Chemistry Commons^™

Evaluation Of Single Electron Transfer Reduction Products Of 3-Oxoindoles As Antibacterial Agents, Debasish Bandyopadhyay, Irani Biswas, Subrata Laskar, Bidyut Basak

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

Objective: The objective of the present study is to assess the antibacterial properties of six indole derivatives viz, 3-(Naphth-1-y - methyl) –indole (II), 3-(1-Naphthylcarbonyl – indole (III), 3,3' –diformyl-2,2' –bis indole (IV), 1,4- (3,3' –di indolyl) – 1,4-dioxobutane (V), 3-benzoyl indole (VI) and 1,1 – bis – (3-indolyl)- ethane (VII) synthesized by single electron transfer reduction of 3-formylindole (I) against two Gram +ve and two Gram –ve bacteria which usually cause human infections.

Methods: Synthesis of 3-formyl indole from which the indole derivatives were prepared were further characterized by IR and NMR analysis. The six synthesized compounds were screened for …

Molecular Products From The Thermal Degradation Of Selected Tobacco Components: Lignin, Tyrosine, Glutamic Acid, And Modeling Of Lignin Pyrolysis Using Chemkin Combustion Suite, Joshua Kiprotich Kibet

LSU Doctoral Dissertations

This study explores the thermal decomposition behavior of selected tobacco components: lignin, tyrosine, and glutamic acid using the system for thermal diagnostic studies (STDS) in an in-line gas chromatography-mass spectrometer analytical technique. The pyrolysis conditions employed in this study were a flowing atmosphere of nitrogen and 4% O2 in nitrogen at a residence time of 0.2 seconds for a total pyrolysis time of 3 minutes. The results identified common relationships between the two modes of reaction atmospheres, as well as some differences. While some products were favored by an inert regime, some were favored under an oxidative regime. Oxidative pyrolysis …

Advancing The Field Of Polypeptoids Through The Synthesis Of Novel Architectures And Thermoresponsive Polymers, Samuel Henry Lahasky

LSU Doctoral Dissertations

Peptidomimetic polymers are an emerging class of polymers that are structurally related to polypeptides. Due to their structural similarities, these polymers can be used to study some of the physical aspects of polypeptides (for example, protein folding). They are also increasingly being used in the fields of biology and drug-delivery. Some members of peptidomimetic polymers include polyacrylamides, polyoxazolines and polypeptoids. Polymer synthesis and characterization has been performed for both polyacrylamides and polyoxazolines, with research dating back to the 1950s and 1980s respectively. Research in the field of polypeptoids has not been as extensive; however, emerging synthetic strategies are allowing for …

Amplifying Conjugated Polymers For Fluorescent Chemosensing, Deepa Pangeni

LSU Doctoral Dissertations

Chemo- and biosensors based on fluorescent conjugated polymers benefit from greater detection sensitivity due to amplification of the electronic perturbations produced by analyte binding. This amplification stems from the exciton-transporting properties of conjugated polymers. In the conventional sensor design paradigm, excitons migrate from the bulk of the polymer to the analyte binding sites which can be either fluorescence quenching sites (turn-off sensors) or lower energy fluorophores (turn-on sensors). In this dissertation, we proposed an alternative design paradigm when analyte binding creates a higher energy gap site in the polymer backbone. In the case of isolated polymer chains in dilute solution, …

Energy Of The Quasi-Free Electron In Repulsive Atomic And Molecular Fluids, Yevgeniy Lushtak

Dissertations, Theses, and Capstone Projects

The ability to predict accurately the energy V₀(ρ) of the quasi-free electron along the entire density (ρ) range of a supercritical fluid has applications in determining the ideal thermodynamic conditions for chemical reactions involving charged species. The previously established field ionization method of extracting V₀(ρ) from the fluid density dependent shift Δ(ρ) in the ionization energy of a dopant molecule has led to the discovery of a novel effect on V₀(ρ) occurring near the critical isotherm of the fluid. Unfortunately this method has limitations in determining V₀(ρ) in fluids with low critical …

Mass Spectrometric Analysis Of Oxidized Eicosapentaenoic Acid Sodium Salt, Kelsey D. Jordan, Rita K. Upmacis

