Physical Sciences and Mathematics Commons^™

Photochemical Reactions Of Optically Active Chiral And Achiral Organic Materials, Nicie Conley Murphy

Doctoral Dissertations

Sodium chlorate, NaClO₃, which crystallizes in the space group P2₁3, forms optically active crystals upon crystallization although the molecule itself is achiral. NaClO₃, has been shown to produce an asymmetric distribution of (+) and (-) crystals when crystallized from water while stirring. It has been discovered that beta or positron radiation can also induce asymmetric crystallization in NaClO₃ solutions. Like NaClO₃, achiral 4,4’-dimethylchalcone crystallizes in enantiomeric forms in the space group P2₁3. Kondepudi et al. provided evidence that stirred crystallizations of 4,4’-dimethylchalcone can induce a bimodal distribution of …

Interdisciplinary Approaches To New Chemical Analysis, David Lynn Rodman

Doctoral Dissertations

The primary focus of this dissertation is the development of new chemical analyses for inorganic, organic, and organometallic compounds. Interdisciplinary approaches combining analytical, polymer, inorganic, organic, and materials chemistry have been used to develop new analytical methods. Topics discussed in this dissertation include the development of a sol-gel based metal ion sensor, photochemical oxidation of a biomimetic Cr(III) complex, photochemical oxidation of organic ligands and other interferences in model Pd catalyst complexes, modified Fujiwara reactions for the detection of halogenated hydrocarbons, and the development of a controlled-release polymer for delivery of reagents needed for chemical sensing applications.

Structural And Spectroscopic Studies Of Transition Metal Organometallic And Coordination Complexes With Reference To Catalysis, Megan Taliaferro Bragg

Doctoral Dissertations

Inorganic chemistry encompasses a variety of topics and in many ways, these advances affect a wider sphere of chemists than purely inorganic and progress in this field is interesting to many scientists. The developments presented in this dissertation are significant as they affect three issues: catalytic reactivity, ligand fluxionality, and catalyst development. Catalysis affects industrial profit, pharmaceutical development, agrochemical synthesis, spectroscopy, enzymatic activity, and polymerization.

Progress in certain areas such as the [Cp*Rh(TsDPEN)] (TsDPEN = p-toluenesulfonyldiphenylethylenediamine) has lead to a moiety that is a powerful and efficient catalyst for the reduction of C=N bonds. The precise mechanism of the …

The Development Of Building Block Methodologies To Produce Nanostructured Heterogeneous Catalysts By Design, Jason Curtis Clark

Doctoral Dissertations

Building block methods were successfully developed to demonstrate the potential of this approach to synthesizing nanostructured heterogeneous catalysts by design. The octa(trimethyltin) cuboctameric spherosilicate, Si₈O₂₀(SnMe₃)₈, was used as the building block for the synthesis of these materials. The solid state structure of this building block was characterized and compared to other solid state structures of Si₈O₁₂ containing compounds. These studies showed that this building block is composed of rigid tetrahedral units connect through a flexible siloxy bridge. The trimethyltin functionality present on this molecular precursor will react with metal …

Cloning, Overexpression, Purification And Characterization On N-Terminal Metal Binding Domains 5 And 6 Of Wilsons Disease Protein, David Achila

Masters Theses

Wilsons disease is an autosomal recessive disorder of copper metabolism which results from mutations in the gene encoding for Wilson disease protein (WDP). The cytosolic N-terminus of WDP comprises six metal binding domains each containing a conserved metal binding motif, GMXCXXC. The contribution of these metal binding domains to copper homeostasis is poorly understood. We have cloned, expressed and purified residues 485 to 633 corresponding to N-terminal metal-binding domains 5 and 6 of WDP (WD5-6). Two of the 3 disease causing mutations in the N-terminal metal binding domains of WDP occur one in each of these domains and the two …

Synthesis Of 123-Iodine Labeled Rofecoxib Analogues: Potential Nuclear Medicine Imaging Agents, Brandy U. Belue

Masters Theses

Single photon emission computed tomography (SPECT) is a medical imaging technique which provides three-dimensional images ofliving systems after introduction ofa radiolabeled pharmaceutical. Rofecoxib (4-[ 4-methylsulphonylphenyl]-3phenylfuran-2(SH)-one) is an inhibitor of the cycloxygenase-2 enzyme, an enzyme which has been found to promote cancer cell growth. The synthesis of a no-carrier-added iodine-123 labeled rofecoxib derivative is potentially of value for the detection of cancer utilizing SPECT.

