Chemistry Commons^™

Rhizopine Synthesis – Potential Mediators For Nitrogen Fixation In Legume Plants, Venkat Reddy Guduru

Masters Theses

This research project focused on novel and efficient synthetic approaches of inosamine derivatives (rhizopines). The preparation of specific rhizopines would help elucidate the microbial pathway of rhizopine catabolism and degradation, and determine the role of corresponding genes during nitrogen fixation. We have investigated regio - and stereoselective transformations of myo-inositol derivative 28 utilizing an organostannane as key intermediate towards rhizopine 1a. The synthesis involved several protection and deprotection strategies to control competing reactivities of six hydroxyl groups of myo-inositol. Rhizopine 1a was prepared efficiently as a single isomer in 8 steps and 13% yield by controlling reactions …

Effect Of Antioxidants On Cadmium Induced Oxidative Stress And Signal Transduction, Deepti Goel

Masters Theses

A study was done to establish if reactive oxygen species (ROS) participate in the signal transduction pathway through which cadmium induces gene transcription. Cadmium has become a concern in the health care community in the past few years as evidence suggests that cadmium can induce the development of tumors, influence cell signaling and cause damage to organs, tissue, cells and DNA. The mechanism by which cadmium exerts its action on cellular processes or induces toxicity is however unclear although there is evidence to suggest that ROS play a role. Our laboratory is interested in understanding the mechanisms of differentially regulated …

Copper Exchange Studies Between The First And Fourth N-Terminal Metal-Binding Domains Of Wilson Disease Atpase, Jennifer Bunce

Masters Theses

The human copper-transporting ATPase Wilson's disease protein was one of the first proteins shown to be actively involved in cellular copper homeostasis. The protein includes six N-terminal metal binding domains. The individual capabilities of the domains to bind and transfer copper are not yet fully understood. Each metal-binding domain is about 72 amino acid residues long and contains the conserved binding motif GMTCXXC, of which the cysteines are involved in the copper coordination. Studies have shown that the protein binds six copper atoms suggesting the potential involvement of each metal-binding domain. Separate functional roles for the latter domains have been …

Nonaqueous Platination For Synthesis Of Platinated 7 Alpha-Substituted Estradiol, Sarah A. Mazzella

Masters Theses

Cisplatin, carboplatin, and oxaliplatin are used clinically for treating some cancers, but are they are not the preferred treatment for breast cancer. The usefulness of these platinum-containing drugs is limited by poor concentration of the active platinum moiety within the tumor before dose-limiting side effects are reached. One way to selectively concentrate a platinum antitumor compound in breast cancer cells is to conjugate the platinum moiety via a malonate linkage to an estrogen which selectively binds to the estrogen receptor (ER) protein. The major obstacle to linking a lipophilic estrogen to a diamino-platinum compound is the lack of solubility of …

The Application Of 31p And 1h Nmr Spectroscopy To The Study Of Freeze Tolerance And Freeze Avoidance In Biological Systems, Nicholas C. Wright

Masters Theses

31P NMR spectroscopy was used to study freeze tolerance of the wood frog, R. sylvatica. Spectra were obtained of living whole body samples and isolated thigh muscle tissue. These results were compared to R. pipiens which is freeze sensitive. R. sylvatica was found to have significantly higher levels of glucose-6-phosphate and several phosphodiesters. Both seasonal and environmental stresses were studied to determine the effect of freezing conditions on the phosphorus compounds present in R. sylvatica. The results show that R. sylvatica is capable of tolerating stresses that are associated with freezing without any drastic changes in the levels of metabolic …

Synthesis And Characterization Of A Recombinant Thrombin Inhibitor, Joel Lwande

Masters Theses

The final step of the blood coagulation cascade is catalyzed by thrombin, a serine protease. Like most enzyme activities, thrombin activity encounters inhibition from both direct and indirect inhibitors. A new thrombin inhibitor peptide named theromin was recently isolated from the leech Theromyzon tessulatum, and it is the most potent thrombin inhibitor isolated to date. Theromin is made up of 67 amino acid residues, out of which 16 are cysteines engaged in 8-disulfide bridges.

