Physical Sciences and Mathematics Commons^™

Photochemical Applications To The Study Of Complexity Phospholipid Bilayer Environments, Christopher John Wohl Jr.

Theses and Dissertations

The physical and biophysical properties of a biological membrane model, phosphatidylcholine bilayers, were investigated using novel spiropyran/merocyanine molecular probes. The femtosecond to second dynamics of this system's photochemistry enabled bilayer viscosity and free volume to be studied over a broad time scale. Spiropyrans/merocyanines with different polarity were synthesized by changing the substitution of the indole moiety enabling determination of the trans-membrane properties of the bilayer. In addition, transient grating spectroscopy was used to study thermal energy transfer in phospholipid bilayers on a picosecond time scale.Femtosecond transient absorption spectroscopy was used to study the photo-induced spiropyran ring-opening and isomerization reactions that …

Quantitative Model For The Prediction Of Hydrodynamic Size Of Nonionic Reverse Micelles, Melissa A. Michaels

Theses and Dissertations

The sizes of nonionic reverse micelles were investigated as a function of the molecular structure of the surfactant, the type of oil, the total concentration of surfactant [NP], the ratio of NP4 to total surfactant (r), the water to surfactant molar ratio (ω), temperature, salt concentration, and polar phase. The basis of our investigation was nonylphenol polyethoxylates - NP4 and NP7. Micelle sizes were determined using dynamic light scattering (DLS). A central composite experimental design was used to quantitatively model reverse micelle size as a function of ω, [NP], and r. The model has demonstrated the capability of predicting the …

A Prelude To A Third Dimension Of The Periodic Table: Superatoms Of Aluminum Iodide Clusters, Naiche Owen Jones

Theses and Dissertations

Calculations have been carried out to investigate the stability and electronic structure of aluminum iodide clusters using first principles gradient-corrected density functional theory. Analysis of A113Ix-, A114Ix-, and A17I- clusters reveals that their stability is governed by the geometrically unperturbed A113-, A1142+, and A17+ units, respectively, that are demonstrated to constitute the compact cores of the clusters upon significant iodine content. The compact, icosahedral A113, icosahedral-like A1 14, and capped square bi-pyramid A17 superatom structures of the stable aluminum cores have an analogous electronic configuration to that of halogen, alkaline-earth, and alkaline atoms, respectively. Novel chemistry is demonstrated in superatoms, …

Gas Phase Studies Of Molecular Clusters Containing Metal Cations, And The Ion Mobility Of Styrene Oligomers, Edreese Housni Alsharaeh

Theses and Dissertations

This study is divided into three parts. Part I deals with the mechanism of the self-initiated polymerization (or thermal polymerization) of styrene in the gas phase. In this work, we present the first direct evidence for the thermally self-initiated polymerization of styrene in the gas phase. Our approach is based on on-line analysis of the gas phase Oligomers by mass-selected ion mobility. The mobility measurements provide structural information on the ionized oligomers based on their collision cross-sections (Ω) which depend on the geometric shapes of the ions. Theoretical calculations of possible structural candidates of the Oligomers ions are then used …

Experimental Studies On Nucleation, Nanoparticle's Formation And Polymerization From The Vapor Phase, Victor Maher Abdelsayed

Theses and Dissertations

This research is divided into three major parts. In part I, the critical supersaturations required for the homogeneous nucleation of 2,2,2-trifluorothanol (TFE) vapor have been measured over a temperature range (266-296 K) using an upward thermal diffusion cloud chamber (DCC). The measured supersaturations are in agreement with the predictions of both the classical and the scaled theory of nucleation. Moreover, the condensation of supersaturated TFE vapor on laser-vaporized magnesium nanoparticles has been studied under different experimental conditions, such as the supersaturation, the pressure and the electric field. In part II, the laser vaporization controlled condensation (LVCC) technique was used to …

Resonance Two Photon Ionization Study Of Binary Clusters Of Styrene With Polar Molecules, Hatem Ahmed Mahmoud

