Chemistry Commons^™

Synthesis And Characterization Of [Vo(O2)H2edta] And Investigation Of The Reaction Between [Vohedta]-1 And Hydrogen Peroxide As A Model Catalyst For Haloperoxidases, Tinga C. O. Fon Mr.

Electronic Theses and Dissertations

Vanadium haloperoxidases (VHPOs) are enzymes that catalyse the oxidation of halide ions to hypohalous acids by hydrogen peroxide. There are many unanswered questions on the mechanism by which the oxidation reaction occurs. In this work, is reported the synthesis of [VO(O₂)H₂EDTA], studies of the effect of acid concentration on the decomposition of [VO(O₂)HEDTA]^-2, and mechanistic studies of the rate law. The decomposition reaction was found to be first order with respect to acid concentration and also [VO(O₂)HEDTA]^-2 concentration. The reaction of [VOHEDTA]^-1 and hydrogen peroxide progressed via a …

Synthesis And Characterization Of Novel Platinum(Ii) And Platinum(Iv) Complexes Containing 4,4′--Disubstituted--2,2′--Bipyridine Ligands For The Treatment Of Cancer, Van Vo

UNLV Theses, Dissertations, Professional Papers, and Capstones

Three series of platinum(II) and platinum(IV) complexes containing 4,4′-disubstituted-2,2′-bipyridine ligands have been synthesized and characterized by 1H NMR, 13C NMR spectroscopy, elemental analysis, mass spectroscopy, and differential scanning calorimetry measurements. The MTS cell proliferation assay was used to examine the in vitro anti-proliferative activities of these complexes in various human breast, lung, and prostate cancer cells. The cell's response to the complexes varies between different cell lines; however, the low EC₅₀ values determined from the MTS data indicate that several of the complexes are much more potent than cisplatin.

Flow cytometric analysis of selected compounds revealed induction of apoptosis …

Speciation Behavior Of Americium Higher Oxidation States For The Separation Of Americium From Curium, Catherine Lynn Riddle

UNLV Theses, Dissertations, Professional Papers, and Capstones

Several countries are currently expanding the use of nuclear energy as a method for the safe generation of carbon free energy and a number are evaluating starting up a nuclear power program. Closed fuel cycle technologies may be key to waste reduction and a sustainable nuclear energy future and to support the development of more efficient fuel cycles, the investigation of the chemical properties of key actinides is at the forefront of separations research. In this work the characterization of higher oxidation states of americium (Am) has been performed using spectroscopic methods. Americium in the formal oxidation state of Am(V) …

Electrochemical And Microfabrication Strategies For Remotely Operated Heavy Metal Sensor Networks For Water Analysis : The Dual Challenges Of Calibration-Less Measurement And Sample Pretreatment., Mohamed M. Marei

Electronic Theses and Dissertations

Current heavy metal monitoring in water utilizes sophisticated instrumental methods at centralized laboratories. For many applications, a preferable approach is the deployment of remote sensor networks. To this end, electrochemical methods in conjunction with microfabricated sensors potentially offer the required sensitivity and practical advantages including inexpensive sensors, reduced need for manual operation, reduced energy requirements, and also takes advantage of existing technologies such as communications networks for real-time data acquisition. The remote sensor platform developed herein consists of a photo-lithographically patterned gold electrode on SiO2 substrate within a custom stopped-flow thin-layer cell (TLC). Metal concentrations were evaluated by anodic stripping …

Mechanistic Insights And Functionalization Of Alkynes In Homogeneous Gold Catalysis., Manish Kumar

Electronic Theses and Dissertations

The focus of my dissertation work was to study the basic mechanistic insights of gold-catalyzed reactions. Although the various mechanistic pathways of gold catalysis are better understood nowadays, numerous questions still remain unanswered concerning the nature of deactivation of the catalyst's active species, high resistance towards protodeauration, and how we can solve these problems to improve the efficiency of gold catalysis. To address these challenges in gold catalysis we conducted first a detailed experimental study to understand the mechanism of deactivation of gold active species. Based on the combination of experimental data, we proposed that gold disproportionation is preferred as …

Electron Transfer In Pnicogen Bond, Liangyu Guan

Masters Theses

Abstract is available for download as a separate file.

