Digital Commons Network^™

Pressure Induced Reversal Of The Volume Expansion Caused By Interstitial Nitrogen In Nd₂Fe₁₇N₃, R. Luo, William B. Yelon, Yusheng S.. Zhao, M. Ellouze, Ph. I'Héritier, G. K. Marasinghe, Peter C. Ezekwenna, R. B. Von Dreele, William Joseph James

Physics Faculty Research & Creative Works

No abstract provided.

D/H Exchange In Nitro Diastereomers, Charles A. Kingsbury

Department of Chemistry: Faculty Publications

The two diastereomers of 4-nitro-1,3-diphenylpentan-1-one behave differently in deuterium for hydrogen exchange in DMSO-d6/D2O solutions using various bases as catalyst. Reaction of the erythro diastereomer gives largely the same diastereomer upon D/H exchange (retention), i.e., exchange exceeds epimerization. Pyridine and acetonitrile as solvents lead to faster epimerization than exchange. In the threo diastereomer (DMSO-d6 solution), epimerization exceeds exchange, and the anion to some extent regains the same hydrogen originally removed by the base on the opposite face. 2-Bromo-4-nitro-1,3-diphenylbutan-1-one undergoes ring closure to the cyclopropane faster than exchange (within seconds). The cyclopropane shows faster exchange than equilibration, i.e., retention of configuration, …

Metathesis-Based Synthesis Of Jasmonate And Homojasmonate Lactones, Candidates For Extracellular Quorum Sensing Molecules In Candida Albicans, Su C. Cho, Patrick Dussault, Amber D. Lisec, Ellen C. Jensen, Kenneth W. Nickerson

Department of Chemistry: Faculty Publications

Ring-closing metathesis of jasmonate esters is shown to provide a rapid entry to jasmonate lactones. The lactones were investigated as possible quorum sensing molecules for the fungi Candida albicans. Assays demonstrated no effect on fungal morphology at concentrations up to 96 mM.

Method For The Synthesis Of Α-Oxranyl Amino Acids, David B. Berkowitz, Michelle L. Pedersen

Department of Chemistry: Faculty Publications

The present invention is related to a novel class of decar-boxylase enzyme inhibitors consisting of α-oxiranyl amino acids and derivatives thereof and a method of synthesizing Such compounds.

Pyrrolic Compounds, Michael J. Therien, Stephen Dimagno

Department of Chemistry: Faculty Publications

Novel methylpyrroles are provided, as well as processes for their preparation.

Cross-Coupling Of Organic Compounds Using Cuprous Odide, Reuben D. Rieke

Department of Chemistry: Faculty Publications

Cross-coupling or addition reactions of organic compounds, including acid halides, allylic halides, and C.B-unsaturated carbonyl containing compounds, with organozinc com pounds may be readily and Safely carried out in the presence of cuprous iodide. The use of this catalyst in the coupling reaction provides for the preparation of commercially useful products in the pharmaceutical, agrochemical and other industries.

Substituted Polythiophenes From Highly Reactive Zinc Reagents, Reuben D. Rieke

Department of Chemistry: Faculty Publications

A novel Zerovalent zinc species and an organozinc reagent are disclosed. The zerovalent zinc species is directly pro duced by reaction of a reducing agent on a zinc salt, preferably Zn(CN)₂. The organozinc reagent results from the reaction of the zerovalent zinc species and an organic compound having one or more stable anionic leaving groups. These organozinc reagents include a wide spectrum of functional groups in the organic radical, and are useful in a variety of reactions schemes.

Kurt Mislow Honorary Issue Of Chirality, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

No abstract provided.

Ab Initio And Dft Investigations Of Lithium/Hydrogen Bonded Complexes Of Trimethylamine, Dimethyl Ether And Dimethyl Sulfide, Salai Cheettu Ammal, P. Venuvanalingam

Faculty Publications

Ab initio and DFT computations have been carried out on LiF and HF complexes of a set of n-donors viz. trimethylamine, dimethyl ether and dimethyl sulfide with a 6-31++G(d,p) basis set. The effect of correlation has been included with MP2, MP4 and DFT calculations. NBO analyses of the wavefunctions have been performed to examine the intermolecular interaction at the orbital level. Calculations reveal that these donors form strong n→σ* complexes and computed binding energies of the (CH₃)₂O···HF complex agree very well with the experimental binding energies from IR spectroscopy. LiF forms stronger complexes than HF, …

