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Partial Ion Yield Sspectroscopy Around The Cl 2p And C 1s Ionization Thresholds In Cf3cl, D. Ceolin, Maria Novella Piancastelli, Wayne C. Stolte, Dennis W. Lindle

Chemistry and Biochemistry Faculty Research

We present a partial ion yield experiment on freon 13, CF₃Cl, excited in the vicinity of the C 1s and Cl 2p ionization thresholds. We have collected a large amount of cationic fragments and a few anionic fragments at both edges. We have observed a strong intensity dependence of Rydberg transitions with ion fragment size for the CF_nCl⁺ and CF_n⁺/F⁺ (n=0–3) series at both the Cl 2p and C 1s ionization edges. Selectivity in the fragmentation processes involving the C–Cl and C–F bonds are highlighted by the intensities of the C …

Yttrium And Hydrogen Superstructure And Correlation Of Lattice Expansion And Proton Conductivity In The Bazr0.9y0.1o2.95 Proton Conductor, A. Braun, A. Ovalle, V. Pomjakushin, A. Cervellino, S. Erat, Wayne C. Stolte, T. Graule

Chemistry and Biochemistry Faculty Research

Bragg reflections in Y-resonant x-ray diffractograms of BaZr_0.9Y_0.1O_2.95 (BZY10) reveal that Y is organized in a superstructure. Comparison with neutron diffraction superstructure reflections in protonated/deuterated BZY10 suggests that both superstructures are linked, and that protons move in the landscape imposed by the Y. The thermal lattice expansion decreases abruptly for protonated BZY10 at T≥648±20 K, coinciding with the onset of lateral proton diffusion and suggesting a correlation of structural changes and proton conductivity. The chemical shift in the Y L₁-shell x-ray absorption spectra reveals a reduction from Y³⁺ toward Y²⁺ upon …

Synthesis And Characterization Of Tetraoxime Ligand, Bis-[(2e,3e,2´E)-3,3´-(1,2-Phenylene-Dinitrilo)Dibutan-2-One Dioxime] And Its Dinuclear And Tetranuclear Copper(Ii)/Nickel(Ii) Complexes, Nevi̇n Karaböcek, Pinar Ekmekçi̇oğlu, Asligül Küçükdumlu, Serdar Karaböcek

Turkish Journal of Chemistry

A new tetraoxime, (H_4L), was prepared in EtOH by reacting biphenyl-3,3´,4,4´-tetramine with butane-2,3-dione oxime. The tetraoxime ligand was characterized by elemental analyses, H-NMR and ^{13}C-NMR, IR, and mass spectral studies. Dinuclear copper(II), nickel(II) and tetranuclear copper(II) complexes of tetraoxime ligand were prepared and characterized by elemental analyses, magnetic moments, IR, and mass spectral studies. In the dinuclear metal complexes, metal:ligand ratio was found as 2:1. Elemental analyses and stoichiometric and spectroscopic data of the metal complexes indicated that the metal ions were coordinated to the nitrogen atoms of oxime groups (C=N). In addition, total energy and heat formation for ligand …

One-Pot Synthesis Of Amidoalkyl Naphthols Using Nahso_4.Sio_2 As An Efficient And Recyclable Heterogeneous Catalyst, Hamid Reza Shaterian, Hossein Yarahmadi, Majid Ghashang

Turkish Journal of Chemistry

An efficient synthesis of amidoalkyl naphthols using silica supported sodium hydrogen sulphate as heterogeneous catalyst under a thermal solvent-free green procedure is described. This simple protocol offer advantages such as shorter reaction times, simple work-up, excellent yield, and recovery and reusability of the catalyst.

Exploring The Ph Dependence Of Viologen Reduction By Alpha-Carbon Radicals Derived From Hcy And Cys, Dong Wang, William E. Crowe, Robert M. Strongin, Martha Sibrian-Vazquez

Chemistry Faculty Publications and Presentations

The colorimetric reaction of homocysteine (HCy) with a series of viologen salts suggests a linear correlation between the mid-point reduction potential of Hcy-derived α-carbon radicals and pH.

