Chemistry Commons^™

Fourier-Transform Microwave Spectroscopy Of Cyclopropylmethylgermane And Van Der Waals Complexes Of Fluorinated Methanes, Michal M. Serafin

Masters Theses

Background theory and instrumentation utilized in the Fourier-transform microwave spectroscopy technique is first introduced followed by the structural and dynamic determination of cyclopropylmethylgermane and two weakly bound van der Waals complexes (difluoromethane-OCS, and fluoromethane-OCS). The minimum energy configuration has been determined for cyclopropylmethylgermane molecule, which has been shown to be the gauche configuration. Internal rotation parameters have been obtained from the rotational spectra of cyclopropylmethylgermane. The rotational spectra have been acquired for difluoromethanecarbonyl sulfide and fluoromethane-carbonyl sulfide and experimental structures have been determined for these weakly bound complexes. Evidence for a very low barrier to internal rotation has been observed …

Synthetic Studies Towards The Stellettins, Tung Yin Lin

Masters Theses

The synthesis of the stellettins, differing in the side chain at the C-13 position of the tricyclic region, was attempted by attaching the C-ring to a Wieland-Miescher ketone core using 1,3-bisphosphonoacetone. The decalin precursor was prepared in 35% from condensing ethyl acetate with acrolein, and a MnO2 oxidation, but too little material was obtained to cyclize this into the decalin. An alternative route involving a 2-step Robinson annulation of 2-methyl-1,3 cyclohexanedione with ethyl or methyl vinyl ketone and L-phenylalanine catalysis, followed by protecting C-9 carbonyl with acetal, gave 29% and 14% yields respectively.

1,3-Bisphosphonoacetone was prepared m a 3-step synthesis …

Synthesis And Characterization Of Ruthenium Bipyridyl Complexes For Detecting Nerve Gas Agents And Explosives, Arambe Gedara Aruna Weerasinghe

Masters Theses

Five novel 2,2 '-bis bi pyridine Ru(II) complexes have been synthesized and characterized using ¹H NMR, ¹³C NMR, ¹H-¹H-COSY, elemental analysis, fast atom bombardment or electrospray mass spectra and electronic absorption spectroscopy. Binding of Ru (11) complexes with nerve gas analogos such as diethyl chlorophosphate (DCP), dimethyl methyl phosphonate (DMMP) and hydrolyzed product (HCl) has been investigated by electronic absorption, fluorescence, and lifetime studies. Compound 1 showed a quenching in ³MLCT emission after an initial increase in intensity upon the addition of DCP with a bathochromic shift of 25 nm. Compound 2 exhibit a …

Design Of Multi-Electron Transfer Catalysts For The Reduction Of Trichloroethylene, Christopher Gerard Eman Ciptadjaya

Masters Theses

For decades, organohalide (RX) compounds have been heavily used in the chemical and pharmaceutical industries and in agriculture as pesticides. Improper disposal of organohalides has resulted in their presence in the environment as pollutants, and they have therefore presented serious environmental and toxicological concerns. These organohalides have been associated with various health and environmental problems. Therefore, effective methods for their remediation are required. We have developed a multi-electron transfer (MET) catalyst consisting of flavin mononucleotide anchored to nanocrystalline mesoporous titanium dioxide (TiO₂) thin films, and examined its reactivity toward the organohalide pollutant trichloroethylene (TCE). Various environmental factors were …

Nanomaterial Composites For The Detection Of Nerve Gas Analogs, Yogesh Datar

Masters Theses

The basis of the research work described here is the use of nanocomposite materials built by bottom-up approach for the selective detection of nerve gas analogs. Nanocomposites materials constructed by using nanoparticle-monomer-receptor (NMR) concept have been utilized to detect nerve gas analogs DCP and DMMP. Synthetic approach used in the construction of nanosensors involved use of robust platforms such as silica nanoparticles and fluorescent quantum dots. Highly conjugated receptor molecules were synthesized by using stilbeneoid compounds. A complete opto-nanosensor was developed by anchoring highly conjugated receptor molecules onto the silica nanoparticles as well as onto the quantum dots. The opto-nanosensors …

Fundamental Investigation Of Vesicle Bilayer Membrane Dynamics, Wilson Okumu

Masters Theses

We studied the bilayer of vesicles from dimyristolyphosphatidylcholine (DMPC), using nitrobenzoxadiazole (NBD) probes, attached to the head (NBD-PE) and the tail (NBD-PC) of phospholipid derivatives. We characterized the bilayer as it underwent reversible transition from the gel to the fluid through a phase transition range. The main phase transition was characterized by steady state and timeresolved fluorescence anisotropy, fluorescence intensity decrement and kinetics of dithionite reduction. We also studied DMPC with dihydrocholesterol. Differences between the surface and interior regions of the bilayer region were obtained. The activation barrier was enthalpic in the gel, entropic in the fluid phase and anomalous …