Faculty Papers and Publications

Eicosapentaenoic acid (EPA) is an omega-3 polyunsaturated fatty acid (PUFA) with 20 carbon atoms and 5 carbon-carbon double bonds. Mammalian cells cannot synthesize long chain PUFAs such as EPA de novo, and, thus, the most effective way to enrich cells in EPA is by dietary intake of fish oils. EPA supplementation causes an increase in its concentration in plasma lipids and in cell membrane phospholipids. Many beneficial effects of EPA supplementation have been noted, including (1) the potential to sensitize cancerous tumors towards chemotherapy, (2) the promotion of cardiovascular health, and (3) the alleviation of some mental disorders, but results …

Effects Of Micro-Solvation On Room Temperature Ionic Liquids, Joseph Wellington Golden

Honors Theses

Room temperature ionic liquids (RTILs) have received much attention lately. These compounds are made completely of ions and are liquid at or near room temperature. These liquid salts have a number of unique properties that make them an interesting system to study. These properties include almost zero vapor pressure, thermal stability, large liquidus range, etc. Due to these properties and others, ionic liquids (ILs) have attracted much attention in the emerging field of green chemistry as potentially new solvents for many of the hazardous and volatile solvents currently in use. Moreover, the complex interactions of the anion and cation systems …

Programmable Polymers Preparation Optimization And Applications On Solute Templates, Yinyan He

Theses and Dissertations

Programmable polymer is a type of stimuli-responsive polymer which can keep their induced properties after removal of the stimulu, as well as programmable polymers maintain the general properties as stimuli-responsive polymers, such as recognize and respond to the stimulus. The previous reported solvent Caryl-Nimide bonds based programmable polymers (SPP-1) can freely rotate and change the carboxylic acid recognition group orientation in response to templates. Solvent templates were used in the SPP-1. One potential application for SPPs is using their recognition and memory properties for the identification and separation of mixture solutions of various analytes. In my first project, I wanted …

Functional Block Copolymers For Applications In Advanced Materials, Energy Storage, And Lithography, Christopher George Hardy

Theses and Dissertations

Block copolymers spontaneously self-assembly into a wide variety of ordered nanostructures on the length scale of 5 - 100 nm due to the thermodynamic immiscibility between the covalently linked, chemically distinct polymer chains. Incorporating desirable functional groups into block copolymer systems can lead to confinement of the functional group to a specific domain upon microphase separation of the block copolymer. The resulting materials display desirable characteristics of the functional group in a well-ordered nanostructure. Such systems have been utilized in a wide variety of applications including catalysis, ceramic materials, and membranes. This dissertation is focused on the synthesis, characterization, self-assembly …

Development And Figures Of Merit Of Microextraction And Ultra-Performance Liquid Chromatography For Forensic Characterization Of Dye Profiles On Trace Acrylic, Nylon, Polyester, And Cotton Textile Fibers, Scott James Hoy

Theses and Dissertations

Methodology for the microextraction of basic dyes on acrylic, acid dyes on nylon, disperse dyes on polyester, and reactive dyes, direct dyes, and indigo on cotton textile fibers is reported. Although these processes are destructive to the fiber evidence, the ability to analyze dye extracts from sub-millimeter fiber lengths of single fibers, coupled with detection limits in the hundred picogram range by ultra-performance liquid chromatography (UPLC) with both diode array detection (DAD) and tandem mass spectrometry (MS-MS) makes routine forensic characterization feasible.

Microextraction, followed by UPLC, can often distinguish similar fibers containing different, but similar, dyes with the combination of …

Design And Synthesis Of Polymer-Based Advanced Nanomaterials Using Raft Polymerization And Click Reaction, Junting Li

Theses and Dissertations

This research focuses on exploring new synthetic approaches to prepare polymer-based advanced nanomaterials using highly efficient chemical tools, such as reversible addition-fragmentation chain transfer (RAFT) polymerization and click reactions.