Theses and Dissertations

One-color resonance two-photo ionization (R2PI) spectra of mixed clusters of styrene molecule (S) with polar molecules [water (W), methanol (M), ethanol (E), and trifuoroethanol (T)] were measured through the S1←S0 transition of the styrene molecule. The spectra reveal a rapid increase in complexity with the number of polar molecules in the cluster, associated with van der Waal modes and isomeric forms. The spectral shifts of the cluster origins from the S1-S0 transition of the bare styrene molecule reflect the nature of the intermolecular interactions within the binary clusters. The obtained R2PI spectra xv were compared with the spectra of the …

Neural Networks In The Analysis Of Water-Soluble Sulfonylurea Herbicides Using An Lc/Ms, Joseph Michael Pompano

Theses and Dissertations

In this research, a hidden node pruning algorithm was developed for an artificial neural network (ANN) that automatically determined a more efficient size of the hidden layer, caused the ANN to resize itself, and then continued to train using a standard back-propagation algorithm. The hidden-node pruning algorithm was based on determining the number of significant eigenvalues present in the matrix of values produced by the hidden layer, starting with an excessive number of hidden nodes.

Eight sulfonylurea herbicides were used as the target analytes in this study. The ability of an ANN to simplify the sample preparation needed for analysis …

Interactions Among The Stationary Phase, The Mobile Phase, And The Solute In Liquid Chromatographic Systems, Zengbiao Li

Theses and Dissertations

Interactions among the stationary phase, the mobile phase, and the solute in liquid chromatography' have been studied. A strong dependence of the stationary phase properties on the mobile phase composition may arise from their interactions.

The solvatochromic comparison method, which can give estimates for the dipolarity-polarizability, the hydrogen-bonding acidity, and the hydrogen-bonding basicity of a solvent, represented by the solvatochromic parameters π⁺, α and β, respectively, was used to study the surface properties of silica in the presence of n-hexane-chloroform or n-hexane-ethyl ether mixtures. A high dipolarity- polarizability, a high hydrogen-bonding acidity, and a low hydrogen-bonding basicity …

Phosphorus Bearing Substrates In Ring Expansion Reactions, Bradley K. Norwood

Theses and Dissertations

A variety of substituted phosphonium salts, phosphorus ylides and phosphonates were studied to assess their utility in ring expansion reactions. The strategy involved formation of fused ring systems whose ring strain could be exploited to accomplish ring expansion to medium sized rings. β-Alkoxy vinylphosphonium salts were found to be unreactive with species such as the dimethylsulfoxonium methylide anion, Simmons-Smith type reagents. and carbenes in attempts to produce cyclopropyl phosphonium salts.

C-Alkylation of β-keto phosphorus ylides using haloalkanes bearing terminal groups that could be converted and reacted with the B-carbonyl, was also examined as a method for accessing strained rings bearing …

Resonance Raman Spectra Of Chloroperoxidase Reaction Intermediates, Ann Marie G. Sullivan

Theses and Dissertations

Chloroperoxidase is an enzyme that exhibits spectroscopic and structural properties similar to cytochrome P-450. Chloroperoxidase is studied using resonance Raman spectroscopy to characterize the reaction intermediates of the physiological mechanism, known as compounds I and II. Compound I is formed by a two electron oxidation of the resting enzyme and contains an Fe(IV) porphyrin ℼ cation radical. A one electron reduction of compound I produces the compound II intermediate which contains an oxy-ferryl [Fe(IV)=O] iron heme.

Chloroperoxidase is a heme enzyme of substantial interest because of its structural similarity to cytochrome P-450 and because of its diverse reactivity. Chloroperoxidase can …

Imide/Arylene Ether Copolymers, Brian J. Jensen

Theses and Dissertations

Three different series of imide/arylene ether block copolymers were prepared using two different imide blocks and two different arylene ether blocks. Block molecular weights studied were 3110 and 6545 g/mole for each block and all four combinations possible were prepared in each series. Also, several segmented copolymers were prepared by forming the imide segment and the copolymer in the presence of the pre-formed arylene ether block.