Nanosensors For The Detection Of Nerve Agents And Explosives, Deepak Kumar Thimmaraju

Masters Theses

The central hypothesis of this research was development of a novel nanosensor for the detection of nerve agents and explosives. The nanosensor assembly comprises a bottom up approach with nanoparticle (N), monomer (M), nanomolecule (N) and a receptor (R) as moieties of a NMNR assembly. My research was focused on evaluating receptors for their efficiency towards the target analytes such as nerve agents and explosives. Pi electron rich receptor 2-Phenyl-2-Propanol and its fluorinated analog 1,1,1,3,3,3-Hexafluoro-2-Phenyl-2-Propanol were investigated for their ability to detect nerve agents such as DCP, its analogs DMMP and HCl along with the explosives mono, di, and trinitrotoluene. …

Synthesis And Characterization Of Doped Core/Shell Quantum Dots, Elizabeth J. Sodt

Masters Theses

The central theme of the research performed is the systematic modification of the optical properties of quantum dots by the formation of a shell of another quantum dot of a different band gap energy. Core/shell quantum dots such as CdS:Mn/CdS, CdS:Mn/ZnS, and ZnS:Mn/CdS with various concentrations of dopant Mn²⁺ in the core and shell concentrations have been synthesized under mild conditions in the aqueous phase using stoichiometric amounts of the surfactant stabilizer dodecyl sulfate. These quantum dots exhibit UV-vis, emission, and electron paramagnetic resonance (EPR) spectral behavior that is dependent on the concentration of the shell and the dopant …

Nitrogen Heterocyclic Compounds As Receptors In Nanosensors For Nerve Gas Agent Analogs, Swapna Katram

Masters Theses

The research is focused on developing nanosensors consisting of different components that are chemically linked, namely, nanoparticle, fluorescent monomer, and receptor (NMR sensors) and nanoparticle, monomer, nanomolecule, and receptor (NMNR sensors) for the sensitive and selective detection of nerve gas agents. These sensors detect the target toxins by fluorescence change which is amplified by signal transduction. Model nerve gas toxins (DCP) and (DMMP) and HCl were employed as analytes, and the nitrogen heterocyclic compounds, 5-aminoindazole and dipyrido[3,2-a:2',3'-c]phenazine (dppz) as receptors in the NMR and NNMR nanosensors. The monomers were (E)-4-(4- formylstyryl) benzoic acid (NMR sensor) and 2-mercaptosuccinic acid (NNMR sensor). …

Biochemical Characterization Of Disease-Causing Mutation In N-Terminal Wilson Protein Domain Six, Patrick Ochieng

Masters Theses

Wilson protein (ATP7B) is a copper-transporting P-type ATPase that regulates copper homeostasis and secretion of copper-containing enzymes in the liver. In hepatocytes, ATP7B delivers copper to apoceruloplasmin and mediates the excretion of excess copper into bile. Mutation in the gene coding for Wilson protein leads to Wilson disease. Several mutations in Wilson protein have been identified and of particular interest, mutations affecting the N-metal binding region significantly interfere with the ability of Wilson protein to transport copper to its target in the copper-trafficking pathway. In an attempt to characterize the disease-causing mutation (G591D) in Wilson protein domain 6 (WLN6), we …

Development Of Scanning Electrochemical Microscopy For Studying Electron Transport In Lipid Monolayers And Gold Nanoparticle Films, Violeta Stoycheva

Masters Theses

The focus of this thesis is the scanning electrochemical microscopy (SECM) investigation of the electron transport in lipid monolayers and in films of gold nanoparticles. The quality and stability of lipid monolayers were characterized by various analytical techniques such as fluorescence microscopy and spectroscopy, contact angle, and electrochemistry using a monolayer modified electrode. In the SECM measurement, the monolayer electron transport was not detected. The microscopic monolayer quality turned out to be not suitable for studying the electron transport.

