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Spectroscopic Studies Of Bacterial Iron-Sulfur Proteins (Electron Paramagnetic Resonance, Magnetic Circular Dichroism)., Deborah Ellen Bennett
Spectroscopic Studies Of Bacterial Iron-Sulfur Proteins (Electron Paramagnetic Resonance, Magnetic Circular Dichroism)., Deborah Ellen Bennett
LSU Historical Dissertations and Theses
Iron-sulfur proteins play a vital role in metabolism; mediating such life-sustaining processes as aerobic and anaerobic respiration, nitrogen fixation, and photosynthesis. This work employs low temperature magnetic circular dichroism (MCD), electron paramagnetic resonance (EPR), and UV-visible spectroscopy to characterize the iron-sulfur clusters of the following bacterial proteins: Azotobacter vinelandii ferredoxinI, Thermus thermophilus ferredoxin, Escherichia coli nitrate reductase and the rubredoxin and ferredoxin from Clostridium pasteurianum. Novel 3Fe-xS clusters were identified in A. vinelandii FdI, T. thermophilus Fd, ferricyanide treated C. pasteurianum Fd, and E. coli nitrate reductase. The uniformity of the magnetic and electronic properties of these clusters in both …
Spectroscopy And Photochromism Of Triphenylformazan And Its Derivatives., Claudina Veas-Arancibia
Spectroscopy And Photochromism Of Triphenylformazan And Its Derivatives., Claudina Veas-Arancibia
LSU Historical Dissertations and Theses
The spectroscopic and photochromic characteristics of triphenylformazan and its derivatives were investigated. These derivatives were formed by adding substituents to the phenyl group attached to the carbon atom of the formazan ring or by replacing this phenyl group with a naphthyl group. Studies of the effect of the concentration, substituent, solvent and temperature on the absorption spectra of triphenylformazan were made. Molecular mechanics calculations were performed to generate two different geometries of triphenylformazan that were used in CNDO calculations to assign the electronic transitions observed in the absorption spectra. In contradiction to what was stated in earlier investigations, the results …
Palladium-Catalyzed Vinylic Substitution Of Aryl Halides On Polymeric Nitrogen Supports., Chia-Hsing Sun
Palladium-Catalyzed Vinylic Substitution Of Aryl Halides On Polymeric Nitrogen Supports., Chia-Hsing Sun
LSU Historical Dissertations and Theses
The structure of typical palladium complexes used as catalysts in organic synthesis is reviewed; particular attention is paid to the systematic study of palladium catalyzed vinylic substitution on a variety of aryl iodides and bromides (Heck-type vinylation). The general conditions of this process, i.e., a homogeneous catalyst operating at moderate temperature, which requires a proton acceptor to complete the catalyst cycle, are conducive to successful development of a polymer-bound catalyst. Using 4-picoline as a ligand under homogeneous Heck-type vinylation conditions. Morpholine is an adequate base to stabilize the catalytic picoline complex when aryl iodides are condensed with styrene. However, sodium …
Fluorescence Of Proanthocyanidin Polymers (Rotational Isomer)., Wolfgang Robert Bergmann
Fluorescence Of Proanthocyanidin Polymers (Rotational Isomer)., Wolfgang Robert Bergmann
LSU Historical Dissertations and Theses
The lifetimes and quantum yields of proanthocyanidins, monomers and dimers of catechin and epicatechin, were measured. The fluorescence quantum yield and lifetime of the monomers was three times greater in dioxane than in water. The fluorescence decay curves of catechin and epicatechin were found to be fit best by a monoexponential function. The fluorescence decay of dimers of epicatechin and catechin were best fit to a sum of two exponentials. The fluorescence decay curve of a bridged dimer, Procyaninidin A-2, in dioxane was best fit to a monoexponential function. The 400 MHz proton NMR spectra of Procyanidin B-1 decaacetate in …
New Types Of Lanthanide Complexes (Polyatomic Oxides)., Ishenkumba Albert Kasimbazi Kahwa
New Types Of Lanthanide Complexes (Polyatomic Oxides)., Ishenkumba Albert Kasimbazi Kahwa
LSU Historical Dissertations and Theses
Three new types of lanthanide (Ln) complexes, namely, the first examples of homodinuclear macrocyclic lanthanide complexes, novel binary and ternary gaseous polyatomic lanthanide oxides and new lanthanide oxalato complexes are described in chapters one, two and three respectively. The homodinuclear complexes are 2:2 condensation products of 2,6-diformyl-p-cresol and triethylenetetramine templated by Ln(NO(,3))(,3) and Ln(ClO(,4))(,3). The complexes are dimorphic, and are off-white (the more stable form) when they are obtained from dilute solutions and orange if they arise from more concentrated reactants. The complexes were characterized by elemental analysis, fast atom bombardment mass spectrometry (FAB MS), electronic absorption and IR spectroscopy, …
Spectroscopic Studies Of The Metal Centers In Hydrogenases And Carbon Monoxide Dehydrogenase (Nickel)., Isabel Cristina Zambrano