We synthesized the theromin gene and expressed the protein in Eschericia coli. We purified the recombinant protein and carried out thrombin inhibition assays that …

Metal Ion Imprinted Polymers For Biomolecular Recognition, Len A. Harris

Masters Theses

Protein recognition by HPLC, based on histidine residues, was achieved by incorporating a copper chelating ligand covalently bonded to a polystyrene/divinyl benzene substrate, into column packing. The metal ion was bonded to the substrate in two ways: randomly, where the copper was bound to the ligand after the substrate polymerization and imprinted, where the copper was bound to the ligand before the substrate polymerization. The effect of this templating was measured by protein separation parameters of the resulting HPLC chromatographs. The hypothesis of this thesis is the imprinted substrate will have a higher copper content, and with coppers affinity toward …

Iron-Promoted Remediation Of Atrazine: Solution And Amended Sandy Column Studies, Donghua Zeng

Masters Theses

No abstract provided.

Electron Transfer In Phosphido-Bridged Complexes, Pradeep N. Perera

Masters Theses

No abstract provided.

Physiology And Biochemistry Of Sclerotinia Sclerotiorum, A Fungal Plant Pathogen, Erastus Gatebe

Masters Theses

No abstract provided.

A Comparative Study Of Photomultiplier Tubes And Charge Coupled Devices In Glow Discharge-Optical Emission Spectrometry, Robert James Broadwater

Masters Theses

This Masters Thesis compared two glow discharge-optical emission spectrometers designed around two different types of detectors: the photomultiplier tube (PMT) and the charge-coupled device (CCD). The two instruments compared were the LECO SA2000 (PMT-based) and the LECO GDS500a (CCD-based). Detection limit, dynamic range, precision, accuracy, and drift were determined to compare the detection systems between 165 and 450nm.

The PMT-based system outperformed the CCD-based system in all five of the categories studied based on the initial protocol. However, it was shown that improvements could be made in four of the five categories studied by exploiting the CCDs ability to monitor …

Capillary Electrophoretic Separations Of Metal Ions, Elena Hofman

Masters Theses

Transition-metal (Zn(II), Co(II), Ni(II) and Cu(II)) ion separation was studied using 8-hydroxyquinoline-5-sulfonic acid and 2-methyl-8-hydroxyquinoline ligands with surfactants (cationic and anionic) by capillary electrophoresis under a variety of conditions (like pH, ionic strength, voltage and ion, ligand and surfactant amounts) and has debuted a clear separation mechanism. With cationic surfactants, ligands compete with capillary surface silanols for the metal ions; with anionic surfactants, ligands, silanols and micelles compete.

An empirical parameter, K_e, (electrophoretic-mobilities based) rationalizing the separation was proposed, experimentally analyzed and supported; it provides a silanol group per cm² value of the capillary surface, an equilibrium …

Chlorobenzenes And Chloronitrobenzenes Interaction With Iron (O), Manuel Alejandro Serratos

Masters Theses

Degradation of chlorobenzene, dichlorobenzenes and chloronitrobenzenes (ClB, x-Cl2B and x-ClNO2B) was tested by trying to make them react with metallic iron, Fe (0), in water solvent.

The experiments consisted of optimizing the parameters of the reactions (like minimum mass of iron needed) and analytical detection conditions. Analytical techniques used were gas and liquid chromatography (GC and HPLC), mass spectrometry (MS) and UV-Vis spectroscopy.

No substances other than the initial ClB and x-Cl2B were detected in their tests with Fe (0) after shaking for periods of up to three days, although 10%weight average decreases in concentration were observed.

The ClNO2B isomers …

Synthesis And Characterization Of A Polypyridyl Ru(Ii)-Alloxazine Complex For Adsorption On Tio2-Coated Ito Electrodes, Manisha A. Patel

Masters Theses

TiO₂-coated conducting glass electrodes can be modified by attachment of redox-active molecules to the TiO₂ surface. This thesis describes the synthesis and characterization of a polypyridyl Ru(II) complex that can be covalently bound to a TiO₂ surface through the carboxylate groups of 2,2'-bipyridine-4,4' -dicarboxylic acid, H₂dcbpy. In addition, the bound complex contains a redox-active alloxazine derivative, pptd, which is capable of 2e^-/2H⁺ transfers. Thus the TiO₂-coated electrode is modified with a transition metal complex capable of shuttling H-atoms to substrates in solution. Synthesis of the PF₆^- salt …