In the first project, novel synthetic routes to produce fullerene-based polymers were designed. First, mono-alkynyl functionalized fullerene was prepared starting with pristine fullerene (C₆₀). Methyl methacrylate and 6-azido hexyl methacrylate were then randomly copolymerized via RAFT polymerization with well-controlled molecular weights and copolymer compositions. Finally, the two moieties were covalently assembled into a series of well-defined side-chain fullerene polymers (SFP's) via the copper-catalyzed click reaction. The TGA and UV-vis …

Polybenzimidazole Membranes With Enhanced Mechanical Properties For Extended Lifetime Electrochemical Applications, Max Molleo

Theses and Dissertations

After approximately 20 years of development, polybenzimidazole (PBI) chemistries and the concomitant manufacturing processes have evolved into commercially produced membrane electrode assemblies (MEAs). Commerical PBI MEAs can operate reliably for over two years at elevated temperatures of 120-180°C due to the physical and chemical robustness of PBI membranes. Recently, the Department of Energy has issued a target of 40,000-80,000 hours for stationary (i.e. combined heat and power, back-up power) polymer electrolyte membrane / proton exchange membrane (PEM) fuel cells. It is known through observation that over time, PBI membranes at 180°C creep in a direction perpendicular to compressive forces, thus …

Iridium-Ruthenium/Osmium-Gold Cluster Complexes: Unique Structures And Properties, Qiang Zhang

Theses and Dissertations

Chapter Two

The first Ir-Ru cluster complex was synthesized was the electron-rich, anionic, planar cluster complex [PPN][IrRu6(CO)23], 2.5, (PPN=Bis(triphenylphophoranylidene)-ammonium) which obtained from the reaction of [PPN][IrRu3(CO)13] with one equivalent ruthenium carbonyl (Ru3(CO)12) at 66 oC (THF reflux) for 12h. Compound 2.5 could also be synthesized by using the mono-Iridium compound [PPN][Ir(CO)4] reacts with two equivalent of ruthenium carbonyl. In compound 2.5, all seven metal atoms lie in a plane (max deviation = 0.043(1) Å) with the iridium atom in the center circumscribed by a hexagonal ring of six ruthenium atoms. The anion 2.5 contains 104 valence electrons while both the …

Silylation-Based Kinetic Resolution Of Α-Hydroxy Carbonyl Compounds And Synthesis Of Chiral Isothiourea Catalysts, Yan Zhang

Theses and Dissertations

The thesis describes the silylation-based kinetic resolution for α-hydroxy carbonyl compounds catalyzed by isothiourea catalyst as well as our effort to make novel chiral isothiourea catalyst.

In Chapter 1, general background will be introduced, including chirality, general methods to obtain enantiopure compounds and kinetic resolution. In Chapter 2, the mechanism of the chiral recognition was discussed and a novel isothiourea catalyst was design to investigate the mechanism. The synthesis of the new catalyst was also described in this chapter.

In Chapter 3, the silylation-based kinetic resolution for α-hydroxy carbonyl compounds will be discussed. Since silylation-based kinetic resolution have already been …

Plant Virus Based Materials For Cell Alignment And Differentiation, Elizabeth Balizan

Theses and Dissertations

This research focused on developing and using plant virus based scaffolds to understand substrate control over cell alignment and differentiation. The first part of this work centered on development of virus based patterns that were then used to align and elongate aortic smooth muscle cells (SMCs). Virus patterns were generated in capillary tubes via a simple drying method. Three experimental parameters were used to control pattern formation: (1) protein concentration, (2) salt concentration, and (3) hydrophobicity of the pre-deposition surface. By controlling these parameters several aspects of the final virus patterns were controlled. First, virus orientation was controlled. Patterns were …

A Silylation Based Kinetic Resolution Of Secondary Alcohols And The Synthesis And Structural Characterization Of Pyridyl-Oxazolidine Compounds, Cody Ian Sheppard

Theses and Dissertations

Described herein is the first enantioselective silylation based kinetic resolution of monofunctional secondary alcohols to achieve useful levels of enantioselectivity. Using commercially available reagents, the reaction conditions were optimized and found to successfully resolve several secondary alcohols with high enantioselectivity. It was discovered that the nucleophilic isothiourea compound (-)-tetramisole, with Ph3SiCl as the silyl source, gave superior results to other nucleophilic catalysts and was capable of performing the kinetic resolution in as little as 45 minutes using mild reaction conditions. The structural and electronic characteristics of successful and less successful substrates are also discussed.