Spectroscopic Studies Of The Metal Centers In Hydrogenases And Carbon Monoxide Dehydrogenase (Nickel)., Isabel Cristina Zambrano
LSU Historical Dissertations and Theses
The biological activation of hydrogen is catalyzed by hydrogenases. An understanding of the mechanism by which hydrogenases act requires the elucidation of the nature and type of metal centers present in the enzymes. Room temperature UV-visible absorption, low temperature magnetic circular dichroism and electron paramagnetic resonance spectroscopies have been used to characterize the electronic and magnetic properties of the iron-sulfur and nickel centers in hydrogenases from Clostridium pasteurianum, Methanobacterium thermoautotrophicum, and Desulfovibrio gigas. In addition, another Ni-containing enzyme, carbon monoxide dehydrogenase from Clostridium thermoaceticum, and D. gigas Ni-substituted rubredoxin were investigated. The results provide evidence for the presence of conventional …
Spectral Studies Of Constituents Of Members Of The Family Asteraceae., Karla Ann Wilzer
Spectral Studies Of Constituents Of Members Of The Family Asteraceae., Karla Ann Wilzer
LSU Historical Dissertations and Theses
A phytochemical investigation of ten species of the genus Aster (Family Asteraceae, Tribe Astereae) was carried out. The study involved the following taxa from the southern region of the United States: A. adnatus, A. concolor, A. dumosus x lateriflorus (a hybrid), A. lateriflorus, A. patens, A. praealtus, A. spinosus, A. subulatus var. ligulatus and A. tenuifolius as well as A. umbellatus from Pennsylvania. The chemical analysis of A. praealtus provided umbelliferone and seven prenylated coumarins of which four were new natural products. A ten-carbon acetylenic compound was isolated from A. spinosus. (DELTA)('7)- Sterols were found in A. adnatus which is …
Modification Of Condensation Polymers., Cholticha Rungaroonthaikul
Modification Of Condensation Polymers., Cholticha Rungaroonthaikul
LSU Historical Dissertations and Theses
The degradation of poly oxy-1,4-phenylene(1-methylethylidene)-1,4-phenylene-oxy-1,4-phenylenesulfonyl-1,4-phenylene (poly(arylether sulfone)), 1, promoted by excess sodium methoxide was evaluated spectrophotometrically. Direct nitration of 1 with ammonium nitrate in trifluoroacetic anhydride produced poly(2-nitroarylether sulfone). The model segment 1 produced by reaction of 2,2'-bis(4-hydroxyphenyl)propane (bixphenol-A) with 7, was nitrated to obtain model segment of 2,2'-bis 3-nitro-4-(4-phenylsulfonyl phenoxy)-phenyl propane. The rate of polymer degradation was estimated by observing the increase in the concentration of phenolate end groups in the presence of sodium methoxide. It was shown that less than 6% degradation of the most reactive polymer, poly(2-nitroarylether sulfone) occurred after one week at 25(DEGREES)C. Comparison of the …
Laser Optogalvanic And Photoacoustic Studies Of Some Atoms And Small Molecules., Phillip Lamar Clancy
Laser Optogalvanic And Photoacoustic Studies Of Some Atoms And Small Molecules., Phillip Lamar Clancy
LSU Historical Dissertations and Theses
A device designed to perform laser optogalvanic (LOG) measurements on low pressure gases in an electrical discharge has been constructed. The device employs the unique combination of pulsed laser radiation in the visible range, and transverse excitation of a radiofrequency (RF) discharge to obtain high quality spectroscopic data on highly excited atomic and molecular species existing in an electrical discharge. The results of LOG studies on xenon, cesium, and nitrogen are reported. In addition to functioning as a sensitive LOG detector, it has been discovered that the RFLOG device serves admirably as a contractless transducer of the photoacoustic signal. When …
Spectroscopic Studies Of Mitochondrial Iron Sulfur Proteins (Succinate Dehydrogenase, Electron Paramagnetic Resonance, Fumarate Reductase)., Joyce Elaine Morningstar
Spectroscopic Studies Of Mitochondrial Iron Sulfur Proteins (Succinate Dehydrogenase, Electron Paramagnetic Resonance, Fumarate Reductase)., Joyce Elaine Morningstar
LSU Historical Dissertations and Theses
Aerobic respiration is linked to oxidative phosphorylation and involves a redox-linked proton translocation across the mitochondrial inner membrane. Deeper understanding of the mechanism of mitochondrial electron transport requires detailed characterization of the redox centers present in respiratory enzyme complexes. A combination of low temperature MCD spectra and magnetization data, with parallel EPR, CD, and UV-visible experiments, has been used to characterize the structural, electronic, and magnetic properties of the iron sulfur centers in respiratory enzymes. The enzymes studied were those associated with electron transport in mammalian mitochondria, with comparative studies of similar enzymes and proteins in heterotropic bacteria. The results …