Iodine-123 labeled -(3-Iodophenyl)-4-(methanesulfonylphenyl)-SH furan-2-one, 1, and 3-(4-Iodophenyl)-4-(methanesulfonylphenyl)-5H-furan-2-one, 2, were prepared from the respective potassium organotrifluoroborate salts. The trifluoroborates were prepared from a simple six step pathway.

A Study Of How Precursor Key Concepts For Organic Chemistry Success Are Understood By General Chemistry Students, Patrick Gerard Meyer

Dissertations

This study examines college student understanding of key concepts that will support future organic chemistry success as determined by university instructors. During four one-hour individual interviews the sixteen subjects attempted to solve general chemistry problems. A think-aloud protocol was used along with a whiteboard where the students could draw and illustrate their ideas. The protocols for the interviews were adapted from the Covalent Structure and Bonding two-tiered multiple choice diagnostic instrument (Peterson, Treagust, & Garnett, 1989) and augmented by the Geometry and Polarity of Moleculessingle-tiered multiple choice instrument (Furió & Calatayud, 1996). The interviews were videotaped, transcribed, and coded …

A Microreactor System For Measuring Size Selectivity In Porous Wo3 Sensor Materials, Meng Lu

Electronic Theses and Dissertations

Our interest in studying reactions catalyzed by high surface area W0₃ powders is based on their potential application as the active material in sensors for low level (ppb) detection of flammable or toxic gases. A series of porous W0₃ powders with both meso- and micro-porosity have been synthesized by Waghe and Tripp. Preliminary results of the response of sensors fabricated from these materials indicated the possibility of size selectivity on the molecular scale. To provide support for the hypothesis of size selectivity and understand the reaction kinetics of alcohols over the new porous W0₃ powders for sensor …

Systems For Predicting Pitzer’S Ion-Interaction Model Parameters, Theresa Balderas Obias

Masters Theses

Pitzer's Ion-interaction Model had been widely used in predicting the non-ideal behavior of solution over a wide range of conditions for natural water systems. The model is successful only when there are sufficient parameters available. However, generating these needed parameters requires a great quantity of work and it would be advantageous to be able to predict the Pitzer's parameters for salt systems when there is no data available.

This research entailed the development of ionic radii dependent equations for Pitzer's binary ion-interaction parameters β_MX⁽⁰⁾, β_MX⁽¹⁾, β_MX⁽²⁾, and C^ϕ_MX . …

The Role Of Phosducin-Like Protein And The Cytosolic Chaperonin Cct In G Beta Gamma Dimer Assembly, Ting Hu

Theses and Dissertations

Phosducin-like protein (PhLP), a G protein beta gamma subunit dimer binder and G protein signaling regulator, was suggested to regulate the activity of cytosolic chaperonin CCT by their high affinity interaction. In the present study, the three-dimensional structure of PhLP:CCT complex has been solved by cryoelectron microscopy. PhLP was found to bind only one of the chaperonin rings with both N- and C-terminal domains. It spans the central folding cavity of CCT and interacts with two opposite sides of the top apical region, inducing the constraining of the entry of the folding cavity. These findings support a putative role of …

Palladium-Imidazolium Carbene Catalyzed Heck Coupling Reactions And Synthesis Of A Novel Class Of Fluoroanthracenylmethyl Ptc Catalysts, Jiuqing Zhang

Theses and Dissertations

Palladium catalyzed Heck coupling with aryl and alkenyl halides has become a powerful means of carbon-carbon bond formation. This standard synthetic method has been developed to a high level of utility using various catalysts, conditions and substrates. Yet significant drawbacks remain, including poor reactivity, the need for high temperatures and base, limited substrate generality, and selectivity. Mixed products often suffer from olefin migration following insertion. N-Heterocyclic carbenes (NHC) have proven to be electron-rich donors which provide higher stability and reactivity than phosphines. In a previous paper reported by our research group the imidazolium-palladium carbene has proven to be highly efficient …

Total Syntheses Of (+)-Geldanamycin, (-)-Ragaglitazar, And (+)-Kurasoin A And Phase-Transfer-Catalyzed Asymmetric Alkylation, Erik J. Hicken

Theses and Dissertations

Geldanamycin possesses various biological activities as seen in the NCI 60 cell line panel (13 nM avg., 70 nM SKBr-3 cells). The predominant mode of action providing these unique results arises from the ability of geldanamycin (GA) to bind to the chaperone heat shock protein 90 (Hsp90). Despite its complicated functionality, the first total synthesis of GA was accomplished, which included two new reactions developed specifically to address the stereochemical features. The final step in the synthesis of GA was a demethylation-oxidation sequence to generate the desired para-quinone. This step could only be accomplished with HNO3/AcOH, producing GA in …

