Chemistry Commons^™

Synthesis Of Chemical Models Of Hydrolase Enzymes For Intramolecular Catalysis., Cornelius Ndi Ndi

Electronic Theses and Dissertations

Most nuclease enzymes can hydrolyze phosphoester bonds (in DNA and RNA) by using metal ions cofactors that coordinate and activate water molecules in the enzymes' active sites. However, there are some hydrolase enzymes (including nucleases) that can function without the aid of metal ions. 2,6-Di(1H-imidazol-2-yl)phenol, a model compound for hydrolase enzyme, was synthesized by the reaction between ethylenediamine and dimethyl-3-carboxysalicylate, initially resulting in the formation of diimidazoline. The diimidazoline was subsequently aromatized to the diimidazole by dehydrogenation over palladium. The overall reaction yield was low; therefore, other dehydrogenation transformation reactions were tried but all failed to improve the …

Self-Assemblies Driven By The Hydrophobic Effect, Haiying Gan

University of New Orleans Theses and Dissertations

Water is a simple molecule but is an essential part of life. One key aspect of the properties of water is the hydrophobic effect, and whilst there is an appreciation of this phenomenon at the macro-scale (raindrops falling off leaves) and the micro-scale (the structure of cellular systems), a complete understanding at the molecular level still eludes science. Addressing this issue, our studies involve synthetic supramolecular compounds that assemble in water via the hydrophobic effect.

First of all, a novel water-soluble deep-cavity cavitand was synthesized. It possesses four endo methyl groups on top rim of the cavitand, eight water-solubilizing carboxylic …

Synthesis And Biological Evaluation Of Aeruginosin Based Compounds And Self-Assembly Of Glucosamine Based Compounds, Navneet Goyal

University of New Orleans Theses and Dissertations

Aeruginosins are a family of marine natural products containing mostly non-proteogenic amino acids. These compounds contain a common 2-carboxy-6-hydroxy-octaindole (Choi) rigid bicyclic structure. Many aeruginosins are inhibitors for enzymes involved in the blood coagulation cascade, such as thrombin and Factor VIIa. In order to understand the structure activity relationship (SAR) of the aeruginosins and to discover novel anticoagulants with potentially improved inhibitory and pharmacokinetic properties, in the first part of my thesis I have discussed, synthesis of a series of novel analogs of aeruginosin 298-A, in which the Choi will be replaced with L-proline and oxygenated Choi analogs, and the …

Development Of A Glycoconjugate Tool Set For The Assembly And Presentation Of Carbohydrate Ligands On Surfaces, Irene Esah Abia

Doctoral Dissertations

Carbohydrate and protein interactions are often essential in viral and bacterial infection, the immune response, cell differentiation and development, and the progression of tumor cell metastasis. Therefore, an understanding of carbohydrate–protein interactions at the molecular level would lead to a better insight into the biological process of living systems and assist in the development of therapeutic and diagnostic strategies. Our goal was to synthesize different mannose derivatives, immobilize them on nano-patterned surfaces and carry out binding studies with mannose-binding lectins in order to characterize carbohydrate–protein interactions.

Different derivatives of D-mannose (monosaccharide, (1→2)-linked disaccharide, (1→3)-linked disaccharide, and (1→2, 1→3)-linked trisaccharide) with …

Synthesis And Characterization Of Catalysts For The Selective Transformation Of Biomass-Derived Materials, Isaac Tyrone Ghampson

Electronic Theses and Dissertations

The experimental work in this thesis focuses on generating catalysts for two intermediate processes related to the thermal conversion of lignocellulosic biomass: the synthesis and characterization of mesoporous silica supported cobalt catalysts for the Fischer-Tropsch reaction, and an exploration of the reactivity of bulk and supported molybdenum-based nitride catalysts for the hydrodeoxygenation (HDO) of guaiacol, a lignin model compound. The first section of the work details the synthesis of a series of silicasupported cobalt Fischer-Tropsch catalysts with pore diameters ranging from 2-23 nm. Detailed X-ray diffraction measurements were used to determine the composition and particle diameters of the metal fraction, …

