted extensive interests in recent decades due to the novel properties in nanometer sized dimensions. My work focused on the novel optical properties of metal nanostructures based on surface plasmons using theoretical simulation methods. In the first part, we investigated metal nanofilms and nanorods and demonstrated that extremely low scattering efficiency, high absorption efficiency and propagation with long distance could be obtained by different metal nanostructures. With a perforated silver film, we demonstrated that an extremely low scattering cross section with an efficiency of less than 1% can be achieved at tunable wavelengths with tunable widths. …

Biochemical Characterization Of The Nifb Enzyme And Nifb-Cofactor, Jirair Gevorkyan

Electronic Theses and Dissertations

The Mo-nitrogenase complex is composed of two components, Fe-protein and MoFe-protein. This complex is able to catalyze the reduction of N2 through the MgATP dependent transfer of electrons from the Fe-protein Fe4S4 cluster to the MoFe-protein P-cluster and, subsequently, to the iron-molybdenum cofactor (FeMoco). FeMo-co is a Fe7S9MoC-(R)-homocitrate cluster and has two biosynthetic precursors, NifB-co and L-cluster, of unknown structure and composition. The biosynthesis of FeMo-co is an enigmatic process that minimally requires NifB, NifEN, Fe-protein, MoO4 2- , (R)-homocitrate and S-adenolsylmethionine. A means to isolate the NifB enzyme for characterization has been developed through use of a GST-fusion tag. …

Early Transition Metal Ccc-Nhc Pincer Complexes: Synthesis, Characterization, And Catalysis, Theodore Rudy Helgert

Electronic Theses and Dissertations

The previously reported amine elimination methodology for the metalation of CCC-NHC pincer ligand precursors has been extended to other early-transition metals and ligands. Specifically, synthetic results for the preparation of imidazole based CCC-NHC pincer Ti (IV), CCC-NHC pincer Ta (V) will be discussed. In addition, the synthesis of a new triazole based CCC-NHC pincer ligand precursor and its metalation with Ta (V) will be presented. Coordination sphere manipulation of the new pincer complexes using TMSCl for the Ti complex and lithium t-butylamide for the Ta complexes is also discussed. The reaction of the initial Ta CCC-NHC complex with lithium t-butylamide …

Method Development Using Laser Ablation And Solution Icpms And Their Application In Environmental Science And Forensic Provenance Studies, Kaixuan Bu

Electronic Theses and Dissertations

Inductively coupled plasma mass spectrometry (ICPMS) is an analytical technique that can be used to determine multiple elements and isotope ratios in a wide variety of samples. In this work, four projects are described that involve the method development using laser ablation (LA) and solution-based ICPMS and their application in environmental science and forensic (provenance) investigations. In the first project, plutonium (Pu) concentrations and 240Pu/ 239Pu atom ratios were measured in kelp, lichen, aquatic moss, and horse mussel collected on or near Amchitka Island, a former nuclear test in Alaska, and at a background site. The Pu in terrestrial and …

An Adhesive Vinyl-Acrylic Electrolyte And Electrode Binder For Lithium Batteries, Binh Tran

Electronic Theses and Dissertations

This dissertation describes a new vinyl-acrylic copolymer that displays great potential for applications in lithium ion batteries by enabling processes that are novel, faster, safer, and less costly than existing manufacturing methods. Overall, the works presented are based on tailored chemical synthesis directly applied to lithium ion battery manufacturing. Current manufacturing methods still have many flaws such as toxic processes and other time consuming if not costly steps. Understanding the chemistry of materials and processes related to battery manufacturing allows the design of techniques and methods that can ultimately improve the performance of existing batteries while reducing the cost. Chapter …

Trace Contaminant Control: An In-Depth Study Of A Silica-Titania Composite For Photocatalytic Remediation Of Closed-Environment Habitat Air, Janelle Coutts

Electronic Theses and Dissertations

This collection of studies focuses on a PCO system for the oxidation of a model compound, ethanol, using an adsorption-enhanced silica-Ti02 composite (STC) as the photocatalyst; studies are aimed at addressing the optimization of various parameters including light source, humidity, temperature, and possible poisoning events for use as part of a system for gaseous trace-contaminant control system in closed-environment habitats. The first goal focused on distinguishing the effect of photon flux (i.e., photons per unit time reaching a surface) from that ofphoton energy (i.e., wavelength) of a photon source on the PCO of ethanol. Experiments were conducted in a bench-scale …