Persistent Hepatic Structural Alterations Following Nanoceria Vascular Infusion In The Rat, Michael T. Tseng, Qiang Fu, Khoua Lor, G. Rafael Fernandez-Botran, Zhong-Bin Deng, Uschi M. Graham, D. Allan Butterfield, Eric A. Grulke, Robert A. Yokel

Chemistry Faculty Publications

Understanding the long-term effects and possible toxicity of nanoceria, a widely utilized commercial metal oxide, is of particular importance as it is poised for development as a therapeutic agent based on its autocatalytic redox behavior. We show here evidence of acute and subacute adverse hepatic responses, after a single infusion of an aqueous dispersion of 85 mg/kg, 30 nm nanoceria into Sprague Dawley rats. Light and electron microscopic evidence of avid uptake of nanoceria by Kupffer cells was detected as early as 1 hr after infusion. Biopersistent nanoceria stimulated cluster of differentiation 3⁺ lymphocyte proliferation that intermingled with nanoceria-containing …

Detecting Non-Seismic Precursor Earthquake Signals Using Tree Antennas, Jaqueline O. Lopez

STAR Program Research Presentations

Forecasting earthquakes has yet to be achieved. However, there are numerous non-seismic precursor signals, which become detectable weeks to days before major events – for instance changes in Earth’s electrical surface potential. These changes are due to the arrival of positive electronic charge carriers, known as positive holes, stress-activated deep in the Earth’s crust, in the hypocenter of the future earthquake. Trees can be used as antennas for detecting the surface potential changes due to these mobile charges. This configuration allows for the detection of diurnal variations of the ground potential. Although we only had 105 days worth of data, …

Cnt Welding Through Ar Bombardment Using Airebo Potential And Optimization Of An Extensionded Aireo Potential For F Atom To Simulate Hydrofluorocarbons, Mustafa Kucukkal

All Dissertations

ABSTRACT Molecular Dynamics (MD) is an effective method to study diverse systems to gain atomistic level details from the trajectories of particles in the system. MD require a potential which describes the interaction of the particles within the system, which is then used to solve Newton's equation of motion to obtain the trajectories of the particles. For an accurate simulation of a system, an appropriate potential should be used for the MD simulations. The Adaptive Interactive Reactive Empirical Bond Order (AIREBO) potential is a promising potential for MD simulations of systems involving bond breakage or formation [1, 2]. The AIREBO …

Passivation And Functionalization Of Conjugated Polymer Nanoparticles With Head Group Modified Phospholipids And Proteins, Prakash Kandel

All Dissertations

Conjugated polymer nanoparticles (CPNs) possess important characteristics such as high fluorescence brightness, reasonable photostability, and non-toxicity. These properties allow the use of CPNs in fluorescence based cellular and biological applications including cellular labeling, imaging, biosensing, and single particle tracking. To realize the broad applications of CPNs, it is required that CPNs possess functionality to conjugate a recognition moiety and maintain colloidal stability in biological media. In the following Dissertation, we have prepared functionalized CPNs by surface passivation with head group- functionalized poly (ethylene glycol) lipids and proteins. We studied the colloidal stability of CPNs in biological media and investigated their …

Modified-Electrodes For Redox-Magnetohydrodynamic (Mhd) Pumping For Microfluidic Applications, Christena Kayl Nash

Graduate Theses and Dissertations

A new microfluidic pumping and stirring technique was demonstrated for lab-on-a-chip applications. Microfluidics was accomplished via redox-MHD, which takes advantage of a body force (F_B) that is generated when there is a net movement of ions in solution (j) in the presence of a perpendicular magnetic field (B), according to the equation F_B = j×B. In this work the movement of ions in solution was generated using electrodes modified with the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) rather than a redox species in solution, which can interfere with analyte detection and with biological species. …

Development And Application Of Explicitly Correlated Wave Function Based Methods For The Investigation Of Optical Properties Of Semiconductor Nanomaterials, Jennifer Mary Elward

Dissertations - ALL

Semiconductor nanoparticles, or quantum dots (QDs), are well known to have very unique optical and electronic properties. These properties can be controlled and tailored as a function of several influential factors, including but not limited to the particle size and shape, effect of composition and heterojunction as well as the effect of ligand on the particle surface. This customizable nature leads to extensive experimental and theoretical research on the capabilities of these quantum dots for many application purposes.