Ab Initio Study Of Formazan And 3-Nitroformazan, G. Buemi, F. Zuccarello, P. Venuvanalingam, M. Ramalingam, Salai Cheettu Ammal

Faculty Publications

Formazan and 3-nitroformazan have been investigated at abinitio level (MP2/6-31G** and B3LYP/6-31G**) in all their possible conformations, for studying the various possibilities of intramolecular hydrogen bonding formation. The trans-syn-s-cis (TSSC), known also asyellowform, has been found to be the most stable conformer (at least in the gas phase) in both compounds. This particular structure is strongly stabilized by a N–H···N hydrogen bridge, which gives rise to a hexatomic chelate ring, with the possibility of a proton transfer process.This closely resembles that of malondialdehyde, previously studied, in the evolution of the …

Paramagnetic Nuclear Magnetic Resonance (Nmr) Studies On The Calcium Binding Site Of [Alpha]-Lactalbumin, Thomas Kurt Ritter

Dissertations and Theses

Paramagnetic NMR has drawn interest as a technique for extending the range of systems that can be investigated. The purpose of this study was to determine whether a combination of paramagnetic two-dimensional and relaxation techniques allows for assigning resonances corresponding to residues forming the metal binding site of proteins in which the metal is coordinated exclusively by amino acid side chains and which have been previously inaccessible to assignment.

α-Lactalbumin (LA) is a calcium binding protein with relatively broad NMR signals; this broadness has prevented complete assignment. LA has been the subject of many studies, because it can form a …

Influence Of Growth Conditions, Inversion Domains, And Atomic Hydrogen On Growth Of (0001_) Gan By Molecular Beam Epitaxy, Michelle Richards-Babb

Faculty & Staff Scholarship

Growth of GaN by rf-plasma molecular beam epitaxy leads to different surface morphologiesfor nitrogen-stable growth versus gallium-stable growth. Nitrogen-stable growth produces a granular surface morphology with many samples having a significant density of pyramidal hillocks. In contrast, gallium-stable growth results in a flat surface morphology. The hillocks were directly linked to the presence of inversion domains which originated in the nucleationlayer. Nitrogen-stable growth and growth under atomic hydrogen enhanced the growth rate of inversion domains with respect to the surrounding matrix, while growth under Ga-stable conditions resulted in a more nearly equal growth rate. Evidence is presented suggesting that hydrogen …

Disproportionation And Structural Changes Of Tetraarylethylene Donors Upon Successive Oxidation To Cation Radicals And To Dications, Rajendra Rathore, Sergey V. Lindeman, A. S. Kumar, Jay K. Kochi

Chemistry Faculty Research and Publications

The stepwise (one-electron) chemical oxidation of the tetraphenylethylene donor and its substituted analogues (D) can be carried out by electron exchange with aromatic cations or antimony(V) oxidants to selectively afford the cation radical (D^+•) initially and then the dication (D²⁺). The ready interchange of the latter establishes the facile disproportionation (i.e., 2D^+• ⇌ D²⁺ + D) that was originally examined by only transient electrochemical techniques. The successful isolations of the crystalline salts of the tetraanisylethylene cation radical (1^+•) as well as the …

Photoinduced Coupling Of Acetylenes And Quinone In The Solid State As Preorganized Donor−Acceptor Pairs, E. Bosch, S. M. Hubig, Sergey V. Lindeman, Jay K. Kochi

Chemistry Faculty Research and Publications

Crystalline electron donor−acceptor (EDA) complexes of various diarylacetylenes (DA) and dichlorobenzoquinone (DB) are isolated and structurally characterized by X-ray crystallography. Deliberate excitation of either the DB acceptor at λ_DB = 355 nm or the 1:2 [DA, 2DB] complex at λ_CT = 532 nm in the solid state leads to [2 + 2] cycloaddition and identical (isomeric) mixtures of the quinone methide products. Time-resolved (ps) diffuse reflectance spectroscopy identifies the ion-radical pair [DA^•+, DB^•-] as the reactive intermediate derived by photoinduced electron transfer in both photochemical …

The CuA Center Of A Soluble Domain From Thermus Cytochrome Ba3. An Nmr Investigation Of The Paramagnetic Protein. A Proton Nmr Study Of The Paramagnetic Active Site Of The CuA Variant Of Amicyanin, Richard C. Holz

Chemistry Faculty Research and Publications

No abstract provided.