Phosphido-Bridged Complexes Linked By Unsaturated Phosphines, Yong Liu

Masters Theses

Di(p-tol)phosphido-bridged complexes, (OC)₄M[μ-P(p-tol)₂]₂M(CO)₄ (M = Mo, W), have been synthesized for the first time. These have been obtained from the reaction of (OC)₅MP(p-tol)₂H with BuLi, followed by air oxidation. The choice of solvent is very important as the intermediate anion, [(OC)₅MP(p-tol)₂] is unstable in THF. An ideal solvent for these preparations is CH₃OCH₂CH₂OCH₃ (monoglyme) from which yields of 68% and 76% were realized for the tungsten and molybdenum complexes, respectively. …

Dmap As A Catalyst For Carbon Acylation: Elucidation Of Mechanistic Pathway, Including Spectral Characterization Of The Putative Reactive Intermediate, Jagadish K. Boppisetti

Masters Theses

3-Phenylbenzofuranone, when deprotonated with sodium hydride, forms an extended enolate system which, when treated with excess alkyl chloroformates, affords only oxygen-acylated products, as opposed to the usually desired carbon-functionalized derivatives. It was discovered that such molecules, when treated with a catalytic amount of 4- (N, N-dimethylamino)pyridine (DMAP), rearrange quantitatively to the carbon acylated isomers.

These migrations, which are accompanied by a deep blue color, are proposed to involve a reactive intermediate. This intermediate, which is postulated as an ion pair charge transfer (IPCT) complex, has been closely studied in order to gain a better understanding of the …

The Synthesis Of 2-(1-Indenyl)-Phenol: A Potential Ligand For Metallocene Polymerization Catalysts; And, Ω-Iodoalkyl(Methyl) Malonate Esters: Synthesis And Application In Bioconjugate Chemistry, Sara E. Bendler

Masters Theses

Chapter I:

Metallocene catalysis is an important division of polymerization chemistry. The design of appropriate ligands for metallocene catalysts has focused on stereochemical control and structural diversity. The synthesis of the potential ligand 2-(1-indenyl)-phenol has been developed. Indenyl phenol ligands offer advancements over cyclopentadienyl ligands because the steric and electronic properties of the catalyst could be tailored to suit individual polymerization reactions. 2-(1-Indenyl)-phenol was synthesized with an overall yield of 4% and characterized with ¹H NMR and ¹³C NMR.

Chapter II:

A large percentage of breast malignancies overexpress the nuclear estrogen receptor (ER) protein. Binding to nuclear receptors …

Mechanistic Studies On The Antagonistic Effect Of Chromium On Bpde Mutant Frequency In Human Fibroblasts, Felicia Codrea

Masters Theses

The purpose of this study was to investigate the possible mechanisms involved in the decrease in mutant frequency when cells are treated with two different types of carcinogens: chromium (VI) in combination with benzo(a)pyrene diol epoxide (BPDE). Three of our working hypotheses are: Cr alone or Cr and BPDE synergistically activate detoxifying enzyme glutathione-S-transferase (GST), Cr alone or Cr and BPDE act synergistically to inhibit cell cycle at the G₁/S boundary thus allowing more time for DNA repair, and Cr alone or Cr and BPDE synergistically activate DNA repair systems which result in more efficient repair of DNA …

Metal Ion Separation Mediated By Organized Molecular Assemblies, Hong Cao

Masters Theses

We have investigated the separation of Co(II), Ni(II), Cu(II) and Zn(II) by the ligands 8-hydroxyquinoline- 5-sulfonic acid and 7-iodo-8-hydroxy-quinoline- 5-sulfonic acid in the presence of the anionic surfactant sodium dodecyl sulfate (SDS) and the cationic surfactant octyltrimethylammonium bromide (OTAB) . Baseline separations have been achieved by HPLC employing an octadecylsilanized silica (ODS) column. The underlying mechanisms of separation have been determined.