Investigation Of A Novel Magnesium And Acidified Ethanol System For The Degradation Of Persistent Organic Pollutants, Phillip Maloney

Electronic Theses and Dissertations

For centuries chemists have sought to improve humankind’s quality of life and address many of society’s most pressing needs through the development of chemical processes and synthesis of new compounds, often with phenomenal results. Unfortunately, there also are many examples where these chemicals have had unintended, detrimental consequences that are not apparent until years or decades after their initial use. There are numerous halogenated molecules in this category that are globally dispersed, resistant to natural degradation processes, bioaccumulative, and toxic to living organisms. Chemicals such as these are classified as persistent organic pollutants (POPs), and due to their negative environmental …

Mechanochemistry For Solid-State Syntheses And Catalysis, David Restrepo

Electronic Theses and Dissertations

Traditional methods of synthesizing inorganic materials, such as hydrothermal, sol-gel, calcination and grinding steps, can typically require use of high temperatures, expensive precursors or use of solvents. Because of the energy-intensive nature or environmental impact these techniques, there is a push, especially from an industrial perspective, to move towards greener approaches. Mechanochemistry is a solvent-free alternative technique that can be used to synthesize a variety of materials under ambient conditions. Due to this, there is an increase in attention towards the use of this approach in both solid-state inorganic and organic chemistry. This dissertation reports the mechanochemical synthesis of a …

Solid Phase Extraction Room Temperature Fluorescence Spectroscopy For The Direct Quantification Of Monohydroxy Metabolites Of Polycyclic Aromatic Hydrocarbons In Urine Samples, Korina Jesusa Calimag

Electronic Theses and Dissertations

Polycyclic aromatic hydrocarbons (PAH) are important environmental pollutants generally formed during incomplete combustion of organic matter containing carbon and hydrogen. Introduced into the human body by adsorption through the skin, ingestion or inhalation, the biotransformation processes of PAH lead to the formation of multiple metabolites. Due to the short elimination lifetime from the body, the quantitative determination of monohydroxy-PAH (OH-PAH) in urine samples provides accurate information on recent exposure to environmental PAH. Urine analysis of OH-PAH with established methodology relies on sample clean-up and pre-concentration followed by chromatographic separation and quantification. Although chromatographic techniques provide reliable results in the analysis …

Remediation Of Polychlorinated Biphenyl (Pcb) Contaminated Building Materials Using Non-Metal And Activated Metal Treatment Systems, Tamra Legron-Rodriguez

Electronic Theses and Dissertations

PCBs are recalcitrant compounds of no known natural origin that persist in the environment despite their ban by the United States Environmental Protection Agency in 1979 due to negative health effects. Transport of PCBs from elastic sealants into concrete, brick, and granite structures has resulted in the need for a technology capable of removing these PCBs from the materials. This research investigated the use of a nonmetal treatment system (NMTS) and an activated metal treatment system (AMTS) for the remediation and degradation of PCBs from concrete, brick, and granite affixed with PCB-laden caulking. The adsorption of PCBs onto the components …

Enhanced Two-Photon Absorption In A Squaraine-Fluorene-Squaraine Dye: Design, Synthesis, Photophysical Properties, And Solvatochromic Behavior, William Moreshead

Electronic Theses and Dissertations

The discovery of any new technology is usually accompanied by a need for new or improved materials which make that technology useful in practical applications. In the case of two-photon absorption (2PA) this has truly been the case. Since its first demonstration in 1961, there has been an ever increasing quest to understand the relationships between two-photon absorption and the structure of two-photon absorbing materials. This quest has been motivated by the many applications for 2PA which have been reported, including fluorescence bioimaging, 3D microfabrication, 3D optical data storage, upconverted lasing, and photodynamic therapy. The work presented in this dissertation …

Development Of Micro Volume Dna And Rna Profiling Assays To Identify The Donor And Tissue Source Of Origin Of Trace Forensic Biological Evidence, Brittany Morgan

Electronic Theses and Dissertations

In forensic casework analysis it is necessary to obtain genetic profiles from increasingly smaller amounts of biological material left behind by perpetrators of crime. The ability to obtain profiles from trace biological evidence is demonstrated with so-called ‘touch DNA evidence’ which is perceived to be the result of DNA obtained from shed skin cells transferred from donor to an object or person during physical contact. However, the current method of recovery of trace DNA involves cotton swabs or adhesive tape to sample an area of interest. This "blindswabbing" approach may result in the recovery of biological material from different individuals …