The conductivity of mono layer protected gold clusters (MPCs) with different core sizes (1-3 nm diameter) were investigated using SECM. These …

Transcriptional Regulation Of Glucose-6-Phosphate Dehydrogenase (G6pdh) By Glucose, Pramod U. Thekkat

Masters Theses

In liver, insulin and glucose regulate the expression of important genes for lipid and carbohydrate homeostasis. Studies on the effects of glucose and insulin, including effects on cell signaling, are vital since deficiencies in glucose utilization in cells and/or insulin secretion contribute to conditions like obesity and diabetes. In liver, the pentose phosphate pathway is one of the primary pathways that can utilize the excess carbohydrate. Glucose-6-phosphate dehydrogenase (G6PDH) is an important rate limiting enzyme in this pathway. Our laboratory has shown that both insulin and glucose induce the expression of G6PDH, although the mechanism by which this transcriptional regulation …

Heterogeneous Formation Of Hono On Hno3 Pre-Conditioned Hydrophobic, Hydrophilic And Ionic Surfaces At Various Relative Humidities, Dustin S. Wier

Masters Theses

Nitric acid (HNO₃) is a major sink for NO_x (NO+NO₂ ) and is known to be removed from the atmosphere as a result of wet and dry deposition where it is then deposited on various surfaces in the environment. As these surfaces are photolyzed HONO is produced which affects the overlying troposphere. This study examines the amount of HONO (Nitrous Acid) produced by the photolysis of adsorbed HNO₃ as a function of changing relative humidity on hydrophobic, hydrophilic, and inorganic ionic salt surfaces. The amount of HONO produced was measured in long path cell using …

Physicochemical Properties Of Individual And Mixed Oxides Of Sio2, Al203, Tio2‚ And Photocatalytic Behaviour Of Organosilane Modified St Samples, Kalyani Gude

Masters Theses

A variety of oxides such as silica, alumina, titania and mixed oxides such as silica/alumina (SA), silica/titania (ST) and alumina/silica/titania (AST) are investigated by TGA and FTIR. These mixed oxides are analyzed because of their applications as catalysts. Thermogravimetric analysis is done on all the samples to determine the temperature at which the weakly adsorbed water is lost and the surface is left with only surface hydroxyls. TGA data showed the loss of most of the adsorbed water at around 100°C.

From the diffuse reflectance FTIR spectra taken at 200 and 300°C the silanol content is estimated from the 3740 …

Zinc(Ii) Incorporation Into Porphyrin Cytochrome C As A Function Of Temperature, Urea Concentration And Zinc(Ii) Acetate Concentration And The Urea And Guanidine Hydrochloride Induced Unfolding Of Porphyrin Cytochrome C, Sireesha Potula

Masters Theses

The objective of this thesis is to address the question of whether the removal of the native iron(II) ion in cytochrome c (cyt c) and substitution by a different metal ion affects the overall structural stability. We have studied the incorporation of zinc(II) into metal-free porphyrin cytochrome с (H2cyt) and investigated the structural stability of cyt c in the absence of the iron(II) ion and in the presence of the zinc(II) ion by different spectroscopic techniques. Compared to H2cyt, zinc-substituted cytochrome c (Zncyt) has a significantly different absorbance spectrum, so we monitor over time the change in absorbance upon addition …

Metal-Substituted Cytochrome C: Manganese (Ii) Incorporation Kinetics And Structural Stability Studies Of Native Iron Cytochrome C, Porphyrin Cytochrome C, Zinc Cytochrome C And Manganese Cytochrome C, Vineela Gundala

Masters Theses

Metalloproteins have the capacity to bind various metal ions. In spite of this seemingly diverse choice of cofactors, metalloproteins generally bind only their cognate metal in vivo. Cytochrome c (cyt c) binds Fe porphyrin in vivo. The main objective of this thesis is to investigate why nature selects Fe porphyrin as the prosthetic group in heme proteins and how removal of the native Fe in cyt c and substitution by different metal ions affects the local coordination environment, overall structural stability, and biological function. Our goal is to prepare and characterize metal-free cytochrome c, socalled porphyrin cytochrome c (H2cyt), and …

Physical Analysis Of Human Hair, Lea Marie Dankers

Masters Theses

"Physical analysis of human hair has been performed to determine the effects of chemical treatments on hair samples. Five samples including an untreated sample were analyzed using various methods. The methods included differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and carbon-13 cross polarization/magic-angle spinning nuclear magnetic resonance (¹³C CP/MAS NMR)"--Abstract, page iii.