Chapter three discusses mechanistic investigations and …

The Scope Of The Bis-Urea Macrocycle Assembly Motif, Michael F. Geer

Theses and Dissertations

From the formation of rock candy crystals, to the functionality of DNA in the cell, to the cosmic dust throughout the universe, supramolecular chemistry has a great impact and importance in the world around us. In this thesis, we explore the supramolecular interactions and self-assembly of bis¬-urea macrocyclic systems and investigate how their structure and assembly influences bulk properties and functionality. Specifically, in chapter one, we review the factors that guide, limit, and define supramolecular structures from the atomic to the centimeter scale.

In chapter two, we investigate the incorporation of benzophenone, a well known triplet sensitizer, within a bis-urea …

Single Crystal To Single Crystal Polymerization Of A Columnar Assembled Diacetylene Macrocycle, Weiwei Xu

Theses and Dissertations

Organic tubular materials have attracted lots of attentions for their potential applications as nanoscale fluidic transport systems, specific ion sensors, molecular sieves and confined molecular reaction containers. While conjugated polymers, due to delocalized Pi electrons, exhibit interesting solar cells and sensors applications. In this thesis, we developed a conjugated polymer which combines the attributes of conjugated polymers with tubular materials, which should have great potential to work as a sensing material.

We reproduced and scaled-up the synthesis of a polymerizable macrocycle 1 that contains two rigidly separated diacetylene units. We found that, through hydrogen bonding, 1 can assemble into columnar …

Investigations Of The Non-Covalent Ch-Π Interactions Using Molecular Torsional Balances, Chen Zhao

Theses and Dissertations

Several bicycle N-arylimide based molecular balances were designed to study aliphatic CH-pi interactions and aromatic CH-pi interactions (edge-to-face arene-arene interactions). In each case, the geometries of the interactions were characterized in the solid-state via X-ray analysis, and the strengths of interactions were characterized in solution by their folded/unfolded ratios, as measured by integration of their 1H NMR spectra.

The balances are very sensitive to variations in the strengths of weak non-covalent interactions. Several different aspects of the CH-pi interactions were studied, such as sterics, conformational entropy, cooperativity, deuterium isotope effect, substitution effects, and solvent effects. It showed that due to …

Characterizing Interactions Between Chromophores In Synthetic And Natural Macromolecular Films Via Maldi-Tof, Ibf And Dielectric Analyzer, Parul Jain

USF Tampa Graduate Theses and Dissertations

With the emergence of Matrix Assisted Laser Desorption/Ionization-Time-of-flight as a tool for diagnosis of diseases via proteomics, there is an increasing need for greater sensitivity. Analysis of peptides by MALDI-TOF-MS is affected by sample formulation and spotting onto a MALDI target. This dissertation investigates a novel MALDI sample preparation technique, Induction Based Fluidics (IBF), for depositing precise volumes (pL to nL) of samples onto the target. We have seen that while using IBF, the induced electric field accompanying deposition enhances matrix crystallization yielding smaller crystals with more homogeneity, as compared to conventional manual micropipette (MP) depositions. An investigation of the …

No Longer A Complex, Not Yet A Molecule: A Challenging Case Of Nitrosyl O-Hydroxide, Hoon, Majher I. Sarker, Tasnuva Shahrin, Mark G. Steinmetz, Qadir K. Timerghazin

Chemistry Faculty Research and Publications

N-(9-Oxothioxanthenyl)benzothiophene carboxamides bearing leaving groups (LG⁻ = Cl⁻, PhS⁻, HS⁻, PhCH₂S⁻) at the C-3 position of the benzothiophene ring system photochemically cyclize with nearly quantitative release of the leaving group, LG⁻. The LG⁻ photoexpulsions can be conducted with 390 nm light or with a sunlamp. Solubility in 75% aqueous CH₃CN is achieved by introducing a carboxylate group at the C-6 position of the benzothiophene ring. The carboxylate and methyl ester derivatives regiospecifically cyclize at the more hindered C-1 position of the thioxanthone ring. …