Structural Basis For Binding Specificity Between Subclasses Of Modular Polyketide Synthase Docking Domains, Tonia Buchholz, Todd W. Geders, Frank E. Bartley Iii, Kevin A. Reynolds, Janet L. Smith, David H. Sherman

Chemistry Faculty Publications and Presentations

Bacterial type I polyketide synthases (PKSs) assemble structurally diverse natural products of significant clinical value from simple metabolic building blocks. The synthesis of these compounds occurs in a processive fashion along a large multiprotein complex. Transfer of the acyl intermediate across interpolypeptide junctions is mediated, at least in large part, by N- and C-terminal docking domains. We report here a comprehensive analysis of the binding affinity and selectivity for the complete set of discrete docking domain pairs in the pikromycin and erythromycin PKS systems. Despite disconnection from their parent module, each cognate pair of docking domains retained exquisite binding selectivity. …

Hydroxyl Radical Is Produced Via The Fenton Reaction In Submitochondrial Particles Under Oxidative Stress: Implications For Diseases Associated With Iron Accumulation, Carin Thomas, Melissa M. Mackey, Amy A. Diaz, David P. Cox

All Faculty Scholarship for the College of the Sciences

Mitochondrial dysfunction and reactive oxygen species (ROS) are often implicated in diseases involving oxidative stress and elevated iron. As mitochondria produce ATP by oxidative phosphorylation, ROS by-products are generated from the electron transport chain. Although superoxide and hydrogen peroxide have been thoroughly investigated, little evidence documents hydroxyl radical (HO•) production in mitochondria. In order to determine whether HO• is generated under oxidative stress conditions by a Fenton-type mechanism, bovine heart submitochondrial particles were examined for HO• in the presence and absence of iron ligands, antioxidant enzymes and HO• scavengers. HO• was measured as 2,3- and 2,5-dihydroxybenzoic acid (DHBA), using HPLC …

Upgrade Of A Raman Spectrometer With Modern Computer Control And Data Acquisition For Studies Of Hydrogen Bonding In Pyrimidine, Austin Howard

Honors Theses

The restoration of a Cold War era high resolution Raman spectrometer to working order as well as its control and data acquisition upgrade using a Labview program authored for this purpose are discussed. The restored Raman spectrometer was used in an investigation of intermolecular interactions involving pyrimidine. Following in this manuscript are three chapters. The first chapter is a brief description of the history and theory of Raman spectroscopy as well as some details of the instrumentation used in Raman spectroscopy. The second chapter contains technical details of the restoration and upgrade of the high resolution Raman spectrometer. The third …

Structural Studies Of Biopolymers Using Computer Simulations, Optical And Magnetic Spectroscopy, Subhasish Chatterjee

Dissertations, Theses, and Capstone Projects

Biopolymers are essential components of numerous natural and synthetic macromolecular assemblies. In the present study, the structural properties of biopolymers ranging from fungal melanins to synthetic nucleic acids were investigated using spectroscopic methods and theoretical modeling. (1) Computational modeling and molecular dynamics simulations were used to study the structural properties of a short single-stranded (ss) DNA. The dependence of the conformational stability and flexibility of the ssDNA on the thermodynamic conditions of the system was demonstrated. (2) Time-resolved fluorescence spectroscopy involving an organic donor-quencher pair was utilized to study the conformational properties of Y-shaped DNA. Results highlighted the different distances …

Three-Component Process For The Synthesis Of Some Pyrrole Derivatives Under Microwave Irradiation, Farhad Hatamjafari, Nasser Montazeri

Turkish Journal of Chemistry

We report a short and efficient 3-component reaction for synthesis of a series of [1,2-b]pyrrole derivatives from ninhydrin, alkyl propiolates, and simple primary amines under solvent free and microwave irradiation. This method provides a new route to produce pyrrole derivatives in good to excellent yields.