Supramolecular Usefulness Of Hexamethylenetetramine, Philias Daka

Masters Theses

Because non-covalent contacts are important to the design and construction of materials with functional applications, efforts that seek to uncover chemical features responsible for the assembly of multimolecular arrays hold current interest. The building-block approach is one strategy that has been successfully employed for the construction of molecular assemblies. By designing molecular components with complementary functional groups, the construction of predictable supramolecular motifs is possible. Although various modes of molecular alignment have been generated using this strategy, the extension of low dimensional motifs (discrete and 1-D patterns) to 2- and 3-D patterns remain a current challenge.

Studies Directed Toward The Diastereocontrolled Synthesis Of Heritol, Prashanth K. Padakanti

Masters Theses

3,3-Dichloro-4-indanyloxetan-2-one was synthesized and its double ring expansion in the presence of the Lewis acid magnesium bromide was investigated, which resulted only in a trans-fused butyrolactone in 25% yield. Of the natural products containing butyrolactones fused to 6-membered rings, trans is more common. This method of double ring expansion can be applied to the synthesis of the natural product heritol, whose core structure contains the butenolide moiety. A model study of the double ring expansion was performed with 3-chloro-4-indanyl-3-methyloxetane-2-one B6, but this study was not completed.

In order to apply the double ring expansion methodology to synthesize heritol, the preparation …

Expression And Characterization Of Hyperthermophilic Aqujfex Pyrophilus Flagellin Protein In Mesophilic Bacterial Systems, Srivani V. Mukkamala

Masters Theses

The structural protein flagellin, FlaA derived from hyperthermophilic Aquifex pyrophilus, a rod shaped eubacterial species that grows near hydrothermal vents at an optimum growth temperature of 85 °C forms elongated thermostable flagella nanotubes. FlaA was successfully over-expressed for the first time using pET28c plasmid in E. coli BL21 cells at 37 °C. The protein was isolated from inclusion bodies that were solubilized by alkaline pH, refolded by dialysis and purified by chromatographic techniques. The FlaA was characterized by fluorescence, light scattering and circular dichroism. The FlaA was not in the correct folded form to form flagella as efforts to …

Synthesis And Characterization Of Inosamines, Sing Raj Gurung

Masters Theses

This project is concerned with the preparation of scyllo-inosarnine hydrochloride 6, a biologically active compound, which bears six successive stereogenic centers. The synthesis of this compound would help elucidate the involvement of inosamines in biological nitrogen fixation. myo-Inositol served as the starting material to synthesize target compound 6. Regioselective protection and deprotection of myo-inositol provided azide 43 as key intermediate. In the final steps deprotection of five benzyl groups and reduction of azido group was achieved by catalytic hydrogenation. scyllo-Inosamine hydrochloride 6 was fully characterized by m.p., ¹H NMR, ¹³C NMR, IR, EA and via …

Coordination Environment: A New Approach To The Sensing Of Lead (Ii) Itself, Kristina Marie Nespechal

Masters Theses

Lead(II) is a silent poison that has plagued society since 3800 B. C. The average intake of lead in the United States alone is 50 μg per day, which is approximately 100-1000 times greater than that of prehistoric lead levels. Regardless of the banning of lead in paints and gasoline, lead poisoning prevails as a major environmental health risk. Science has the ability to address the concern with this environmental contaminant. The future production of an economical and reliable test kit for lead(II) relies on the luminescence of the heavy metal itself.

The absorption and emission spectra for a series …

Spectroscopic Investigation Of Metal-Substitution Of Cytochrome C, Deepthi Kandi

Masters Theses

We study, by absorbance spectroscopy, the incorporation of various metal ions (Cu²+ and Zn2*) into metal-free porphyrin cytochrome c (H₂cyt) as well as the various conformational forms of metal-substituted cytochromes. The H2cyt and desired metalsubstituted cytochromes have significantly different absorption spectra, providing a simple means of monitoring the incorporation of Cu²* or Zn2* into the empty porphyrin prosthetic group. The rates of metal-ion incorporation were studied under protein denaturating conditions using chemical denaturants, like urea and guanidine hydrochloride (GuHCI), and temperature that partially and completely unfold H2cyt, facilitating the incorporation of a metal ion. Moreover, the structural stability of copper …

The Study Of Carbon Acylation Of Highly Delocalized Enolates Using Catalytic Dmap On 3-Phenyl Benzofuranone Derivatives, Xiguang Zhao

Masters Theses

Benzofuranones along with their derivatives compose a diverse array of natural products and drugs, and show a wide variety of biological effects. Several synthetic methods have been published that describe the preparation of 2-(3H)-benzofuranones having mono alkyl or aryl substituents attached to the fused furanone ring with moderate to high yields. To date, reports describing the preparation of disubstituted 2-(3H)-benzofuranones, especially with one acyl group, are rare. Early approaches are limited by low yields, economical expenditure and environmental risk.

