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Theses/Dissertations

Chemistry

2005

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Articles 121 - 134 of 134

Full-Text Articles in Physical Sciences and Mathematics

Hydrophobic Guar Gum Derivatives Prepared By Controlled Grafting Processes For Hydraulic Facturing Applications, Ahmad Bahamdan Jan 2005

Hydrophobic Guar Gum Derivatives Prepared By Controlled Grafting Processes For Hydraulic Facturing Applications, Ahmad Bahamdan

LSU Doctoral Dissertations

The synthesis of new water soluble guar gum derivatives is described. Introduction of polyalkoxyalkyleneamide grafts to guar gum or hydroxyopropyl guar was achieved in a three step process: carboxymethylation with sodium chloroacetate, esterification with dimethyl sulfate and amidation with a series of polyalkoxyalkylene-amines. The process steps were followed using infrared spectroscopy; the grafted guar derivatives were characterized using FT-IR and 1H NMR. A series of hydroxypropyl guar derivatives with degrees of carboxymethylations ranging from 0.15-0.25 were modified with polyalkoxyalkyleneamines with molecular weights ranging from 300-3000. The ratio of oxypropylene to oxoethylene units in the polyalkoxyalkyleneamines was varied from 9/1 …

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Synthesis Of Symmetric And Asymmetric Water-Soluble Porphyrin Derivatives, Caroline Owendi Ongayi Jan 2005

Synthesis Of Symmetric And Asymmetric Water-Soluble Porphyrin Derivatives, Caroline Owendi Ongayi

LSU Doctoral Dissertations

Novel symmetric and asymmetric water-soluble tetrabenzoporphyrin are synthesized in relatively good yields. These compounds are synthesized by the condensation of butanopyrrole with several aldehydes that contain masked water solubilizing groups followed by metal insertion, oxidation and demetallation and deprotection of the masked solubilizing groups. The biological evaluation (in vitro and in vivo) studies are described in addition to the photophysical evaluations of the corresponding compounds. A novel versatile route to the syntheses of novel free-bases and metallo-benzoylbiliverdin is discussed. The treatment of metal free-dodecasubstituted porphyrin with sodium nitrite and trifluoroacetic acid at room temperature in the presence of oxygen affords …

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Naturally-Derived Porphyrin And Chlorin Photosensitizers For Photodynamic Therapy, Jodie Angela Hargus Jan 2005

Naturally-Derived Porphyrin And Chlorin Photosensitizers For Photodynamic Therapy, Jodie Angela Hargus

LSU Master's Theses

In oncologic applications of photodynamic therapy (PDT), the discriminating localization of porphyrin-type compounds in solid tumors is exploited for the selective ablation of neoplastic tissue with minimal destruction and irritation to normal tissue. PDT is a locoregional, binary cancer therapy in which a photosensitizer—light-activated drug—absorbs light of an appropriate wavelength and excites to the singlet state. This photosensitizer in the excited singlet state can undergo an internal transition to the excited triplet state, a relatively long-lived and high-energy species that transfers its excess energy to molecular oxygen. Molecular oxygen subsequently excites from the stable triplet state to the highly reactive …

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Enantioselective Syntheses And Chemical Investigations Of Plant-Derived Bioactive Volatile Compounds, Anne Marie Sauer Jan 2005

Enantioselective Syntheses And Chemical Investigations Of Plant-Derived Bioactive Volatile Compounds, Anne Marie Sauer

LSU Doctoral Dissertations

Research, inspired by nature, provides ample opportunity for discovery, ingenuity, and creative endeavor. For these reasons, the work and accomplishments presented herein focus on the total syntheses and related investigations of a variety of natural product derivatives, specifically (+)-nootkatone and jasmone. While the former consists of several independent projects: (a) an enantioselective synthetic route to (+)-nootkatone and derivatives, (b) examination of the valencane ring system, (c) determination of the absolute configuration of (+)-nootkatone, and (d) rearrangements of various sesquiterpenoid derivatives; the latter focuses on the construction ofƒndelta, epsilon-unsaturated carbonyl compounds, hetero Pauson-Khand substrates, via [3,3]-sigmatropic rearrangements.