Squaraine Dyes, Design And Synthesis For Various Functional Materials Applications, Yuanwei Zhang

Electronic Theses and Dissertations

This dissertation contains the synthesis and characterization of squaraine based new functional materials. In the first part of this thesis work, a water soluble benzothiazolium squaraine dye was synthesized with pyridium pendents, and controlled aggregation properties were achieved. After formation of partially reversible J-aggregation on a polyelectrolyte (poly(acryl acid) sodium salt) template, the nonlinear, two-photon absorption cross section per repeat unit was found to be above 30-fold enhanced compared with nonaggregate and/or low aggregates. Using a similar strategy, sulfonate anions were introduced into the squaraine structure, and the resulting compounds exhibited good water solubilities. A ‘turn on’ fluorescence was discovered …

Immobilized Bis-Indenyl Ligands For Stable And Cost-Effective Metallocene Catalysts Of Hydrogenation And Polymerization Reactions, Thomas Max Simerly

Electronic Theses and Dissertations

Reactions of catalytic hydrogenations and polymerizations are widely used in industry for manufacture of fine chemicals, pharmaceuticals, and plastics. Homogeneous catalysts for the processes that have low stability and their separation is difficult. Therefore, the development of new highly active and stable catalysts for hydrogenations and polymerizations is a necessity. The objective of this research was the development of a strategy for immobilization of heterogeneous metallocene catalysts. First, a methodology of immobilization of bis-indenyl ligands on the surface of mesoporous silica gel was designed. Four bis-indenyl ligands containing functionalized tethers of various lengths with terminal alkene groups were synthesized. All …

Design And Synthesis Of Novel Fluorescent Nucleoside Analogues, Nada Abdulnasir Elsharif

Electronic Theses and Dissertations

This project aimed to obtain a set of fluorescent nucleoside analogues that closely resemble cytosine with extending the aromatic surface (extended conjugation) for enhance the photophysical properties. In addition to synthesize new fluorescent nucleoside analogues and evaluate their photophysical properties, this project aimed to understand the effects of donor substituent on the tC photophysical properties.

The main goal of these studies is to develop highly fluorescent nucleotide analogues. We first were looking to synthesize tC^C fluorescent nucleotide with the pyrimido[4,5-b]quinolone. In this part, 2-chloro-3- formylquinoline was easily prepared, yet the cyclization of 2-chloro-3- formylquinoline with urea or guanidine HCl …

Studies On The Preparation, Immobilization, And Luminescence Properties Of Zinc Oxide (Zno)Quantum Dots, Yasemin Hakat

Electronic Theses and Dissertations

Quantum dots are a part of very important our technological future because of their intriguing and useful properties. These properties are different in character from those of the corresponding bulk material. Quantum dots are inorganic artificial semiconductor nanocrystal whose electrons influence their physical and chemical properties. Zinc oxide quantum dots were synthesized through an ethanol based precipitation via colloidal synthesis method at various pH values. Various emission colors were obtained because the excited quantum dots of various sizes emitted specific wavelengths of light. The emission spectra indicated that the pH dependent quantum dots were successfully synthesized. Zinc oxide quantum dots …

Exploration Of The Chemistry Of Alkynes And Selectfluor : Search For Cytotoxic Agents From The Amazonian Rainforest., Zhuang Jin

Electronic Theses and Dissertations

Vicinal dithioethers and alkenyl thioethers were synthesized under environmentally friendly conditions using alkyne and thiol in water. Alkynes were also used to develop a multibond-fonning reaction that fonned cyclic ketones or ketoesters through a goldcatalyzed intramolecular oxygen transfer isomerization of 2-alkynyl-l ,5-diketones or 2- alkyny 1-5 -ketoesters. The investigation of Selectfluor chemistry yielded a highly stereoselective synthesis of fluoroalky (E)-a,ß-unsaturated ketones from allenyl esters, through a gold-catalyzed rearrangement that produced an intennediate dienyl ester. When Selectfluor was combined with copper, it produced two oxidative systems, F-TEDA-BF4 and F-TEDAPF 6, both of which efficiently converted amides into imides at room temperature …

Plasma Spectroscopic Techniques Applied To Biological And Environmental Matrices, Morgan Steele Schmidt