The significant new results of our studies are: (1) separation is not possible without the presence of surfactants and hence organized assemblies; (2) separations can be achieved under submicellar concentrations; (3) the separations are not driven by micelles; and …

Separation Of Enantiomers With Chiral Dendrimer, Jie Zhuang

Masters Theses

Chiral dendrimers with .unique ordered structures are especially attractive for the recognition of chiral molecules based on the three point contact model. We have successfully synthesized first generation chiral dendrimers containing L- and D- tryptophan methyl ester moieties and characterized them by NMR, IR, UV-Visible, MS, and optical activity. L-tryptophan methyl ester dendrimer was converted to its acid form in order to attach it to aminopropyl silica for the HPLC separation of enantiomers. The aminopropyl silica containing 1.52mmols/g of NH₂ groups binds about 0.3mmols of dendrimer per gram and has about 0.4mmols of free NH₂ groups per gram. …

Glass Transition Behavior Of Thin Poly(Methyl Methacrylate) Films On Silica, Moses T. Kabomo

Masters Theses

"Modulated Differential Scanning Calorimetry (MDSC) was used to study the glass transition behavior of poly(methyl methacrylate) (PMMA) adsorbed onto silica substrates from toluene. Untreated fumed amorphous silica and silica treated with hexamethyldisilazane were used for the adsorption to probe the effect of polymer- substrate interactions. To test the effect of molecular weight on the T_g of adsorbed polymers, low polydispersity PMMA samples of varying molecular weights were used. The results revealed a broadening of the glass transition towards high temperatures. The observed increase in the glass transition breadth varied with adsorbed amount and the type of silica used for …

Pan, Ppn And Mpan Measurements And The Quantitative Relationship Of Pan And Mpan In Biogenic Hydrocarbon Conditions, Chen Wangchun

Masters Theses

Simultaneous measurements of PAN, PPN and MPAN were made during the SOS 1999 Nashville campaign at Dickson site. The PANs data at this site were rich and complex. PAN and MP AN showed obvious diurnal change but PPN did not during this period. PAN and ozone have a clear positive relationship. Due to the special location of the site, winds from different directions bring anthropogenic hydrocarbons (AHCs) or biogenic hydrocarbons (BHCs) to the site. The data showed that the influence of AHCs and BHCs on PANs compounds varied on different days. Average values of PAN/PPN and PAN/MPAN from MLR may …

Characterization Of Organo-Tin And Organo-Mercury Compounds With Electrospray Mass Spectrometry, Kan Zhu

Masters Theses

Metal-containing compounds are often found as pollutants in the environment. Obtaining speciation information about these compounds is important to understanding toxieity and bioaccumulation. Electrospray Mass Spectrometry (ESMS) is a technique that has the potential to provide rapid and direct speciation information of solution phase metal compounds. The ionization behavior of chemical species is related to their electron affinities. The higher the electron affinity, the easier it will be reduced during the ionization process. Additionally, solvent with different polarity and surface tension will also affect the ionization and reduction products. Organo-tin compounds with more alkyl groups will be ionized more efficiently, …

Alkyl Nitrates In Dickson During The Sos 1999 Field Campaign, Mei Ma

Masters Theses

Measurements of alkyl nitrates were performed during the Southern Oxidants Study (SOS) 1999 Summer Field Campaign in Dickson, TN from June 10 to July 15, 1999. The developed GC-ECD method was tested and used successfully. Nine alkyl nitrates were measured and six alkyl nitrates were quantified. The measured alkyl nitrates expect methyl nitrate showed higher mixing ratios under northeasterly and southeasterly wind, which brought anthropogenic sources to the measurement site, and lower mixing ratios when wind came from northwest and southwest, which brought NOx and clean air, respectively. The contribution of the measured alkyl nitrates to the total oxidized nitrogen …

A Qualitative Investigation Of The Polymerization Process In The Ihss Humic Substances Extraction Procedure Using Model Phenolic Compounds, Roger J. Germay

Masters Theses

Achard (1786) extracted peat with alkali and reported obtaining dark compounds now called humic substances. These are complex, high molecular weight, polyphenolic compounds naturally occurring in soil, in fresh-water and in marine environments. They are biodegradation products of plant materials.