However, in order to be able to understand and thus further the development of these materials, one must first understand the fundamental …

Theoretical Investigation Of The Quantum-Confined Stark Effect, Christopher Jon Blanton

Dissertations - ALL

The two main objectives of this dissertation are the systematic development of explicitly correlated electron-hole wave function based methods and the application of these methods to chemical systems with an

emphasis on nanoparticles.

The understanding of the basic physics of excited electronic states is an important consideration when developing new methods and applications. In this dissertation, excited electronic states were studied using the electron-hole quasiparticle representation. Theoretical treatment of electronic excitation in large quantum dots and nanoparticles is challenging because of the large number of electrons in the system. The quasiparticle representation provides an alternative representation that can partially alleviate …

Structural Studies Of Bile Salt Aggregation By Nuclear Magnetic Resonance Spectroscopy And Mass Spectrometry, Nicholas Doyle

Master’s Theses

Bile salts are biomolecules that are produced in the liver and are responsible for a range of functions in the process of digestion, primarily the emulsification of dietary fat and fat-soluble vitamins. Despite their importance in biological chemistry, the structure and dynamics of bile salt aggregation are not well understood. The efforts described herein attempt to enhance the understanding of cholate aggregation numbers (AN), critical micelle concentration (CMC), micellar structure(s), and interactions with a binaphthyl probe molecule. Cholate is the most common bile salt in mammals and is, therefore, a decent model for describing bile salt aggregation. CMC determination is …

High-Performance Polymer Monoliths For Capillary Liquid Chromatography, Pankaj Aggarwal

Theses and Dissertations

This dissertation focuses on improving the chromatographic efficiency of polymeric organic monoliths by characterizing and optimizing the bed morphology. In-situ characterization techniques such as capillary flow porometry (CFP), 3-dimensional scanning electron microscopy (3D SEM) and conductivity measurements were developed and implemented to quantitatively characterize the morphology of poly(ethylene glycol) diacrylate (PEGDA) monoliths. The CFP measurements for monoliths prepared by the same procedure in capillaries with different diameters (i.e., 75, 150, and 250 μm) clearly showed a change in average through-pore size with capillary diameter, thus, certifying the need for in-situ measurement techniques. Serial sectioning and imaging of PEGDA monoliths using …

Fde-Vdw: A Van Der Waals Inclusive Subsystem Density-Functional Theory, Ruslan Kevorkyants, Hendrik Eshuis, Michele Pavanello

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

We present a formally exact van der Waals inclusive electronic structure theory, called FDE-vdW, based on the Frozen Density Embedding formulation of subsystem Density-Functional Theory. In subsystem DFT, the energy functional is composed of subsystem additive and non-additive terms. We show that an appropriate definition of the long-range correlation energy is given by the value of the non-additive correlation functional. This functional is evaluated using the fluctuation-dissipation theorem aided by a formally exact decomposition of the response functions into subsystem contributions. FDE-vdW is derived in detail and several approximate schemes are proposed, which lead to practical implementations of the method. …

Enhanced Charge Photogeneration Promoted By Crystallinity In Small-Molecule Donor-Acceptor Bulk Heterojunctions, Keshab Paudel, Brian Johnson, Mattson Thieme, Michael M. Haley, Marcia M. Payne, John E. Anthony, Oksana Ostroverkhova

Chemistry Faculty Publications

We examined sub-nanosecond time-scale charge carrier dynamics in crystalline films of a functionalized anthradithiophene (ADT) donor (D) with three different acceptor (A) molecules. A four-fold enhancement in ultrafast charge carrier separation efficiency was observed in D/A blends with a fullerene acceptor added at 7–10 wt. % concentrations, whereas a gradual decrease in peak photocurrent amplitude with acceptor concentration was observed with functionalized pentacene and indenofluorene acceptors. The results were directly correlated with the ADT-tri(ethylsilyl)ethynyl-F donor crystallinity. In the best-performing blends, the presence of crystalline acceptor domains was also established.