Two amine-terminated poly(arylene ether) blocks (ATPAE) were prepared by reacting 1,3-bis(4-fluorobenzoyl)benzene with either 2,2-bis(4-hydroxyphenyl)propane (BPA) or 9,9-bis(4-hydroxyphenyl)fluorene (BPF) and 4-aminophenol. Two anhydride-terminated poly(amic acid) blocks were prepared by reacting 4,4'-oxydianiline (ODA) or 1,3-bis(4-aminophenoxy-4’- benzoyl)benzene …

Reactions Of Substituted Pyridinium Salts With Cyanide; Formation And Metal Complexes Of 2,2'Bis (Hydroxymethyl)-4,-4'Bipyridine, Dorothy N. Eseonu

Theses and Dissertations

The unique combination of properties of bipyridinium salts and their use in biological systems, chemical reactions, and as herbicides in agriculture have made them a discovery of major international importance. The controversy about the position of attack of the cyanide ion on the pyridine ring and the discovery of the formation of unsubstituted bipyridinium salts from the reaction of pyridinium salt with cyanide ion opened a new area of research. The current work involved a study of reactions of substituted pyridinium salts with cyanide ion. The substituted pyridinium salts were prepared by the literature methods. The 2- and 3- cyanopyridinium …

Electrochemical And Surface Enhanced Resonance Raman Study Of Heme Proteins At Bare Metal Electrodes, David Edward Reed

Theses and Dissertations

Direct heterogeneous electron transfer reactions between horse heart cytochrome g_and silver electrodes were investigated by electrochemical and spectroelectrochemical methods. The kinetics of these reactions were established as being quasi-reversible, with a formal heterogeneous rate constant (k°'s,h) ranging between 0.18 - 1.5 x 10^-3 cm/s, for both polished and electrochemically roughened silver surfaces. Such reactions were stable and reproducible for over ten hours at room temperature. These results clearly demonstrate that neither electrode surface modification nor the inclusion of mediators is necessary to study electron transfer reactions of heme proteins at metal electrodes.

A crucial factor in obtaining the quasi-reversible …

Development Of Solid Substrate Luminescence And Chromatographic Techniques For Chemical Analysis, William J. Long

Theses and Dissertations

Room Temperature Phosphorimetry (RTP) is a sensitive and selective technique which is well suited to the analysis of compounds of environmental and pharmaceutical interests. Absolute sensitivity is generally in the low to subnanograrn range. Selectivity of this technique is due to the fact that only several hundred compounds phosphoresce at room temperature. In these studies attempts are made to gain a greater understanding of the phenomenon of solid substrate room temperature phosphorimetry and to extend the application range of the technique.

This goal is approached through several directions, all leading to a greater understanding of solid substrate luminescence in general, …

The Synthesis And Characterization Of Some Thermally Stable Polypyrazoles And Acetylene Terminated Aspartimides, John W. Connell

Theses and Dissertations

Reactions involving the nucleophilic addition cyclization to activated acetylenes have been employed as a novel route to moderate to high molecular weight polymers. Polypyrazoles (PI to P12) have been prepared from the Michael-type addition cyclization of various aromatic dihydrazines to aromatic dipropynones in m-cresol. The aromatic dihydrazines employed were 4, 4'-dihydrazinodiphenyl ether (4,4' -DHDPE), 4,4 '-dihydrazinodiphenylmethane (4, 4'-DHDPM), and 4, 4' -dihydrazinodiphenyl sulfone (4,4'-DHDPS). The dipropynone sutilized were 1,1’- (1,4-phenylene) bis (3-phenyl- 2-propyn-l-one), (l,4 -PPPO), 1,1’ - (1, 3-phenylene) bis (3 -phenyl- 2 -propyn-l-one), (1,3-PPPO), 1,1 '-(1,4 -phenylene) bis (2 -propyn- l-one), (1,4 -PPO), and 1,1’- (1,3 -phenylene) bis (2 …