Pattern Recognition Integrated Sensing Methodologies (Prisms) In Pharmaceutical Process Validation, Remote Sensing And Astrobiology, Thaddaeus S. Hannel

University of Kentucky Doctoral Dissertations

Modern analytical instrumentation is capable of creating enormous and complex volumes of data. Analysis of large data volumes are complicated by lengthy analysis time and high computational demand. Incorporating real-time analysis methods that are computationally efficient are desirable for modern analytical methods to be fully utilized. The use of modern instrumentation in on-line pharmaceutical process validation, remote sensing, and astrobiology applications requires real-time analysis methods that are computationally efficient.

Integrated sensing and processing (ISP) is a method for minimizing the data burden and sensing time of a system. ISP is accomplished through implementation of chemometric calculations in the physics of …

A Lab To Stemulate Undergraduate Students Into Science, Technology, Engineering And Mathematics Majors, Nicole Lynn Speelman

Browse all Theses and Dissertations

The central focus is the development and implementation of a research/lab module for first year chemistry courses. Electrochemical techniques are utilized to study oxidation and reduction reactions of neurotransmitters with a poly(2,2'-Bithiophene) modified electrode. The goal is to excite students about chemistry and encourage them to continue studies in Science, Technology, Engineering, and Mathematics (STEM) during their undergraduate education. The lab module was created for Project REEL (Research Experiences to Enhance Learning) and will be illustrated with results typically obtained by students. The experiment is inquiry-based, which includes challenging questions students have to do collaboration and research to answer, as …

Design, Synthesis, And Characterization Of Novel Hydrophilic Fluorene-Based Derivatives For Bioimaging Applications, Dao Nguyen

Electronic Theses and Dissertations

In this work, hydrophilic fluorene-based derivatives that contain ethylene oxide substituents, have been synthesized and characterized for potential use as new fluorophores for bioimaging applications and for fluorescence sensing of heavy metals. Symmetrical and unsymmetrical fluorene derivatives based on structural types of acceptor-pi-acceptor, acceptor-pi-donor, and donor-pi-donor were characterized by TGA, UV-vis absorption, fluorescence emission, lifetime, anisotropy, and two-photon absorption (2PA) cross section. They were found to possess high thermal stability, high photostability, high fluorescence quantum yields, and generally large two-photon absorption cross sections, making them quite suitable for new probes in single-photon absorption and two-photon absorption fluorescence microscopy imaging. Novel …

Electrospray And Photoionization Mass Spectrometry For The Characterization Of Organic Matter In Natural Waters: A Qualitative Assessment, William C. Hockaday, Jeremiah M. Pucell, Alan G. Marshall, Jeffery A. Baldock, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Fourier-transform ion cyclotron resonance mass spectrometry (MS) has demonstrated potential to revolutionize the fields of limnology and chemical oceanography by identifying the individual molecular components of organic matter in natural waters. The use of MS for this purpose is made possible by the electrospray technique which successfully ionizes polar, nonvolatile organic molecules. Another recently developed ion source, atmospheric pressure photoionization (APPI), extends MS capabilities to less polar molecules. This article presents early results on the application of APPI MS to natural organic matter. We compare APPI MS and electrospray MS data for dissolved organic matter from Lake Drummond (Virginia, USA). …

On-Line Laser Desorption/Ionization Mass Spectrometry, Damien A. Narcisse

LSU Doctoral Dissertations

Interfaces for on-line laser desorption/ionization mass spectrometry are presented in this dissertation. An on line laser desorption interface allows samples to be introduced directly into the mass spectrometer for high-throughput applications. For this research, a linear time of flight mass spectrometer was constructed with an ionization source designed to accept various laser desorption interfaces. A ball inlet interface was used for continuous analyte deposition at atmospheric pressure and vacuum ionization. A solvent-based cleaning system and a separate capillary for MALDI matrix delivery was utilized for continuous on line sampling with the ball inlet interface. Microfluidic devices were brought into contact …

Microwave Assisted Solid-Supported Organic Synthesis: A Novel Methodology To Obtain 2,3-Disubstituted-1,4-Naphthoquinones, Israel Garcia-Martinez

Open Access Theses & Dissertations

This research focuses on the combinatorial solid phase organic synthesis (SPOS) of different bioactive compounds utilizing transition metal mediated reactions via microwave assisted organic synthesis (MAOS).