Design And Synthesis Of Chelating Compounds And Solid-Supported Chelators For Metal Depleted Solutions, Surendra Dawadi

Dissertations

Metals are essential to life, yet they can be toxic for biological systems when present in excessive amounts. The major source of metal overload in humans is diet; and in some cases, intravenous feeding. Thus the removal of toxic metal ions from contaminated clinical products such as total parenteral nutrition (TPN) solutions, and drinking and waste water is extremely important. The use of chelating resins, which are polymeric solids containing covalently immobilized chelating compounds, for the selective removal of metal ions from contaminated solutions has been conceptualized long ago. Herein, the design and synthesis of metal specific chelating compounds and …

Peptide Bond Formation Via Glycine Condensation In The Gas Phase, Eric Van Dornshuld, Robert A. Vergenz, Gregory S. Tschumper

Chemistry Faculty Research & Creative Works

Four unique gas phase mechanisms for peptide bond formation between two glycine molecules have been mapped out with quantum mechanical electronic structure methods. Both concerted and stepwise mechanisms, each leading to a cis and trans glycylglycine product (four mechanisms total), were examined with the B3LYP and MP2 methods and Gaussian atomic orbital basis sets as large as aug-cc-pVTZ. Electronic energies of the stationary points along the reaction pathways were also computed with explicitly correlated MP2-F12 and CCSD(T)-F12 methods. The CCSD(T)-F12 computations indicate that the electronic barriers to peptide bond formation are similar for all four mechanisms (ca. 32-39 kcal mol-1 …

Light Switchable Optical Materials From Azobenzene Crosslinked Poly (N-Isopropylacrylamide)-Based Microgels, Qiang Matthew Zhang, Xue Li, Molla R. Islam, Menglian Wei, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

4,4′-Di(acrylamido)-azobenzene was used as a crosslinker in poly(N-isopropylacrylamide)-based microgels. The microgels were subsequently used to fabricate microgel-based optical materials (etalons), which exhibited optical properties that were switchable upon exposure to UV irradiation. We also show that the extent of the response depended on the UV exposure time. These materials could find applications for controlled/triggered drug delivery, as well as in various optical applications.

Poly (N-Isopropylacrylamide) Microgel-Based Thin Film Actuators For Humidity Sensing, Molla R. Islam, Michael J. Serpe

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

In this submission we fabricated a humidity-responsive polymer-based actuator by layering negatively charged poly(N-isopropylacrylamide)-co-acrylic acid microgels and positively charged poly(diallyldimethyl ammonium chloride) on top of a flexible plastic substrate. We show that the extent of the actuation (bending) was dependent on the atmospheric humidity. This property was used to detect atmospheric humidity by hanging weights from the actuator, which were rested on the pan of a top loading balance. This was done in such a way that the amount of the mass resting on the balance depended on the extent of actuator bending, which could then be related to humidity. …

Chemistry And Thermochemistry Of Selected Fatty Acids Using Correlation Gas Chromatography, Joe A. Wilson

Dissertations

Correlation gas chromatography (c-GC) is a special application of the gas chromatography technique and is used for the evaluation of both vaporization enthalpy and vapor pressures of organic compounds. Its use in measuring vaporization enthalpies has been extensively documented. This method is useful for measurements of both liquids and solids. For substances that are solids, since each analyte is dilutely adsorbed on the condensed phase of the gas chromatographic column, it is not crystalline. The vapor pressure that it exhibits behaves as an excellent model of the sub-cooled liquid as demonstrated by various thermochemical cycles. Thermochemical measurements are important to …

Nanoporous Gold Characterization, Structural Modification And Use As A Solid Support For Biomolecule Immobilization, Abeera Sharma

Dissertations

Nanoporous gold (NPG) has immense technological applications owing to a plethora of properties like large surface area to volume ratio, plasmonic properties, stable gold-thiolate bond formation and a wide range of pore sizes. The surface morphology of nanoporous gold has been altered previously by dealloying and thermal annealing to increase/decrease the pore size and change the surface area. We provide a novel electrochemical annealing technique for post dealloying modification wherein electrochemical sweep cycles in different electrolytes at positive potentials leads to a subsequent increase in pore sizes of nanoporous gold as studied using scanning electron microscopy. Tailoring the surface of …

Determination Of Thiamine In Solution By Uv-Visible Spectrophotometry: The Effect Of Interactions With Gold Nanoparticles, Michael Vincent Zielinski

Master's Theses and Doctoral Dissertations

The method presented here provides the foundation for a simple and selective qualitative determination of thiamine in solution. Gold nanoparticles in the presence of thiamine results in the formation of a secondary peak in the absorbance spectrum of the mixture. This peak can be used as an indicator of thiamine, which is useful for the qualitative analysis of solutions, and may provide an alternative to other methods for evaluating thiamine in blood and other biological systems. This method uses gold nanoparticles of a size around 20 to 30 nm and involves their selective interaction with thiamine, compared to selected amino …