Studies Toward The Development Of A Microelectrode Array For Detection Of Dopamine Through Redox Cycling, Anupama Aggarwal

Graduate Theses and Dissertations

Redox cycling is an electrochemical technique that cycles the reversible redox species between its oxidative states repeatedly on generator and collector electrodes. Two or more individually-addressable microelectrodes located close to each other allow redox cycling to be possible. Electrochemical behavior of a biologically important molecule, dopamine is examined under redox cycling conditions. To our knowledge, this is the first report on detection of physiological concentration of dopamine in presence of up to 100 times excess ascorbate with the use of redox cycling, without the involvement of polymer coating such as Nafion®.

Microfabrication was used to produce different geometries (parallel bands …

The Design, Synthesis And Application Of A Novel Class Of N-Heterocyclic Carbene Catalysts, Abigail Lynn Hubbard

Graduate Theses and Dissertations

A copper carbenoid representative of a novel class of N-heterocyclic carbene (NHC) catalysts has been synthesized. This compound was characterized by X-ray crystallography and was found to confirm the rationale of our synthetic design: The C2-symmetric structure places four stereocenters in close proximity (<5Å) to the reactive site of the carbene via a trans-annular gearing effect. The copper carbenoid was found to catalyze the hydrosilylation of prochiral ketones with superb selectivity in high yield.

Dynamics And Catalytic Resolution Of Selected Chiral Organolithiums, Timothy Kum Beng

Graduate Theses and Dissertations

One of the most important developments of the last decade has been the emergence of new methods to dynamically resolve racemic organolithiums using stoichiometric amounts of the chiral ligand. When this concept is implemented successfully, it obviates the need for covalently attached chiral auxiliary based methods, asymmetric deprotonation, and asymmetric synthesis of a precursor stannane as ways to access enantioenriched organolithium compounds for use in asymmetric synthesis. Since certain electrophiles consume the chiral ligand, it is desirable to render this process catalytic in the chiral ligand.

As part of a larger study on the amenability of chiral organolithiums to a …

Direct Contact Pyrolysis Of Hydrocarbons: A Source Of Hydrogen And Interesting Carbon Formations, Peter G. Faught

UNLV Theses, Dissertations, Professional Papers, and Capstones

The work detailed in this document looks at a novel liquid metal supported catalytic system for the generation of hydrogen by decomposition of ethanol through direct contact pyrolysis. The hydrogen is produced at relatively low temperatures (500-600°C) and has carbon and water as co-products. It should be noted that CO is not observed as a product at these low temperatures. This is to be contrasted with the hydrogen produced at higher temperature from ethanol which does contain carbon monoxide. The presence of carbon monoxide in hydrogen complicates fuel cell operation and catalytic chemical processes. Thus, the lack of CO in …

Strategies For The Thermal And Photochemical Modification Of Gold Nanoparticles (Aunps) And The Fabrication Of Aunp Hybrid Materials, Hossein Ismaili

Electronic Thesis and Dissertation Repository

Among the existing approaches for the functionalization of the gold nanoparticle (AuNP), a direct interfacial organic reaction of terminal functional groups exposed on the surface of template nanoparticles with various reactants has been shown as a promising strategy to incorporate desired functionality onto the AuNP monolayer. In our own attempts to extend the types of reactions that can be utilized for efficient interfacial modifications of AuNPs, we examined uncatalyzed Huisgen 1,3-dipolar click-type cycloaddition of azide-modified AuNPs to terminal alkynes. These particular reactions were found to be generally too slow to be useful at ambient temperatures but it was shown that …

Homogeneous And Heterogeneous Approaches To 1,2,4-Triazine-Accelerated Copper-Catalyzed Azide-Alkyne Cycloadditions, Ashleigh Lauren Prince

Doctoral Dissertations

Over the last decade, the domain of click chemistry has grown exponentially and has significantly impacted the fields of organic synthesis, medicinal chemistry, molecular biology, and materials science. The ideal model of a click reaction has become the copper-catalyzed azide-alkyne cycloaddition (CuAAC). Inherent limitations of CuAAC, including high temperatures, long reaction times, and difficult purifications, have been minimized by the development of nitrogen-based ligands. Herein, we present a novel application of 1,2,4-triazines by investigating their use as accelerants for CuAAC.