A microwave-assisted solid-supported Dötz benzannulation of chromium Fischer carbene complexes with various alkynes has been reported. The oxidative cleavage of the resulting resin-bound 1,4-naphthols affords 2,3-disubstituted-1,4-naphthoquinone derivatives in good to moderate yields with high purities. We demonstrated that solid phase organic synthesis of naphthoquinones via conventional heating is limited due to their long reaction times and high temperatures. The products decompose leading to low yields and purities.2 Microwave assisted synthesis of these naphthoquinones will …

Pressure Induced Phase Transformation Of Sno2: An Ab Initio Constant Pressure Study, Daniel Tesfai Yehdego

Open Access Theses & Dissertations

The behavior of SnO2 under rapid hydrostatic pressures is studied using constant-pressure ab initio simulations. The rutile-type SnO2 gradually transforms into the CaCl2-type structure at 15 GPa. At a pressure of about 20 GPa, a phase transformation into a cubic fluorite-type structure is observed. The orthorhombic Pnma cotunnite-structured phase is observed above 150 GPa. The mechanisms of these phase transformations at the atomistic level are discussed.

An Improved Synthesis Of The Hdac Inhibitor Trichostatin A, Joseph Colombo

Master's Theses and Doctoral Dissertations

Histone deacetylase inhibitors (HDIs) have found a wide variety of medicinal uses and are most noted for their specific apoptotic action towards cancer cells. Several hydroxamate HDIs have since been moved on to phase 1 and 2 clinical drug trials, with one having already been approved for treatment of advanced cutaneous T-cell lymphoma. Trichostatin A is one of the most potent known naturally-occurring inhibitors of histone deacetylase. Unfortunately for researchers, the syntheses that have been reported are both long and difficult, which leads to a low overall yield and therefore to a prohibitively expensive product, limiting its medicinal potential. This …

Development Of A Headspace Solid-Phase Microextraction (Hs-Spme) Procedure For The Determination Of Short-Chain Fatty Acids (Scfas) In Activated Sludge By Gc-Fid, Shiyan Cheng

Master's Theses and Doctoral Dissertations

The process of wastewater treatment includes the removal of inorganic solids such as sand and gravel as well as organic materials, phosphorus, and nitrogen. Activated sludge, containing a variety of living organisms, is added into the wastewater treatment system. Short-chain fatty acids (SCFAs), an energy source of the bioorganisms, are produced during activated sludge digestion, and play a significant role in phosphorus and nitrogen removal as well as the removal of organic materials during the process of wastewater treatment. Extensive research has been carried out recently in search of optimized conditions to increase the level of fatty acids in the …

Salsola Kali (Tumbleweed): A Possible Biomonitoring Device For The Detection Of Airborne Heavy Metals, Tenoch Benitez

Open Access Theses & Dissertations

Vehicular congestion generates particulate matter and contaminants such as lead, cadmium, copper, chromium, nickel, and zinc which have been detected in the U.S.-Mexico border region. To overcome the inconvenience of expensive sampling techniques, scientists started to assess air quality by using bioindicator plants, a technique called biomonitoring. Biomonitoring is an inexpensive and environmentally friendly approach to determine inorganic contaminants at trace levels. The purpose of this project was to determine the effectiveness of tumbleweed (Salsola kali) plants, sprayed with chelating agents, as a passive monitoring device to determine the possible presence of heavy metals in the ambient air around international …

Computational Modeling Studies Of The Structures And Properties Of Organotin(Iv) And Stannyl-Thioether Systems With Comparisons To X-Ray Crystallography, Michelle R. Stem Joseph