Specific Heat And Thermodynamic Properties Of Metallic Systems: Instrumentation And Analysis, Brian E. Lang

Theses and Dissertations

A small-scale adiabatic calorimeter has been constructed as part of a larger project to study nano-particles and to facilitate specific heat measurements on samples where it is difficult to obtain enough material to run on the current large-scale adiabatic apparatus. This calorimeter is designed to measure sample sizes of less than 0.8 cc over a temperature range from 13 K to 350 K. Specific heat results on copper, sapphire, and benzoic acid show the accuracy of the measurements to be better than ±0.4% for temperatures higher than 50 K. The reproducibility of these measurements is generally better than ±0.25%. Experimental …

Microcapsule Biosensors Based On Competitive Binding And Fluorescence Resonance Energy Transfer Assays, Swetha Chinnayelka

Doctoral Dissertations

Fluorescent sensing systems offer the potential for minimally invasive monitoring with implantable devices, but they require carrier technologies that provide suitable immobilization, accessibility, and biocompatibility while maintaining adequate response characteristics. Towards the development of this goal, a general design of a biosensor with the capability of detecting different metabolites was investigated. The approach is based on the encapsulation of a competitive binding assay in microcapsules and monitoring the changes in fluorescence resonance energy transfer (FRET) in the presence of analyte. To experimentally demonstrate this type of sensing system, glucose was chosen as the model target analyte. The design, fabrication, and …

Development And Application Of A Gg-Irms Reductive Pyrolysis Reactor Interface For The Δ34S Determination Of Sulfur In Individual Organic Compounds, N. Deborah Hewlett

Chemistry & Biochemistry Theses & Dissertations

The incorporation of sulfur into sedimentary organic matter is an important aspect of organic carbon preservation. A better understanding of the sulfur cycle and the formation of organo-sulfur compounds are necessary if we are to better understand the interaction of biogeochemical cycles of C, N, O, H. and S. Currently, the determination of ³⁴S/³²S in organic matter is limited to bulk organic samples. The sulfur isotopic analysis of individual organo-sulfur compounds within the sediments should allow for a more complete understanding of the sulfur cycle and the processes which lead to sulfur incorporation into organic matter. This …

Natural And Synthetic Viniferins Associated With The Grapevine Disease Young Vine Decline, David Michael Mcginnis

Chemistry & Biochemistry Theses & Dissertations

Grapevine disease has been thc subject of intense research amongst viticulturists over the last few decades, especially during the 1990's. There has been discoveries that suggest grapevine disease is commonly caused by fungal pathogens. One of the most common fungi that the vine may become infected by is known as Botrytis cinerea. B. cinerea is capable of attacking the grapevine which in turn will lead to bunch rot in the grape clusters. This disease has been researched in great detail during the past several years and is one of only few microorganisms that have actually been identified. Phaeoacremrmium chnlmydospnrum …

Polymer Microchips For Capillary Electrophoresis And Electric Field Gradient Focusing Of Biomolecules, Ryan Thomas Kelly

Theses and Dissertations

Polymeric materials have seen increasing use as microfluidic device substrates due to their low cost and the simplicity of templated fabrication procedures. I showed that poly(methyl methacrylate) (PMMA) microdevices could be enclosed in a boiling water bath, which allowed the seal to form more quickly than in conventional approaches, and enabled microchannels to remain hydrated throughout the bonding process. Microchip capillary electrophoresis (µ-CE) devices were fabricated using water-based enclosure, and a mixture of fluorescently labeled amino acids was separated in 30 s in these microchips. To create more robust capillary electrophoresis (CE) microdevices with improved separation performance, phase-changing sacrificial materials …

An Acyl Radical Cascade Model For The Total Synthesis Of Lyconadin A, Seth W. Grant

Theses and Dissertations

Lyconadin A (1) is a structurally unique Lycopodium alkaloid with antitumor properties, isolated from the club moss Lycopodium complanatum. We are developing a synthetic route to 1 based on a novel 7-exo-trig/6-exo-trig acyl radical cascade cyclization. The synthesis of model acyl radical cascade precursor 23 will be presented. Key features of this synthesis include the suppression of competing elimination during the alkylation of a hindered phenethyl bromide and the use of a lactone as a precursor to a compound bearing two differentially protected primary alcohols. An account of our studies on the model acyl radical cascade cyclization (23 to 24 …

Structure Elucidation Of Bioactive Compounds Isolated From Endophytes Of Alstonia Scholaris And Acmena Graveolens, Nicholas James Hundley