The International Humic Substances Society (IHSS) adapted Achard's method to separate humic substances into three fractions: (1) humic acids (HA), soluble only at high pH; (2) fulvic acids (FA), water-soluble at any pH; and (3) humin, insoluble at any pH. The IHSS method involves contact of soil with 0.1N.NaOH solution, followed by acidification with HCl.

In this study, 0.01 N. …

Surface Modification Of Diamond And Determination Of Kinetics And Mechanism Of Modification Reactions, Humera Farooq

Masters Theses

A series of photochemically modified diamond surfaces were prepared. Surface functional groups added included, chlorine, bromine, methoxy, amine, methylamine, dimethylarnine and trimethylammonium chloride. Photochemically chlorinated and brominated diamond surfaces were used as synthetic intermediates. The modified diamond surfaces were characterized by Diffuse Reflectance Infrared Spectroscopy (DRIFT) and X-ray Photoelectron Spectroscopy (XPS).

The study was mainly focused on understanding the kinetic processes and reaction mechanism of modified surfaces. The observed rate constants for surface hydrogen loss and HCl (g) evolution were found to be identical. Similar rate constants were observed for amine substitution and consumption of ammonia.

The study of action …

An Investigation Of Friedel-Crafts Alkylation Reactions In Super- And Subcritical Carbon Dioxide And Under Solventless Reaction Conditions, Kan Nie

Masters Theses

This study investigates the Friedel-Crafts alkylation reaction of triphenylmethanol with methoxybenzene (anisole) in supercritical and subcritical carbon dioxide, and under solventless reaction conditions. The reaction was initiated using trifluoroacetic acid to produce triphenylmethylcarbocation as the reaction intermediate. Isolated product yields of the Friedel-Crafts product, p-methoxytetraphenylmethane, are reported. The possibility of using the above reaction as an alternative synthesis in an undergraduate organic laboratory to teach some of the tenets of green chemistry is also presented. Additionally, we have investigated the use of benzhydrol, 9-hydroxyxanthene and 9-phenylxanthen-9- ol as potential carbocation sources for supercritical carbon dioxide synthesis and we report those …

Computational Studies Of Constant Bond Dissociation Enthalpy Ratios And Novel Structures For [H3, B, C, F]+, Le Li

Masters Theses

This thesis describes two separate computational chemistry projects. The first project is a study of constant bond dissociation enthalpy ratios, and the second project is a study of the rearrangement and fragmentation processes on the singlet potential energy surface of the [H₃, B, C, F]⁺ system.

G2 and G2(MP2) enthalpies have been calculated for isoelectronic AB₂ systems with singlet-linear, singlet-nonlinear, triplet-linear, and triplet-nonlinear electronic states and geometries, and for isoelectronic AB systems with singlet and triplet electronic states. For these systems, A = B^-, Al^-, Ga^-, C, Si, Ge, N …

Pentacarbonyl Derivatives Of Polydentate Phosphines, Yi Zang

Masters Theses

Four phosphines (Ph₂P)₂C=CHPPh₂, (p-tol)₂PCH₂P(p-tol)₂, (o-tol)₂PCH₂P(o-tol)₂, Ph₂PCH₂P(p-tol)₂ and their pentacarbonyltungsten complexes have been prepared and studied as part of a continuous investigation of polydentate phosphines that are coordinated as monodentate ligands. The ligand, (Ph₂P)₂C=CHPPh₂, was prepared by base-catalyzed addition of Ph₂PH to Ph₂PC=CPPh₂. Reaction of this ligand with (OC)₅WNH₂Ph led to formation …

Computational Studies Of Regularities In Bond Dissociation Enthalpies And Interactions Of Acetylthiocholine With Solvent Molecules, Wencui Zheng

Masters Theses

This thesis reports the results of two different research projects. One project is an evaluation of the feasibility of applying constant bond dissociation enthalpy ratios to neutral molecules for which one atom is from group 13 or group 17 and the other atom is from group 16. The other project attempts to validate the proposal that the aromatic residues lining the acetylcholinesterase (AChE) gorge will induce entry of acetylthiocholine (ATCh) into the gorge in a manner similar to that of the neural transmitter acetylcholine.

A total of thirty AB₂ and AB molecules have been examined, where A = B, …