Open Access Theses & Dissertations

Controlling the toxic effects of organotin(IV) compounds involves engineering the structure of the molecules to optimize their properties. Molecular engineering, coupled with improved capabilities to generate reliable computational optimization models (COMs), will enable researchers to have greater success at harnessing the highly specific cytotoxicity of organotins. For example, as the thio_n ligand phenyl groups were replaced with Cl atoms, the S-Sn intramolecularity was strengthened, the bond distance decreased, and the stannyl tetrahedral structure was deformed from its triphenyl conformation. With each substitution, conformation deformations lowered the damaging bioactivity levels of thio_n. Bonding various ligands to organotin(IV) compounds …

Cationic Exchange Reactions Involving Dilithium Phthalocyanine, Morgan M. Hart

Browse all Theses and Dissertations

Dilithium phthalocyanine (Li₂Pc) consists of an aromatic macrocycle possessing a doubly negative charge and two Li⁺ counterions. One Li⁺ ion is easily displaceable while the other remains coordinated to the phthalocyanine ring. The displaceable Li⁺ cation can be exchanged with other cations, such as a singly charged tetra-alkyl ammonium cation, by using several variations of a general procedure. It has been demonstrated that tetraalkylammonium lithium phthalocyanines (TAA-LiPcs) can be successfully and reproducibly synthesized with yields ranging from 54.5% up to 64.3%. All TAA-LiPcs demonstrated poor solubilities from approximately <0.2 mg/mL to 5 mg/ml in the solvents tested (with the exception of tetrapropylammonium lithium phthalocyanine and tetrahexylammonium lithium phthalocyanine). All of the TAA-LiPcs synthesized were dark-purple in color, with the exception of tetraheptylammonium lithium phthalocyanine and tetraoctylammonium lithium phthalocyanine. These two compounds were dark - blue in color. Melting points varied greatly from >370.4°C to 157.9°C and depended greatly upon …

Quantum Chemical Investigations Of Nucleophilic Aromatic Substitution Reactions And Acid Dissociations Of Aliphatic Carboxylic Acids, David Henry Schory

Browse all Theses and Dissertations

Quantum chemical analysis was used to examine nucleophilic aromatic substitution reactions of fluorinated benzophenones, diphenyl sulfones, and triphenylphosphine oxides. Some experimental results for these compounds were contrary to conventional wisdom, which holds that calculated atomic charges for the aromatic sites and ¹³C-NMR and ¹⁹F-NMR chemical shifts should allow prediction of the preferred sites for aromatic substitution. Density functional theory (B3LYP/6-31+G*//RM1) and semi-empirical (RM1) quantum chemical calculations were employed to study the intermediates in the reaction pathways in order to identify the preferred paths for aromatic substitution. In most cases studied para substitution pathways had the lower energy intermediates …

Lithiation Reactions Of 3-(4-Chlorophenyl)Sydnone And 3-(4-Methylphenyl)Sydnone, Nigel Ngonidzashe Chitiyo

Browse all Theses and Dissertations

Ortho-iodophenyl sydnones are key intermediates in Sonogashira coupling reactions and the resulting ortho alkynyl sydnones are useful precursors to functionalized sydnonquinolines. In this work, three synthetic routes leading to the synthesis of these versatile intermediates were explored.

Lithiation reactions of 3-(4-chlorophenyl) sydnone and 3-(4-methylphenyl) sydnone followed by trapping with iodine electrophiles yielded the expected disubstituted species 3-(4-chloro-2-iodophenyl)-4-iodosydnone and 3-(4-methyl-2-iodophenyl)-4-iodosydnone in yields ranging from 14% to 75%. Subsequent reduction with sodium sulfite removed the iodine at the C-4 position in both species yielding the ortho iodophenyl sydnones in 80% and 85% yield, respectively.