Theses and Dissertations

Alstonia scholaris is an evergreen tree native to Southeast Asia and Australia. It is commonly used as a medicinal plant throughout these regions. In the present study, an endophyte of the genus Xylaria was isolated from a stem of Alstonia scholaris, its mycelia and exudate extracted, and the extract assayed for growth inhibition of HeLa cancer cells in vitro. Several known compounds were isolated and identified based on NMR, infrared, and mass spectral data. The compounds identified are 19,20-epoxycytochalasin C; 19,20epoxycytochalasin D; and xylobovide. Two other compounds, fusaric acid and dehydrofusaric acid, were discovered in an endophyte of the Hypocreales …

Functionalization, Growth And Applications Of Single Wall Carbon Nanotubes, Yubing Wang

Dissertations

Because of their remarkable structural, mechanical and electrical properties, carbon nanotubes, and especially single wall carbon nanotubes (SWNTs), represent one of the most widely investigated materials today in the emerging field of nanotechnology. The development of oriented growth of SWNTs critical for applications, novel approaches for the creation of functional SWNTs, and applications of both as-prepared and chemically functionalized SWNTs for electrochemically-induced hydrogen storage, in-situ formation of new polymer and ceramic nanocomposites with SWNTs, and the fabrication and study for the first time, to the best of our knowledge, of a SWNT-based biofuel cell and self-powered biosensor, are the thrusts …

Effect Of Melatonin And Dopamine In Site Specific Phosphorylation Of Phosducin In Intact Retina, Arinzechukwu Okere Nkemdirim

Theses and Dissertations

Phosducin (Pdc) is a 28 kDa binding partner for the G protein beta gamma subunit dimer (G-beta-gamma) found abundantly in the photoreceptor cells of the retina and pineal gland. In the retina, light-dependent changes in cAMP and Ca2+ control the phosphorylation of Pdc at serine 73 and 54, respectively, which in turn controls the binding of Pdc to G protein beta gamma subunit dimer . G protein beta gamma subunit dimer binding has been proposed to facilitate light-driven transport of G protein beta gamma subunit dimer from the site of phototransduction in the outer segment of the photoreceptor cell to …

Cell Toxicity And Uptake Of Rrr-Alpha-Tocopheryl Polyethylene Glycol 1000 Succinate (Tpgs) By Various Cell Ines In Vitro., Christelle Komguem Kamga

Electronic Theses and Dissertations

This research focused on investigating and comparing the cytotoxicity and cellular uptake of RRR-alpha-tocopheryl polyethylene glycol succinate (TPGS, with that of alpha-tocopheryl succinate (α-TS). Both TPGS and α-TS are water-soluble forms of vitamin E with important clinical applications. Cytotoxicity assays with RAW 264.7 and LNCaP cells incubated overnight with TPGS or α-TS at concentrations ≥ 12.4 μM suggest that α-TS is more cytotoxic than TPGS. Macrophages were found to be more sensitive than LNCaP cells when treated with similar concentrations of α-TS. For both cell lines, most of the TPGS or α-TS taken up remained esterified after 24 hours. Our …

Electrochemical Remedy And Analysis For The Environment Based On The New Polymer-Dna Composite Material., Noor Feuza Hussain

Electronic Theses and Dissertations

In this work a new material, the conducting polymer-DNA composite, has been reported for the first time due to its promise in micro extraction, transfer, and release of cations under controlled potential conditions by using electrochemically assisted solid phase micro extraction (SPME). The Polypyrrole/DNA composite can be formed easily by oxidation of pyrrole monomers in the presence of chromosomal DNA by electropolymerization. Environmental significant pollutants such as Cd, Pb, Hg, Co, Zn, Cu, and Bi metal ions can be extracted from the aqueous solution and are able to be transferred to another medium defined as the release solution where the …

Cell Toxicology Study Of Rrr-Alpha-Tocopheryl Polyethylene Glycol 1000 Succinate (Tpgs)., Clarisse Sornsay Muenyi

Electronic Theses and Dissertations

This research focused on the cytotoxic properties of RRR-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) in transformed and cancerous cell lines. We used RAW264.7 macrophage and prostate cancer (LNCaP) cell lines in this study. TPGS caused cell death and decreased cell viability in a dose and time dependent manner. Cell death was evaluated fluorimetrically by employing the nucleic acid-binding fluorophore; propidium iodide. A colorimetric 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay was used to evaluate cell viability. Cell death can occur through necrosis or apoptosis. Our results suggested that TPGS triggered apoptotic cell death. Induction of apoptosis, as measured by caspase …