A diverse library of 1,2,4-triazines were synthesized in order to examine the molecular determinants of their catalytic activity. These ligands …

Development Of Bifunctional Lysophosphatidic Acid & Lysophosphatidylcholine Activity Probes To Characterize Their Specific Binding Protein Receptors, Ritu Nandal

Masters Theses

Lysophosphatidic acid (LPA) and lysophosphatidylcholine (LPC) activity has been found to be dysregulated in cancer cells and therefore is a crucial target for research. Only a few LPA receptors have been identified to date, namely LPA 1, LPA 2, LPA 3, LPA 4 and peroxisome proliferator-activated receptors (PPAR). In order to identify receptors, we are designing and synthesizing bifunctional LPA and LPC activity probes to characterize their protein targets using activity based protein profiling (ABPP) among other proteomic technologies. By synthesizing bifunctional signaling probes that can mimic the naturally occurring LPA and LPC molecules and selectively capture receptors by virtue …

Conjugated Polymers And Inter-Chromophore Interactions: Synthesis, Photophysical Characterization And Application, Anshuman Mangalum

All Dissertations

Ever since the discovery of conducting polymers (CPs)in the late 1970s, organic conjugated materials and polymers is one of the most popular and fascinating research area among the scientists due to the remarkably unique properties and broad range of applications of (CPs), notably organic photovoltaic (OPVs), organic or polymer based light emitting devices (OLEDs / PLEDs), field effect transistors (FETs), nonlinear optical (NLO) devices and sensor for biologically relevant analytes, metal ions and anions. Optical properties of these materials depend on intra / interchromophoric interaction, geometry and relative orientation in space. Detailed study of such materials can also help us …

Double Helical Hydrogen-Bonded Aaa-Ddd Complexes And Supramolecular Polymers, Hong-Bo Wang

Electronic Thesis and Dissertation Repository

The design and characterization of linear oligomers that self-assemble into double helical structures has been a subject of interest to chemists since the elucidation of the double helix structure of DNA in 1953. Transition metal templates have been widely used in the construction of artificial double helical complexes from linear multidentate ligands. The use of other non-covalent interactions as the driving force in the self-assembly of these types of complexes is less common. Aromatic stacking interactions, anion templates, and salt-bridges have all been applied in this context. The great majority of these investigations have been concerned with the dimerization of …

The Nature, Origin And Preservation Of Amide Organic Nitrogen In Organic Matter, Georgina Anne Mckee

Chemistry & Biochemistry Theses & Dissertations

Past studies have found much of nonliving sedimentary/aqueous nitrogen-containing organic matter (NCOM) is composed of amides, assumed to be peptides/proteins. Their lability calls into question their survival, and several hypotheses have been suggested to explain this. Using Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) and nuclear magnetic resonance (NMR) spectroscopy I investigated the molecular amide composition in sedimentary/aqueous systems while reassessing their preservation and formation routes.

Development of a suitable methodology is essential for successful NCOM study due to electrospray ionisation source requirements: sediment samples need to be rendered into solution. Based on NMR and FT-ICR-MS analysis, I determined …

Insights Into Chemical Structure Changes Of Kerogen From Bituminous Coal In Response To Dike Intrusions Investigated By Advanced Solid-State 13C Nmr, Yuan Li

Chemistry & Biochemistry Theses & Dissertations

Variations in the chemical structures of kerogens From highly volatile bituminous coal located near two igneous dike intrusions in the Illinois Basin were examined in detail by advanced solid-state ¹³C nuclear magnetic resonance (NMR) spectroscopy. Spectral-editing techniques were used to identify specific functional groups. Direct polarization was used to quantify different functional groups. ¹H-¹³C two- dimensional heteronuclear NMR was used to examine connectivities and proximities, and ¹H-¹³C long-range recoupled dipolar dephasing was used to estimate aromatic cluster sizes. With decreasing distance to dike contacts and increasing thermal maturity (vitrinite reflectance R₀ from …

Development Of Two-Dimensional Gel Electrophoresis Procedures For Analysis Of Cupriavidus Necator H16 Subcellular Proteomes, Smita Joshi

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Smita Joshi on June 17, 2011.