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Separation And In Situ Catalytic Testing Of A Dirhodium Tetraphosphine Catalyst, Bobby Lloyd Barker Jan 2005

Separation And In Situ Catalytic Testing Of A Dirhodium Tetraphosphine Catalyst, Bobby Lloyd Barker

LSU Doctoral Dissertations

Attempts to study the asymmetric hydroformylation abilities of [rac-Rh2(nbd)2(et,ph-P4)](BF4)2 were made through the separation of the enantiomers of et,ph-P4 using a chiral HPLC column. Efforts were also made to optimize the NiCl2 separation chemistry for the methyl analogue of et,ph-P4 for use in asymmetric hydroformylation. A study of hydroformylation of olefins using [rac-Rh2(nbd)2(et,ph-P4)](BF4)2 in ionic liquids was also performed, leading directly to the important (and unexpected) effect of increased hydrogen pressure on [rac-Rh2(nbd)2(et,ph-P4)](BF4)2 in the acetone/water system to …

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Synthesis, Characterization And Application Of Polymeric Surfactants In Micellar Electrokinetic Chromatography: Use Of Ionic Liquids As Modifiers, Simon M. Mwongela Jan 2005

Synthesis, Characterization And Application Of Polymeric Surfactants In Micellar Electrokinetic Chromatography: Use Of Ionic Liquids As Modifiers, Simon M. Mwongela

LSU Doctoral Dissertations

The goal of the research presented in this dissertation is to synthesize, characterize, and apply a novel chiral amino acid-based surfactant and achiral sulfate-based surfactants for the effective separations of chiral and achiral compounds in micellar electrokinetic chromatography (MEKC). The first part of this research involves novel synthesis, characterization, and application of polysodium oleyl-L-leucyl-valinate (poly-L-SOLV) for the separation of chiral compounds in MEKC. Surface tensiometry, proton nuclear magnetic resonance, infrared spectroscopy, densitometry and analytical ultracentrifugation were used as the characterization techniques. Optimal MEKC separating conditions were established by varying surfactant concentration, buffer concentration and pH, applied voltage, and capillary temperature. …

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The Stereoselective Synthesis Of The Butyrolactone-Bridged [8-5-5] Tricyclic Ring Systems Of (+/-)-Asteriscanolide Via The Titanium-Mediated Hetero-Pauson-Khand Reaction, Mohamed G. Sherriff Jan 2005

The Stereoselective Synthesis Of The Butyrolactone-Bridged [8-5-5] Tricyclic Ring Systems Of (+/-)-Asteriscanolide Via The Titanium-Mediated Hetero-Pauson-Khand Reaction, Mohamed G. Sherriff

LSU Doctoral Dissertations

The stereoselective construction of the tricyclic ring system of asteriscanolide from cyclooctadiene has been achieved. The synthesis involves two main steps; the synthesis of the aldehyde precursor(5)and the titanium-mediated cabocyclization of 5 to make the three rings of 43 stereoselectively.

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Bismuth Triflate Catalyzed Friedel-Crafts Acylations Of Sydnones, Jennifer Ann Fisher Jan 2005

Bismuth Triflate Catalyzed Friedel-Crafts Acylations Of Sydnones, Jennifer Ann Fisher

Browse all Theses and Dissertations

In the present work, suitably functionalized arylsydnones were used to synthesize a variety of 4-acylsydnones and diacyl sydnones, both as potential precursors to novel sydnoquinolines.The approach to the diacyl species is based on the discovery that activated sydnonesbrominate in both the 4 position of the sydnone ring and on the phenyl ring. Thus, it seemed likely that Friedel-Crafts reactions on an activated sydnone would give diacylated species for McMurray coupling to sydnoquinolines. Friedel-Crafts acylations on the 4 position of the sydnone ring have been achieved in high yields using 4 equivalents of various alkyl anhydrides, 25 mol % of bismuth …

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Electronic To Vibrational Energy Transfer From Cl* (3 2P1/2) To N2O(Ν1): Failure Of A Simple Kinetic Mechanism, Brian Brumfield Jan 2005