Characterization Of The Protein And Glycoprotein Components From Antigenically Distinct Strains Of Equine Infectious Anemia Virus., Olivia Salinovich
Characterization Of The Protein And Glycoprotein Components From Antigenically Distinct Strains Of Equine Infectious Anemia Virus., Olivia Salinovich
LSU Historical Dissertations and Theses
Four isolates of equine infectious anemia virus (EIAV) recovered weeks apart from a single experimentally infected Shetland pony (Orrego, 1983) were examined in both antigenic and structural analyses to investigate variation occurring during persistent infection. These four isolates were shown to be antigenically distinct in both serum neutralization assays and in immunoblot analysis with either a polyclonal equine reference antiserum or a panel of virus-specific monoclonal antibodies. Two-dimensional mapping of tryptic peptides of viral components from these isolates revealed that both gp90 and gp45 undergo structural variation during virus replication in a single animal, but that no such structural variation …
Rearrangements Of Alpha-Halosilanes And Conformational Analysis Of Silanes., Rayomand Jal Unwalla
Rearrangements Of Alpha-Halosilanes And Conformational Analysis Of Silanes., Rayomand Jal Unwalla
LSU Historical Dissertations and Theses
A number of (alpha)-halosilanes, some which are chiral at carbon, have been prepared. Lewis acid-catalyzed rearrangements and thermal rearrangements were performed on ((alpha)-chloroethyl)diphenylmethylsilane. Both the rearrangements proceed cleanly; the major product is formed by the migration of the phenyl group from silicon to carbon. The rearranged product mixture was subjected to a Kumada-type oxidation in which the silicon-carbon is cleaved stereospecifically. Thus the principle has been established that a clean rearrangement can be carried out in a manner which will allow determination of the stereochemistry at the carbon center. Preliminary kinetic studies of the thermolysis of ((alpha)-chlorobenzyl)dimethylphenylsilanes containing p-substituents in …
Models For The Study Of Intramolecular Interactions: Preparation, Structure And Reactivity Of 2-(2'-Acyloxyphenylethynyl)Benzoic Acids., Michael Allen Oliver
Models For The Study Of Intramolecular Interactions: Preparation, Structure And Reactivity Of 2-(2'-Acyloxyphenylethynyl)Benzoic Acids., Michael Allen Oliver
LSU Historical Dissertations and Theses
The hypothesis concerning orientational effects of carboxylate in general-base catalysis is discussed, and the first models that allow proton transfer to the syn lone-pair of the carboxylate during intramolecular general-base catalysis are designed, prepared, and tested. These models use a carbon backbone of two aryl groups linked by a two carbon bridge. The syntheses of 2-(2-hydroxyphenylethynyl)benzoic acid (24) and derivatives used in these studies are described. These derivatives were also needed to evaluate the ethynyl group as the bridge linking the aryls and to aid in the design of more complex models. The hydrolysis of the dichloroacetate ester (26) is …
Photophysics And Photochemical Studies Of Polypyridine Ruthenium (Ii) Complexes., Mario Alberto Ollino
Photophysics And Photochemical Studies Of Polypyridine Ruthenium (Ii) Complexes., Mario Alberto Ollino
LSU Historical Dissertations and Theses
Stern-Volmer plots for the quenching of luminescence and for the photosubstitution reaction of tris-bipyridylruthenium(II) at 298 K were obtained. The two Stern-Volmer plots were found to be similar; this result is different from that of a previous report, but it agrees well with a general model postulated to represent the photophysical processes of the excited states of polypyridine ruthenium(II) complexes. The temperature dependence of the emission intensities and of the lifetimes of tris-bipyridylruthenium(II), cis-ibspyridyl bis-2,2'bipyridylruthenium(II), and 4,5-diazafluorenyl-bis-2,2'bipyridylruthenium(II) were reinvestigated in order to evaluate the difference in energy between the triplet metal to ligand charge transfer and ligand field excited states. …
Synthesis Of Poly(Vinylcatechols)., Saad Moulay
Synthesis Of Poly(Vinylcatechols)., Saad Moulay
LSU Historical Dissertations and Theses
5-Vinyl-1,3-benzodioxole, 28, 3,4-dimethoxystyrene, 29, 2,3-dimethoxystyrene, 30, 6-vinyl-1,4-benzodioxane, 31, and 4-vinyl-1,3-benzodioxole, 32 were synthesized and evaluated as poly(vinylcatechol) precursors. Four methods for preparing these monomers were explored. Dehydration of (alpha)-phenethyl alcohols was the best general procedure. Molecular weights as high as 95,000 in the case of poly(2,3-dimethoxystyrene) were achieved in the presence of free radical initiators. The kinetics of free radical polymerization of 2,3-dimethoxystyrene, 30, was studied dilatometrically and the overall rate of the reaction was found to be R(,p) + 2.53 x 10('-2) mol/L min. Radical copolymerizations of monomers 30 and 31 with styrene and methyl methacrylate were examined. The …