Part A: The Use Of Nonionic Associative Polymers For The Thickening And Emulsifying Of Personal Care Products/ Part B: The Synthesis Of A Manganese Sod Mimetic For Reactive Coatings, Mallory Lynn Mcmahon

Master's Theses

Part A

The use of nonionic associative thickeners was proposed for personal care applications. Various limitations of current rheology modifiers used in personal care were discussed. Nonionic associative polymers were examined as both thickeners and emulsifiers. The structure/property relationship for nonionic polymers and their ability to thicken and emulsify were fully examined. Results showed an increase in thickening efficiency for nonionic associative polymers with higher log(P) (partition coefficient) values. This was due to the formation of smaller aggregates and increased bridging between aggregates. The connection between oil polarity, log(P) of the associative polymer, and emulsion stability showed no relationship however; …

The Preparation Of Functional Surfaces, Philip Thomas Dirlam

Master's Theses

Diels-Alder chemistry was utilized to manipulate the surface energy of glass substrates in reversible manner. Glass slides and capillaries were functionalized with hydrophobic dieneophiles resulting in a non-wetting surface. A retro Diels-Alder reaction facilitated by the thermal treatment of the surface’s function to cleave the hydrophobic dieneophile and resulted in the fabrication of a hydrophilic surface. Contact angle (CA) measurements were used as preliminary measurements for monitoring the changes in surface energy exhibited during the initial hydrophobic state (CA - 70±3°), after attachment of the dieneophile creating a hydrophobic state (CA - 101±9°) followed by reestablishment of the hydrophilic state …

Characterization Of Esterase Activity From The Bacteria, Francisella Tularensis, The Causative Agent Of Tularemia, Leigh Anna Weston

Undergraduate Honors Thesis Collection

Francisella tularensis is the bacteria responsible for causing the disease tularemia and is listed as one of the top three-biowarfare agents. Among the proteins essential to the virulence and infectivity of F.tularensis are multiple esterases, which are enzymes that break down various ester, thioester, and amide bonds. In this project, the catalytic activity, substrate speci fi city, and structure of a putative esterase from F.tularensis was studied. Latent fluorophores based on the molecule, fluorescein, were unmasked by the enzymatic activity of the esterase and the increase in fluorescence was measured over time to determine how well the e tcrase recognized …

Development Of A Green Method For Amide Synthesis, Megan Ruth Darragh

Undergraduate Honors Thesis Collection

The aim of this work was to determine the scope and limitations of using microwave technology, solvent-free conditions and green chemistry-applicable solid supports for amide synthesis. We hypothesize that the method developed by Comerford et al [12] may be applicable to other solid support systems already in use (silica, fly ash, and alumina), and that combined with the use of microwave technology, green and efficient synthesis of varied amides and other dehydration reaction products may be possible. These methods should show application to undergraduate, organic chemistry laboratories as well as large-scale production laboratories.

Chiral Recognition Study Of A Bimolecular Process In Amino Acid Chiral Ionic Liquids, Laurel Millikan Heckman

Undergraduate Honors Thesis Collection

In this study, chiral ionic liquid (CIL) solvents were prepared and tested for their chiral discrimination ability by probing with luminescence quenching. The CIL's were also tested for their impurities, viscosity and density. These experiments will help to determine the ability of CIL's to act as solvents in asymmetric catalysis. The chiral ionic liquids in this study were composed of amino acid methyl ester cations and bis(trifluoromethane) sulfonimide or bistri flimide anions (i.e. I-alanine methyl ester bistriflimid e, d-alanine methyl ester bistr iflim ide and I-leuci ne methyl ester bistriflimde). Circularly polarized luminescence (CPL) and its quenching in the chiral …

Towards The Synthesis Of Alpha-Aminogalactosylceramides, Shaun C. Christian

Master's Theses

No abstract provided.