Electronic Theses and Dissertations

The purpose of this research was to apply the use of direct ablation plasma spectroscopic techniques, including spark-induced breakdown spectroscopy (SIBS) and laser-induced breakdown spectroscopy (LIBS), to a variety of environmental matrices. These were applied to two different analytical problems. SIBS instrumentation was adapted in order to develop a fieldable monitor for the measurement of carbon in soil. SIBS spectra in the 200 nm to 400 nm region of several soils were collected, and the neutral carbon line (247.85 nm) was compared to total carbon concentration determined by standard dry combustion analysis. Additionally, Fe and Si were evaluated in a …

Electrochemical Studies Of Nanoscale Composite Materials As Electrodes In Direct Alcohol Fuel Cells, Jordan Anderson

Electronic Theses and Dissertations

Polymer electrolyte membrane fuel cells (PEMFCs) have recently acquired much attention as alternatives to combustion engines for power conversion. The primary interest in fuel cell technology is the possibility of 60% power conversion efficiency as compared to the 30% maximum theoretical efficiency limited to combustion engines and turbines. Although originally conceived to work with hydrogen as a fuel, difficulties relating to hydrogen storage have prompted much effort in using other fuels. Small organic molecules such as alcohols and formic acid have shown promise as alternatives to hydrogen in PEMFCs due to their higher stability at ambient conditions. The drawbacks for …

Structural Polymorphism In Tau Filaments: An Implication For Neurodegenerative Diseases, Ayisha Siddiqua

Electronic Theses and Dissertations

Tau filaments are the pathological hallmark of >20 neurodegenerative diseases including Alzheimer's disease, Pick's disease, and progressive supranuclear palsy. In the adult human brain, six isoforms of tau are expressed that differ by presence or absence of the second of the four semiconserved repeats. As a consequence, half of the tau isoforms have three repeats (3R tau), whereas the other half has four repeats (4R tau).

Site-directed spin labeling of recombinant tau in conjunction with electron paramagnetic resonance spectroscopy was used to obtain structural insights into tau filaments. The studies showed that the filaments of 4R tau and 3R tau …

Tandem Mass Spectrometric Analysis Of Ammonium And Sodium Oligoperoxide Adducts With The Application Of Two-Dimensional Correlation Spectroscopy And Computational Chemistry, Jessica Lynne Frisch

Electronic Theses and Dissertations

Oligoperoxides, H[OO(CH3)2C]nOOH, are formed as side products in the synthesis of the primary high explosive triacetone triperoxide (TATP). Previous tandem mass spectrometry (MSn ) experiments using a quadrupole ion trap reported that the openchained oligoperoxide adducts of ammonium or sodium resulted in different product ions in the mass spectra. Dissociation mechanisms were previously proposed based on MSn experiments, where n > 2; however, a dissociation pathway achieved by an MSn experiment, where n > 2, may not necessarily be the same pathway achieved in an MS2 experiment. For this dissertation research, the collision induced dissociation pathways were investigated for the open-chained oligoperoxides …

The Behavior Of Cerium Oxide Nanoparticles In Polymer Electrolyte Membranes In Ex-Situ And In-Situ Fuel Cell Durability Tests, Benjamin Pearman

Electronic Theses and Dissertations

Fuel cells are known for their high efficiency and have the potential to become a major technology for producing clean energy, especially when the fuel, e.g. hydrogen, is produced from renewable energy sources such as wind or solar. Currently, the two main obstacles to wide-spread commercialization are their high cost and the short operational lifetime of certain components. Polymer electrolyte membrane (PEM) fuel cells have been a focus of attention in recent years, due to their use of hydrogen as a fuel, their comparatively low operating temperature and flexibility for use in both stationary and portable (automotive) applications. Perfluorosulfonic acid …

Design, Synthesis, And Biological Evaluation Of Novel Polyamine Transport System Probes And Their Application To Human Cancers, Aaron Muth

Electronic Theses and Dissertations

The mammalian polyamine transport system (PTS) has been of interest due to its roles in cancer and maintaining cellular homeostasis. Polyamines are essential growth factors which are tightly controlled via a balance of biosynthesis, metabolism, import, and export. This work focused on the development and biological testing of polyamine transport probes to help understand the molecular requirements of the PTS. This was mediated through the use of a CHO (PTS active) and CHO-MG* (PTS deficient) screen, where compounds demonstrating high toxicity in CHO and low toxicity in CHO-MG* were considered PTS selective. The first chapter focused on the development of …