Electrochemical Investigation Of The Effects Of Temperature, Ph, And Electrolyte On The Electron Transfer Reactions Of Cytochrome C, Kent Brian Koller

Theses and Dissertations

Spectroelectrochemical and electrochemical methods have been used to investigate the characteristics of heterogeneous electron transfer between cytochrome c and indium oxide electrodes. Direct electron transfer between cytochrome c and solid electrodes is of interest due to the interfacial character of electron transfer between the protein and its membrane-bound physiological redox partners. The conformation of ferricytochrome c is affected more by changes in temperature or pH than is its reduced form, ferrocytochrome c. This difference in conformational stability is attributed to the +1 charge of the heme in ferricytochrome c that is largely embedded in the hydrophobic interior of the enzyme. …

Chemical Studies On Oxomolybdenum(Vi,Iv) Complexes As Bioinorganic Models For The Molybdenum Oxidases, James Thomas Lyon Iii

Theses and Dissertations

The synthesis, characterization, and chemical properties of Mo(VI)o₂(5-X-SSP) and Mo(VI)o₂(5-X-SSE), (5-X- SSP²- = 2-((5-X-salicylidene)amino)benzenethiolate; 5-X- SSE^2- = 2-((5-X-salicylidene)amino)ethanethiolate; X = Br, Cl, H, CH₃O), which contain tridentate (ONS) Schiff base ligands is described. The chemical properties of these molybdenum complexes are compared with those which possess tridentate (ONO) Schiff base ligands. Cyclic voltammetry was used to obtain cathodic reduction potentials (E_PC) for the quasi-reversible reduction of the cis-dioxomolybdenum (VI) complexes. Although the reductions are quasi-reversible, trends are observed in E_PC both within series and when different series are …

Effects Of N-Substituents On The Polymerization Properties Of Maleimide, Dilip R. Abayasekara

Theses and Dissertations

The effect of the amide function and the carbethoxy function on the polymerization properties of maleimide are reported. The effects of these functions on homopolymerization and copolymerization (with styrene) were examined. These electron-withdrawing groups appeared to decrease the rate of homopolymerization and increase the rate of copolymerization.

N-carbamylmaleimide and N-carbethoxymaleimide were copolymerized with styrene in 1,4 -dioxane at 60.0° C at different feed ratios to high conversion. Copolymer composition, determined by elemental analysis and 1H NMR, indicated that while 1:1 copolymers were obtained with an equimolar feed ratio, the two systems were not alternating. It is of note that the …

Synthesis Gas Conversion With Zs M-5 Supported Ruthenium Catalysts, Robin Elizabeth Young Eaton

Theses and Dissertations

Some bifunctional ZSM-5 supported ruthenium catalysts (Ru/ ZSM-5) were prepared by an extraction technique employing Ru ₃(C0)₁₂ • The weight percentage Ru ranged from approximately 1% to 8% Ru as determined by Atomic Absorption Spectroscopy. Characterization data employing Infrared (IR) Spectroscopy, X-ray Powder Diffractometry (XRPD), X-ray Photoelectron Spectroscopy (XPS/ESCA), Ion-Scattering Spectrometry (ISS) and Chemisorption were obtained for the catalysts. The data indicated the presence of highly dispersed Ruo₂ particles of less than 60 A on the surface of the as-prepared (AP) catalysts. Calcination of the AP catalysts at 500°C for 24 h increased the particle size of …

Electrochemical Determination Of The Heterogeneous Electron Transfer Kinetics Of Soluble Spinach Ferredoxin, Charlene D. Crawley