Fluorescent Receptors For Biomolecules, Chi-Linh Do-Thanh

Doctoral Dissertations

The development of synthetic receptors capable of high-affinity complexation of biologically relevant analytes in competitive solvent systems represents an ongoing challenge in molecular recognition. Anion recognition is particularly problematic, which is significant since numerous biological processes are regulated by anions, such as those resulting from phosphorylation. In this dissertation, we present the design and synthesis of a fluorescent sensor containing two cyclen groups that are preorganized to form a binding cleft for anion complexation. The receptor design includes a rigid acridine backbone, which is also exploited for fluorescence signal transduction. Furthermore, click chemistry is employed to facilitate receptor synthesis, and …

Targeting A-Form Nucleic Acids: A Neomycin Based Approach, Nicholas Shaw

All Dissertations

This manuscript reflects our most recent advancements in the recognition of nucleic acids. Chapter one focuses on previously established methods in nucleic acid recognition. Nucleic acid targeting by small molecules affords a unique way to potentially inhibit biological functions, which is different from targeting enzyme and protein bio-macromolecules. We seek to further develop an aminoglycoside approach to targeting nucleic acids. Since aminoglycosides were first introduced, over 60 years ago, as treatment for tuberculosis, natural product discovery and demands for therapeutically more effective aminoglycosides, with lowered toxicity, have dominated the landscape of aminoglycoside research. More recently, our group has established neomycin …

Adsorbents With Chemically Bonded Saccharide Surfaces: Synthesis And Application For Stereoisomer Separation And The Synthesis Of Chiral Porous Silicas Using Templates Chiral Surfactant, Edwin Vega

Seton Hall University Dissertations and Theses (ETDs)

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Exfoliated Graphite Nanoplatelet-Filled Impact Modified Polypropylene Nanocomposites, Alex Duguay

Electronic Theses and Dissertations

Exfoliated graphite nanoplatelets (xGnP)-filled polymer composites have demonstrated superior electrical, mechanical, physical and thermal properties and are becoming a major focus for both academic and industrial research and development (R&D) activities. The main objective of this study was to characterize the influence of xGnP particle diameter, filler loading and the addition of coupling agents on the mechanical, rheological and thermal properties of xGnP-filled impact modified polypropylene (IMPP) composites. IMPP is currently being used at the AEWC Advanced Structures and Composites Center in polymer impregnated (pre-preg) fiber reinforced polymer (FRP) tapes consisting of an IMPP matrix polymer and E-glass continuous fibers. …

Scope And Mechanistic Studies Of The Palladium On Carbon Catalyzed Suzuki Cross Coupling Reaction, Carl Leblond

Seton Hall University Dissertations and Theses (ETDs)

No abstract provided.

Self-Assembling Organic Semiconductors With Tunable Electronic Properties Based On Novel Asymmetric Phenazine And Bisphenazine, Kyoungmi Jang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Current demands in the area of organic semiconductors focus on both electronic and self-assembling properties. Particularly, one-dimensionally grown nanostructures of small organic semiconductors have drawn much attention for nanodevice fabrication. Self-assembly through various intermolecular interactions has been widely used to produce one-dimensionally grown nanostructures which can be induced by various methods such as rapid solution dispersion, a phase transfer method, vapor annealing, crystallization, and organogelation in conjunction with proper molecular design. Controlling the morphology of the nanostructures plays an important role in achieving desirable properties in optoelectronic device applications. While significant advancements have been made in developing molecular architectures for …

The Design And Synthesis Of Different Α-Linked Galactose Disaccharides, Robert Anthony Simion

Chancellor’s Honors Program Projects

No abstract provided.