Electronic To Vibrational Energy Transfer From Cl* (3 2P1/2) To N2O(Ν1): Failure Of A Simple Kinetic Mechanism, Brian Brumfield

Browse all Theses and Dissertations

Experimental kinetic studies were carried out examining the electronic to vibrational (E-V) energy transfer from spin-orbit excited Cl*(3 2P1/2 , 882 cm-1) to N2O(ν1) (symmetric stretch 1285 cm-1). All studies were carried out in the gas phase at room temperature (298 ± 2 K). Cl* was generated by pulsed laser photolysis of ICl at 532 nm in the presence of various mixtures of N2O, ICl,Ar, and SO2. Time-resolved IR signals of N2O(ν1) fluorescence at 7.8 μm were analyzed to obtain rate coefficients …

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The Importance Of Size And Shape In Imprinted Polymers, Jason Campbell Jan 2005

The Importance Of Size And Shape In Imprinted Polymers, Jason Campbell

LSU Master's Theses

The existence of shape selectivity in non-covalent molecularly imprinted polymers has been proven using molecular probes. A series of amines varying with different structural motifs and secondary amines with different sized side chains were imprinted, and binding evaluated by HPLC for each amine on polymers imprinted with similar amines. Trends in the binding relationships revealed two major contributions of cavity structure on selectivity afforded by molecularly imprinted polymers (MIPs). First, sterics play a dominant role in cases where a molecules structure is too big too fit into an imprinted site formed from a smaller template molecule. Second, molecular structures that …

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Capillary And Microchip Gel Electrophoresis Using Multiplexed Fluorescence Detection With Both Time-Resolved And Spectral-Discrimination Capabilities: Applications In Dna Sequencing Using Near-Infrared Fluorescence, Li Zhu Jan 2005

Capillary And Microchip Gel Electrophoresis Using Multiplexed Fluorescence Detection With Both Time-Resolved And Spectral-Discrimination Capabilities: Applications In Dna Sequencing Using Near-Infrared Fluorescence, Li Zhu

LSU Doctoral Dissertations

Increasing the information content obtainable from a single assay and system miniaturization has continued to be important research areas in analytical chemistry. The research presented in this dissertation involves the development of a two-color, time-resolved fluorescence microscope for the acquisition of both steady-state and time-resolved data during capillary and microchip electrophoresis. The utility of this hybrid fluorescence detector has been demonstrated by applying it to DNA sequencing applications. Coupling color discrimination with time-resolved fluorescence offers increased multiplexing capabilities because the lifetime data adds another layer of information. An optical fiber-based fluorescence microscope was constructed, which utilized fluorescence in near-IR region, …

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Molecular Recognition And Its Underlying Mechanisms In Molecularly Imprinted Polymers, Ryan Simon Jan 2005

Molecular Recognition And Its Underlying Mechanisms In Molecularly Imprinted Polymers, Ryan Simon

LSU Doctoral Dissertations

Molecular recognition in molecularly imprinting polymers (MIPs) is governed by two mechanisms: pre-organization of functional groups and shape specificity of the binding site. While pre-organization of functional groups has been studied extensively, shape specificity of the binding site has not been rigorously explored. The goal of this research is to determine the influence of shape specificity on molecular recognition in MIPs (Chapter 2). Once shape selectivity was proven to play a vital role in molecular recognition, it was important to determine if pre-organization of functional groups or shape specificity was the dominating factor in determining molecular recognition in the binding …

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Heavy Metal Complexes Of Mixed S,N Donor Ligands: X-Ray Crystallography And Solution-State 1h Nmr, Wei Lai Jan 2005

Heavy Metal Complexes Of Mixed S,N Donor Ligands: X-Ray Crystallography And Solution-State 1h Nmr, Wei Lai

Dissertations, Theses, and Masters Projects

No abstract provided.

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Bi(Iii) Initiated Cyclization Reactions And Iodonium Fragmentation Kinetics, Yajing Lian Jan 2005

Bi(Iii) Initiated Cyclization Reactions And Iodonium Fragmentation Kinetics, Yajing Lian

Dissertations, Theses, and Masters Projects

No abstract provided.

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