Theses and Dissertations

The application of electrochemical techniques to biological systems has become an attractive method for characterizing the redox and electron transfer behavior of biomacromolecules. This study focuses on the role of soluble spinach ferredoxin (Fd) in photosynthesis where it functions as an electron carrier to membrane bound species in the plant chloroplast. An electrochemical model is used where in Fd now serves as a soluble redox species which undergoes oxidation and reduction via electron transfer at an electrode. This type of model is significant in that both the membrane and electrode reactive sites are characterized by charged bilayer interfacial regions which …

Interfacial Electrochemistry Of Cytochrome C And Myoglobin, Edmond F. Bowden

Theses and Dissertations

The interfacial electrochemistry of horse heart cytochrome c was studied at metal and metal oxide electrodes. Sperm whale myoglobin reactions at metal oxide and surface modified electrodes were also investigated. Emphasis was on the measurement and mechanistic interpretation of the heterogeneous electron transfer kinetic parameters for these electrode reactions.

The motivation for this study stems from the fact that some electron transfer proteins, e.g., cytochrome c, transfer electrons heterogeneously in physiological systems. Specific electrodes may, therefore, serve as suitable models for physiological surfaces. Electrode and membrane interfaces are both electrically charged and both have oriented hydration water layers.

The cyclic …

Direct Determination Of Pentachlorophenol By Differential Pulse Polarography, Albert L. Wade

Theses and Dissertations

Concern over environmental contamination leading to the introduction of pentachlorophenol into human and animal systems has resulted in the need for a rapid and direct method for determining trace concentrations of this highly toxic compound. A direct electrochemical procedure has been developed for determining trace conccentrations of this phenol dovm to 0.27 ppm. This method uses the electrochemical techniques of differential pulse polarography at the dropping mercury electrode, and differential pulse voltammetry at the carbon paste electrode to reduce pentachlorophenol for this determination. Cyclic voltammetry at the hanging mercury drop electrode has been used to characterize the reaction behavior of …

Synthesis Of Tcne And Tcnq Derivatives And The Preparation Of Conducting Polymers, Michael L. Runge

Theses and Dissertations

Tetracyanoethylene and tetracyanoquinodimethane were reacted with various N,N-dimethyl-a, w-alkyldiamines to produce TCNE and TCNQ diamino and monoamino derivatives. NMR and ir spectra of the monoamino derivatives, 1-(N,N-dimethyl-a,w-alkyldiamino)-1,2,2-tricyanoethylenes and 7-(N,N-dimethyl-a,w-alkyldiamino)-7,8,8-tricyanoquinodimethans, indicated that these compounds exhibited strong nitrogen-hydrogen-nitrogen intramolecular hydrogen bonding. This phenomenon was corroborated by molecular weight and preliminary x-ray analyses.

The 1,1-bis(N,N-dimethyl-a,w-alkyldiamino)-2,2-dicyanoethylene and 7,7-bis(N,N-dimethyl-a,m-alkyldiamino)-8,8-dicyanoquinodimethan derivatives were polymerized with a,m-alkyldibromides containing two to six methylene groups to produce the corresponding ionene polymers. Viscosity measurements of the polymers indicated that the TCNE copolymers were generally of higher molecular weight than the corresponding TCNQ copolymers.

The two polymer series were treated with lithium …

The Synthesis Of 4-Spiro-2-Aryloxazolines Of Potential Pharmacological Interest, Paul Waddell Collins

Theses and Dissertations

Numerous and diverse physiological actions are found among 2-oxazoline compounds. No reports of the synthesis or biological testing of 4-spiro-2-aryl-2-oxazolines were found in the literature. On the basis of the known pharmacological activities of certain aza- and diazaspirans, it was felt that 4-spiro-2-aryl-2-oxazolines should possess medicinal activity. In particular, it was reasoned that the combination in a bicyclic spiro structure of the 2-oxazoline ring with rings systems commonly found in synthetic antitussive compounds might result in active antitussive agents.

The aim of this research was the synthesis of a series· of 2-aryl-2-oxazoline-4-spirocyclopentanes and a series of 1'-methyl-2-aryl-2-oxazoline-4-spiro-4’-piperidines. Six members were …