Photochemical Electrocyclic Ring Closure And Leaving Group Expulsion From N-(9-Oxothioxanthenyl)Benzothiophene Carboxamides, Majher I. Sarker, Tasnuva Shahrin, Mark G. Steinmetz, Qadir K. Timerghazin

Chemistry Faculty Research and Publications

N-(9-Oxothioxanthenyl)benzothiophene carboxamides bearing leaving groups (LG⁻ = Cl⁻, PhS⁻, HS⁻, PhCH₂S⁻) at the C-3 position of the benzothiophene ring system photochemically cyclize with nearly quantitative release of the leaving group, LG⁻. The LG⁻ photoexpulsions can be conducted with 390 nm light or with a sunlamp. Solubility in 75% aqueous CH₃CN is achieved by introducing a carboxylate group at the C-6 position of the benzothiophene ring. The carboxylate and methyl ester derivatives regiospecifically cyclize at the more hindered C-1 position of the thioxanthone ring. …

Global Permutationally Invariant Potential Energy Surface For Ozone Forming Reaction, Mehdi Ayouz, Dmitri Babikov

Chemistry Faculty Research and Publications

We constructed new global potential energy surface for O + O₂ → O₃ reaction. It is based on high level electronic structure theory calculations and employs fitting by permutationally invariant polynomial functions. This method of surface construction takes full advantage of permutation symmetry of three O nuclei and allows reducing dramatically the number of ab initio data points needed for accurate surface representation. New potential energy surface offers dramatic improvement over older surface of ozone in terms of dissociation energy and behavior along the minimum energy path. It can be used to refine the existing theories of ozone …

Frozen Rotor Approximation In The Mixed Quantum/Classical Theory For Collisional Energy Transfer: Application To Ozone Stabilization, Alexander Teplukhin, Mikhail V. Ivanov, Dmitri Babikov

Chemistry Faculty Research and Publications

A frozen-rotor approximation is formulated for the mixed quantum/classical theory of collisional energy transfer and ro-vibrational energy flow [M. Ivanov and D. Babikov, J. Chem. Phys.134, 144107 (Year: 2011)]. Numerical tests are conducted to assess its efficiency and accuracy, compared to the original version of the method, where rotation of the molecule in space is treated explicitly and adiabatically. New approach is considerably faster and helps blocking the artificial ro-vibrational transitions at the pre- and post-collisional stages of the process. Although molecular orientation in space is fixed, the energy exchange between rotational, vibrational, and translational digresses of freedom still occurs, …

Equivalence Of The Ehrenfest Theorem And The Fluid-Rotor Model For Mixed Quantum/Classical Theory Of Collisional Energy Transfer, Alexander Semenov, Dmitri Babikov

Chemistry Faculty Research and Publications

The theory of two seemingly different quantum/classical approaches to collisional energy transfer and ro-vibrational energy flow is reviewed: a heuristic fluid-rotor method, introduced earlier to treat recombination reactions[M. Ivanov and D. Babikov, J. Chem. Phys.134, 144107 (Year: 2011)10.1063/1.3576103], and a more rigorous method based on the Ehrenfest theorem. It is shown analytically that for the case of a diatomic molecule + quencher these two methods are entirely equivalent. Notably, they both make use of the average moment of inertia computed as inverse of average of inverse of the distributed moment of inertia. Despite this equivalence, each of the two formulations …

Identification Of A Histidine Metal Ligand In The Arge-Encoded N-Acetyl-L-Ornithine Deacetylase From Escherichia Coli, Wade C. Mcgregor, Danuta Gillner, Sabina I. Swierczek, Dali Liu, Richard C. Holz

Chemistry Faculty Research and Publications

The H355A, H355K, H80A, and H80K mutant enzymes of the argE-encoded N-acetyl-L-ornithine deacetylase (ArgE) from Escherichia coli were prepared, however, only the H355A enzyme was found to be soluble. Kinetic analysis of the Co(II)-loaded H355A exhibited activity levels that were 380-fold less than Co(II)-loaded WT ArgE. Electronic absorption spectra of Co(II)-loaded H355A-ArgE indicate that the bound Co(II) ion resides in a distorted, five-coordinate environment and Isothermal Titration Calorimetry (ITC) data for Zn(II) binding to the H355A enzyme provided a dissociation constant (K_d) of 39 μM. A three-dimensional homology model of ArgE was generated using the …