A surprising result was the discovery that careful …

First-Principles Study Of Methane Dehydrogenation On A Bimetallic Cu/N(111) Surface, Wei An, Xiao Cheng Zeng, C. Heath Turner

Xiao Cheng Zeng Publications

We present density-functional theory calculations of the dehydrogenation of methane and CH_x (x = 1 – 3) on a Cu/Ni(111) surface, where Cu atoms are substituted on the Ni surface at a coverage of 1/4 monolayer.

On The Phase Diagram Of Water With Density Functional Theory Potentials: The Melting Temperature Of Ice /H With The Perdew–Burke–Ernzerhof And Becke–Lee–Yang–Parr Functionals, Soohaeng Yoo, Xiao Cheng Zeng, Sotiris C. Xantheas

Xiao Cheng Zeng Publications

The melting temperature (T_m) of ice I_h was determined from constant enthalpy and pressure (NPH) Born–Oppenheimer molecular dynamics simulations to be 417±3 K for the Perdew–Burke– Ernzerhof and 411±4 K for the Becke–Lee–Yang–Parr density functionals using a coexisting ice (I_h)-liquid phase at constant pressures of P=2500 and 10 000 bar and a density p=1 g/cm³, respectively.

Androgen-Stimulated Udp-Glucose Dehydrogenase Expression Limits Prostate Androgen Availability Without Impacting Hyaluronan Levels, Qin Wei, Robert Galbenus, Ashraf Raza, Ronald Cerny, Melanie A. Simpson

Ronald Cerny Publications

UDP-glucose dehydrogenase (UGDH) oxidizes UDP-glucose to UDP-glucuronate, an essential precursor for production of hyaluronan (HA), proteoglycans, and xenobiotic glucuronides. High levels of HA turnover in prostate cancer are correlated with aggressive progression. UGDH expression is high in the normal prostate even though HA accumulation is virtually undetectable. Thus, its normal role in the prostate may be to provide precursors for glucuronosyltransferase enzymes, which inactivate and solubilize androgens by glucuronidation. In this report, we quantified androgen dependence of UGDH, glucuronosyltransferase, and HA synthase expression. Androgen dependent and independent human prostate cancer cell lines were used to test the effects of UGDH …

A New Peroxide Fragmentation: Efficient Chemical Generation Of 1O2 In Organic Media, Patrick Dussault, Prasanta Ghorai

Department of Chemistry: Faculty Publications

Monoactivated derivatives of 1,1-dihydroperoxides undergo an unprecedented base-promoted fragmentation to efficiently generate singlet oxygen (¹O₂) in anhydrous organic solvents.

A Multi-Step Nmr Screen For The Identification And Evaluation Of Chemical Leads For Drug Discovery, Kelly A. Mercier, Matthew D. Shortridge, Robert Powers

Department of Chemistry: Faculty Publications

A multi-step NMR based screening assay is described for identifying and evaluating chemical leads for their ability to bind a target protein. The multi-step NMR assay provides structure-related information while being an integral part of a structure based drug discovery and design program. The fundamental principle of the multi-step NMR assay is to combine distinct 1D and 2D NMR techniques, in such a manner, that the inherent strengths and weakness associated with each technique is complementary to each other in the screen. By taking advantage of the combined strengths of 1D and 2D NMR experiments, it is possible to minimize …

Energy Gradients In Combined Fragment Molecular Orbital And Polarizable Continuum Model (Fmo/Pcm) Calculation, Hui Li, Dmitri G. Federov, Takeshi Nagata, Kazuo Kitaura, Jan H. Jensen, Mark S. Gordon

Hui Li Publications

The analytic energy gradients for the combined fragment molecular orbital and polarizable continuum model (FMO/PCM) method are derived and implemented. Applications of FMO/PCM geometry optimization to polyalanine show that the structures obtained with the FMO/PCM method are very close to those obtained with the corresponding full ab initio PCM methods. FMO/PCM (RHF/6-31G* level) is used to optimize the solution structure of the 304-atom Trp-cage miniprotein and the result is in agreement with NMR experiments. The key factors determining the relative stability of the a-helix, b-turn and the extended form in solution are elucidated for polyalanine.