Design, Synthesis And Evaluation Of Small Molecules As Inhibitors Of Plasminogen Activator Inhibitor-1, Darshani Avanthi Weerakoon

Master's Theses and Doctoral Dissertations

Plasminogen activator inhibitor type-1 (PAI-1) is a member of the serine protease inhibitor (serpin) superfamily. Excessive levels of PAI-1 inhibit urokinase-type plasminogen activator (uPA) and tissue-type plasminogen activator (tPA), which regulates fibrinolysis as well as the development of different pathological diseases like obesity, metabolic syndrome, tumor invasion and metastasis, and coronary heart disease. Currently, there is no Food and Drug Administration approval for inactivating higher levels of PAI-1. Therefore, PAI-1 is considered an attractive drug target. Due to PAI-1’s different structural conformations and multiple binding domains, development of PAI-1 inhibitors is a challenging situation. In this research study, we describe …

Optical Injection Unlocking For Cavity Ringdown Spectroscopy, Gregory A. Bostrom, Andrew L. Rice, Dean B. Atkinson

Physics Faculty Publications and Presentations

Continuous wave cavity ringdown spectroscopy requires a rapid termination of the injection of light into the cavity to initiate the decay (i.e., ringdown) event. We demonstrate a technique that accomplishes this through pulsed optical injection of a second laser into the main laser, resulting in 20-100 MHz frequency shifts in the otherwise cavity-locked main laser sufficient to create ringdown events at 3.5 kHz. Data on the frequency shift as a function of both main laser current and relative wavelength are presented, 88 well 88 a demonstration that single exponential decays are maintained in the process.

Derivative Couplings Between Tddft Excited States Obtained By Direct Differentiation In The Tamm-Dancoff Approximation, Qi Ou, Shervin Fatehi, Ethan Alguire, Yihan Shao, Joseph Subotnik

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

Working within the Tamm-Dancoff approximation, we calculate the derivative couplings between time-dependent density-functional theory excited states by assuming that the Kohn-Sham superposition of singly excited determinants represents a true electronic wavefunction. All Pulay terms are included in our derivative coupling expression. The reasonability of our approach can be established by noting that, for closely separated electronic states in the infinite basis limit, our final expres- sion agrees exactly with the Chernyak-Mukamel expression (with transition densities from response theory). Finally, we also validate our approach empirically by analyzing the behavior of the derivative couplings around the T1/T2 conical intersection of benzaldehyde.

56th Annual Rocky Mountain Conference On Magnetic Resonance

Rocky Mountain Conference on Magnetic Resonance

Final program, abstracts, and information about the 56th annual meeting of the Rocky Mountain Conference on Magnetic Resonance, co-endorsed by the Colorado Section of the American Chemical Society and the Society for Applied Spectroscopy. Held in Copper Mountain, Colorado, July 13-17, 2014.

Statistical Comparison Of Results Of Redox Titrations Using K-2 Cr-2o-7 And Kio-3 In The Undergraduate Analytical Chemistry Lab, David W. Randall, Luis K. Garibay

Faculty Publications

Reducing the quantity of hazardous substances used and hazardous waste generated by under- graduate laboratory experiments is important. However, simply replacing hazardous compounds with less hazardous reagents may not retain the pedagogical (or analytical) goal of the experiment if the chemistry does not fundamentally work. We evaluated several literature-based replacement oxidants for K2Cr2O7 (potassium dichromate) and identified KIO3 (potassium iodate) as the only che- mically viable alternative for thiosulfate standardizations, consistent with use of iodate by others. Using ANOVA analysis, two years of student results where K2Cr2O7 was used as the oxidant were compared with two years of student results …

Chiral Phosphoric Acids And Alkaline Earth Metal Phosphates Chemistry, Tao Liang

USF Tampa Graduate Theses and Dissertations

Asymmetric synthesis and catalysis is one of the leading research areas in chemistry society, for its versatility and efficiency in obtaining chiral molecules that found the vast majority in natural active compounds and synthetic drugs. Developing asymmetric catalytic methodology is at the frontier in both industrial and academic research laboratories. Enantioselective organocatalysis has emerged as a powerful synthetic tool that is complementary to metal-catalyzed transformations. The development of chiral phosphoric acid and metal phosphate as catalysts has been a breakthrough in recent years. Chiral phosphoric acids have been shown to be powerful catalysts in many organic transformations. Moreover, chiral metal …