Potential Energy Surface Around The Tropylium Ion., Kenneth Wayne Bullins

Electronic Theses and Dissertations

The formation of the tropylium ion, C₇H₇⁺, in the mass spectrum of toluene is a chemical process that has been studied extensively in the past. The advances in computational power of personal computers have made the investigation of the pathway to form this ion and its subsequent decomposition feasible at a fairly high level of theory. The calculations that we performed were at the HF/6-31G (d, p) and the B3LYP/6-311++G (2d) levels. This work will show areas of the potential energy surface around the highly symmetric tropylium ion to give a glance of possible mechanisms …

Studies Directed Toward The Synthesis Of Acylated Phloroglucinols, Joseph Allen Burlison

Doctoral Dissertations

The synthesis and application of α-allenyl ketones directed toward the synthesis of polycyclic polyprenylated acylphloroglucinols are described. A functionalized α-allenyl ketone was synthesized in twelve steps starting from 2-methyl-2-cyclohexenome in 24% overall yield. The α’ stereocenter in the α-allenyl ketone was stereoselectively quaternized using a Tsuji allylation, Mukaiyama adol condensation sequence to afford C-1 functionalized allenyl cyclohexanone building blocks. A survey of acetals and reaction conditions for the Mukaiyama reaction suggested that 3-tert-butyldiphenylsiloxypropanal dimethyl acetal could be used, and indeed this reagent in the presence of TiCl₄∙Ti[OCH(CH₃)₂]₄ gave the aldol product …

Factors Affecting The Phase Separation Of Liquid Crystals From Acrylate-Based Polymer Matrices, Nathan Joseph Crawford

Doctoral Dissertations

The work presented in this dissertation covers the study of phase separation of small-molecule liquid crystals (LC's) from acrylate-based polymer matrices. These materials are used in the construction of polymer dispersed liquid crystals, or PDLC's, an emerging technology with applications ranging from privacy windows to photonic materials.

The first part of this study involves the determination of the effect of increasing polymer molecular weight on the solubility of the LC 4' -octyl-4-biphenyl carbonitrile, or 8CB, in poly(methyl methacrylate), or PMMA. Optical microscopy is used to determine the equilibrium phase diagrams for blends of 8CB and PMMA with weight-average polymer molecular …

Lanthanide Separation Using Rate-Controlled Solvent Extraction, Joey Edwin Dickson

Doctoral Dissertations

Solvent extractions of many of the lanthanide ions in both single ion and mixed ion environments have been carried out. These cations were first complexed with an aqueous complexing agent and were extracted with DEHPA (di-2 ethylhexylphosphoric acid) in an organic phase (kerosene). The experiments were designed to measure the rates of extraction in the hope that separation factors might be enhanced under non-equilibrium conditions. The complexing agents tried include ethylenediaminetetraacetic acid (EDTA), tetraethylenepentamine (tetraen), nitrilotriacetic acid (NTA), and diethylenetriamine (dien). These represent a hexadentate, pentadentate, tetradentate, and tridentate agent respectively. EDTA was determined to give the best results for …

Synthesis And Applications Of Monolithic Hplc Columns, Chengdu Liang

Doctoral Dissertations

Silica and carbon monolithic columns were synthesized and modified for liquid chromatography applications. Column configurations and cladding techniques were investigated in detail. Three novel approaches have been developed for the synthesis of bimodal porous rods. Out of these three methods, gel-casting was adopted for the synthesis of silica monoliths with ordered mesopores and uniform macropores; the use of colloidal templates and dual phase separation has been successfully implemented for the synthesis of carbon monoliths with well-controlled meso- and macro- porosities. The formation of mesopores in carbon materials has been further studied in the microphase separation of block copolymers. Electrochemical modification …

Tungsten Alkyl Alkylidyne And Bis(Alkylidene) Complexes. Their Unusual Inter-Conversion And Reactions With Phosphines, Dioxygen And Water, Laurel Anne Morton

Doctoral Dissertations

This dissertation focuses on the unique chemistry of d0 alkylidyne and bis (alkylidene) complexes with β-silicon atoms. The goals of this dissertation research were to prepare and characterize these new d0 transition metal complexes, to study their reactivities including thermodynamics and kinetics of the inter-conversion between the alkylidyne and bis(alkylidene) complexes, and to explore the mechanism of the reactions of O2 or water with d0 alkylidyne complexes.

A summary of the research in this dissertation is provided in Chapter 1.Chapter 2 reports the study of an unusual exchange between new alkyl alkylidyne and bis(alkylidene) complexes …