Direct acylation of benzofuranones consistently provides O-acylated isomers rather than C-acylated isomers, which are desired products in the great majority of …

Cloning, Overexpression, Purification And Characterization On N-Terminal Metal Binding Domains 5 And 6 Of Wilsons Disease Protein, David Achila

Masters Theses

Wilsons disease is an autosomal recessive disorder of copper metabolism which results from mutations in the gene encoding for Wilson disease protein (WDP). The cytosolic N-terminus of WDP comprises six metal binding domains each containing a conserved metal binding motif, GMXCXXC. The contribution of these metal binding domains to copper homeostasis is poorly understood. We have cloned, expressed and purified residues 485 to 633 corresponding to N-terminal metal-binding domains 5 and 6 of WDP (WD5-6). Two of the 3 disease causing mutations in the N-terminal metal binding domains of WDP occur one in each of these domains and the two …

Systems For Predicting Pitzer’S Ion-Interaction Model Parameters, Theresa Balderas Obias

Masters Theses

Pitzer's Ion-interaction Model had been widely used in predicting the non-ideal behavior of solution over a wide range of conditions for natural water systems. The model is successful only when there are sufficient parameters available. However, generating these needed parameters requires a great quantity of work and it would be advantageous to be able to predict the Pitzer's parameters for salt systems when there is no data available.

This research entailed the development of ionic radii dependent equations for Pitzer's binary ion-interaction parameters β_MX⁽⁰⁾, β_MX⁽¹⁾, β_MX⁽²⁾, and C^ϕ_MX . …

Structure-Activity Relationship Studies On Thioxolone Compounds As Inhibitors Of Human Carbonic Anhydrase Ii, Jared Nyabuto Orwenyo

Masters Theses

Carbonic anhydrase II (CA II) is a zinc metalloenzyme that catalyzes the reversible hydration of carbon dioxide. The role of this reaction in physiology has made it a target of many therapeutic approaches. Most CA II inhibitors currently known are sulfonamide-based and this is the only functional group incorporated into rationally designed CA II inhibitors. Thioxolone (6-hydroxy-1, 3-benzoxathiol-2-one), is a non-sulfonamide that has been found to have CA II inhibitory activity.

Thioxolone and its analogs were studied to evaluate the inhibition activity that can be achieved upon modification of the thioxolone molecule. IC₅₀ values and dissociation constants were determined …

Design, Synthesis And Characterization Of Nanosensors For Nerve Gas Agents, Thushara Gunasinghe

Masters Theses

This research is focused on the design synthesis and characterization of nanosensors to detect the nerve gas agents such as sarin at very low concentration levels (parts per billion and lower) which is very important to combat terrorism. Nanosensors constructed by the bottom up approach could provide the low sensitivity levels and high selectivity required for nerve gas detection. The sensing mechanism exploits the inherent properties of nanomaterials and signal amplification by signal transduction. The components of a nanoparticle-fluorescent monomer-nanomolecule-receptor (NMNR) sensor have been designed, synthesized, and characterized successfully. Interaction of the components of NMNR sensor with a model nerve …

Ionic Liquid As Catalysts In The Cycloaddition Of Co2 To Styrene Oxide In Supercritical And Subcritical States, Joy Mwalimu

Masters Theses

Supercritical fluids (SCFs) have fascinated researchers ever since the discovery of a critical temperature more than a century ago.¹ Initial studies focused mainly on the physical properties of supercritical phases.² However, their use as reaction media has sparked mainly during the last five to ten years.²

The coupling of CO₂ and Ionic Liquids (ILs) in the synthesis of cyclic carbonates comes from an increasing need for environmentally and toxicologically benign processes for the production of high-value compounds. In my research, CO₂ was utilized as both a replacement solvent and a C₁ feedstock in its …

Synthetic And Structural Studies Of Novel 1, 10-Phenanthroline Derivatives, Eunjoo Kim

Masters Theses

Asymmetric catalysis can provide a general approach to the preparation of enantiomerically enriched compounds in organic synthesis. Very often these asymmetric catalysts consist of a chiral ligand-metal complex. Because of the growing demand to develop enantioselective reactions in organic chemistry one focus of this area of research is the design and characterization of new chiral ligands for asymmetric synthesis.

The focus of my research is in the design, synthesis, and characterization of novel 1, 10-phenanthroline derivatives that could be used as chiral ligands in enantioselective reactions. Central to these studies have been the effect of substituents on the B-ring of …