Molecular Docking And Nmr Binding Studies To Identify Novel Inhibitors Of Human Phosphomevalonate Kinase, Pornthip Boonsri, Terrence S. Neumann, Andrew Lawrence Olson, Sheng Cai, Timothy J. Herdendorf, Henry M. Miziorko, Supa Hannongbua, Daniel S. Sem

Chemistry Faculty Research and Publications

Phosphomevalonate kinase (PMK) phosphorylates mevalonate-5-phosphate (M5P) in the mevalonate pathway, which is the sole source of isoprenoids and steroids in humans. We have identified new PMK inhibitors with virtual screening, using autodock. Promising hits were verified and their affinity measured using NMR-based ¹H–¹⁵N heteronuclear single quantum coherence (HSQC) chemical shift perturbation and fluorescence titrations. Chemical shift changes were monitored, plotted, and fitted to obtain dissociation constants (K_d). Tight binding compounds with K_d’s ranging from 6–60 μM were identified. These compounds tended to have significant polarity and negative charge, similar to the natural …

Mixed Quantum/Classical Theory Of Rotationally And Vibrationally Inelastic Scattering In Space-Fixed And Body-Fixed Reference Frames, Alexander Semenov, Dmitri Babikov

Chemistry Faculty Research and Publications

We formulated the mixed quantum/classical theory for rotationally and vibrationally inelastic scattering process in the diatomic molecule + atom system. Two versions of theory are presented, first in the space-fixed and second in the body-fixed reference frame. First version is easy to derive and the resultant equations of motion are transparent, but the state-to-state transition matrix is complex-valued and dense. Such calculations may be computationally demanding for heavier molecules and/or higher temperatures, when the number of accessible channels becomes large. In contrast, the second version of theory requires some tedious derivations and the final equations of motion are rather complicated …

Ro-Vibrational Quenching Of Co (V = 1) By He Impact In A Broad Range Of Temperatures: A Benchmark Study Using Mixed Quantum/Classical Inelastic Scattering Theory, Alexander Semenov, Mikhail V. Ivanov, Dmitri Babikov

Chemistry Faculty Research and Publications

The mixed quantum/classical approach is applied to the problem of ro-vibrational energy transfer in the inelastic collisions of CO(v = 1) with He atom, in order to predict the quenching rate coefficient in a broad range of temperatures 5 < T < 2500 K. Scattering calculations are done in two different ways: direct calculations of quenching cross sections and, alternatively, calculations of the excitation cross sections plus microscopic reversibility. In addition, a symmetrized average-velocity method of Billing is tried. Combination of these methods allows reproducing experiment in a broad range of temperatures. Excellent agreement with experiment is obtained at 400 < T < 2500 K (within 10%), good agreement in the range 100 < T < 400 K (within 25%), and semi-quantitative agreement at 40 < T < 100 K(within a factor of 2). This study provides a stringent test of the mixed quantum/classical theory, because the vibrational quantum in CO molecule is rather large and the quencher is very light (He atom). For heavier quenchers and closer to dissociation limit of the molecule, the mixed quantum/classical theory is expected to work even better.

Silica Polypeptide-Based Colloids: Physical Properties And Novel Materials, Cornelia Rosu

LSU Doctoral Dissertations

The investigation of polypeptide composite particles, PCPs, is described. The production of mesoporous and polycolloid architectures is also addressed. PCPs were prepared by both growing form and grafting to method. They consist of a core made of silica, silica-coated magnetite or silica-coated cobalt. Some of the particles were covalently labeled with fluorescein isothiocyanate. Several polypeptides were chosen for attachment on the core: poly(γ-stearyl-L-glutamate), PSLG, poly(Nε-carbobenzyloxy-L-lysine), PCBL and poly(o-benzyl-L-tyrosine), PBTY. Attachment of a well-characterized alkyne-end terminated PSLG and PCBL to an azide- functionalized particle yielded PCPs with a desired sparse coverage. A blend of techniques such as FTIR, XPS, TEM, HTEM, …