Use Of An Activated Magnesium/Cosolvent System For The Desorption And Degradation Of Polycyclic Aromatic Hydrocarbons And Their Oxygenated Derivatives In Contaminated Soils, Marc Elie

Electronic Theses and Dissertations

The contamination of soils, with polycyclic aromatic hydrocarbons (PAHs), remains a widespread environmental concern. In the past two decades, many physical, chemical and biological methods have been developed and evaluated for the degradation of PAHs. However, due to their low aqueous solubility, high sorption affinity, hydrophobicity and recalcitrance, the environmental remediation of PAHs in soil continues to be economically challenging. In addition to PAH contamination, the presence of oxygenated derivatives of PAHs (OPAHs), in soils, has increasingly become a concern due to their greater toxic properties compared to parent PAH compounds. To date, no investigations on OPAH-remediation methods have been …

Optimization And Development Of In Vitro Bioassays To Determine Structure-Activity Relationships For Cannabinoid Receptor 1 And Cannabinoid Receptor 2, Afeef Husni

Electronic Theses and Dissertations

Cannabis has been around for thousands of years and has been used recreationally, medicinally, and for fiber. Over 400 compounds have been isolated from Cannabis sativa with approximately 100 being cannabinoids. Of those 100 compounds, Δ9-THC has been determined as the primary constituent, which is also responsible for the psychoactivity associated with Cannabis. Along with Δ9-THC, cannabidiol has been studied in depth for its therapeutic effects. This has currently been the focus of many researchers since cannabidiol does not cause psychotropic effects.

Cannabinoid receptors belong to the large superfamily of G protein-coupled receptors (GPCRs). Approximately 30% of marketed drugs target …

Elemental And Isotopic Analysis Of Sediments From Oxbow Lakes In The Mississippi Delta, Pragya Chakravarty

Electronic Theses and Dissertations

No abstract provided.

Synthesis And Characterization Of Nickel Complexes With Relevance To Nickel Acireductone Dioxygenase And Nickel Superoxide Dismutase, Margo Nicole Montgomery

Electronic Theses and Dissertations

This research presents an investigation of synthetic model complexes with relevance to the active site of Ni(II) acireductone dioxygenase (Ni-ARD) and Ni(II) superoxide dismutase (Ni-SOD). Acireductone dioxygenases (ARDs) are a unique set of enzymes found in the methionine salvage pathway that catalyze the oxidation reaction of acireductone (1, 2-dihydroxy-3-oxo-5-(methylthio)pent-1-ene). These enzymes share a compolypeptide sequence but bind different metal ions, Ni2+ or Fe2+, at the active site. The Ni-ARD enzyme is responsible for the off pathway shunt in the pathway. Using the tridentate nitrogen donor ligands hydrotris(3,5-dimethyl-1-pyrazolyl)borate (Tp*) and the newly developed tris(1, 2-dimethyl-4-imadozyl)carbinol, (4-TICMe, Me) several reactions involving the …

Theoretical And Spectroscopic Studies Of Molecular Systems For Charge Transfer And Energy Storage And Transfer, Debra Scardino

Electronic Theses and Dissertations

Efficient charge transfer and energy storage and transfer have become increasingly important in many areas of research and development. This is especially true for the development of optoelectronic devices, molecular electronics, and solar voltaic cells. Characterization of the photophysical properties of new molecular systems for these applications has emerged as an important field of research. Many molecular building blocks have been developed and understanding the properties of these systems at a fundamental level is essential for their successful implementation. This dissertation focuses on experimental and theoretical studies of some of these newly-developed molecular systems. Oxygen substituted dihydrobenzvalene is studied theoretically …

On The Nature Of Weak Intermolecular Forces: A First Principles Approach To Hydrogen Bonding And Pi-Type Interactions, Kari Lorene Copeland

Electronic Theses and Dissertations

Computational quantum chemistry is a branch of chemistry that is based on quantum mechanics. In this field, chemical phenomena is represented in mathematical form and computers are used to provide numerical solutions to rigorous mathematical equations. Through this medium, the properties of atoms and molecules are calculated with high accuracy. Chapter 1 opens with a general discussion of science, the development of atomic theory and computational chemistry. Electronic structure theory is more extensively reviein Chapter 2. Hydrogen bonding and dispersion forces are defined in Chapter 3, and the procedures used to computationally study these type interactions are considered. Chapter 4 …