Preparation And Structures Of Crystalline Aromatic Cation-Radical Salts. Triethyloxonium Hexachloroantimonate As A Novel (One-Electron) Oxidant, Rajendra Rathore, A. S. Kumar, Sergey V. Lindeman, Jay K. Kochi

Chemistry Faculty Research and Publications

Triethyloxonium hexachloroantimonate [Et₃O⁺SbCl₆^-] is a selective oxidant of aromatic donors (ArH), and it allows the facile preparation and isolation of crystalline paramagnetic salts [ArH^+•, SbCl₆^-] for the X-ray structure determination of various aromatic cation radicals. The mechanistic relationship between the Meerwein salt [Et₃O⁺SbCl₆^-] and the pure Lewis acid oxidant SbCl₅ is based on a prior ethyl transfer from oxygen to chlorine within the ion pair.

Dimethyl (±)-(1s*,2r*,3s*)-[3-Phenyl-1-(N-Phenylcarbamoyloxy)-2, 3-Epoxypropyl]-Phosphonate, T. Boehlow, A. De La Cruz, N. Rath, C. Spilling

Chemistry & Biochemistry Faculty Works

The crystal structure of the racemic title compound, C18H20NO6P, m.p. 428-431 K, has been determined by X-ray diffraction. The title compound consists of a tetrahedral P atom bonded to two methoxy groups, and an alkyl chain. The alkyl chain was substituted at position 1 with a carbamate and with an epoxide at positions 2 and 3. The relative configuration of the 1-carbamate and 2,3-epoxide substituents was confirmed as anti (1S,2R,3S). The crystal structure contains an enantiomeric pair with two intermolecular hydrogen bonds in a 14-membered ring. The hydrogen bonds are formed between the P=O of one enantiomer and the N-H …

Probing The Intermolecular Hydrogen Bonding Of Water Molecules At The Ccl4/Water Interface In The Presence Of Charges Soluble Surfactant, D. E. Gragson, G. L. Richmond

Chemistry and Biochemistry

The molecular structure and hydrogen bonding of water molecules at the CCl₄/water interface in the presence of a charged soluble surfactant has been explored in this study using vibrational sum frequency generation. By examining OH stretching modes that are highly sensitive to the local hydrogen bonding environment it is found that water molecules at the CCl₄/water interface both in the presence and absence of a charged soluble surfactant are predominantly in a tetrahedral arrangement much like the structure ofice. Isotopic dilution studies have been employed to further characterize this icelike interfacial structure. Ablueshift ofapproximately120 cm^{-1 …}

Nucleotide Or Nucleoside Photoaffinity Compound Modified Antibodies, Methods For Their Manufacture And Use Thereof As Diagnostics And Therapeutics, Boyd E. Haley, Heinz Köhler, Krishnan Rajagopalan, Gabriela Pavlinkova

Chemistry Faculty Patents

Sites on antibodies having affinity for photoaffinity compounds, in particular purine or azidopurine containing compounds are taught. These sites provide for the site-specific attachment of nucleotide photoaffinity compounds to antibodies, e.g., ATP- or GTP-analog photoaffinity compounds by photochemical means. These nucleotide photoaffinity compounds may additionally be attached to molecules having a desired therapeutic or diagnostic activity, and the resultant conjugates used as diagnostics or therapeutics.

Proton Nuclear Magnetic Resonance Investigation Of The [2fe-2s]1--Containing “Rieske-Type” Protein From Xanthobacter Strain Py2, Richard C. Holz, Frederick J. Small, Scott A. Ensign

Chemistry Faculty Research and Publications

Proton NMR spectra of the Rieske-type ferredoxin from Xanthobacter strain Py2 were recorded in both H₂O and D₂O buffered solutions at pH 7.2. Several well-resolved hyperfine-shifted ¹H NMR signals were observed in the 90 to −20 ppm chemical shift range. Comparison of spectra recorded in H₂O and D₂O buffered solutions indicated that the signals at −11.4 (L) and −15.5 (M) ppm were solvent-exchangeable and thus were assigned to the two histidine N^ε2H protons. The remaining observed signals were assigned based upon chemical shift, T₁ values, and one-dimensional …

The Determination Of The Crystal Structure Of 2-Methyl-2methylacrylyl-Cyclohexanone- (1,5)-Diaxaspiro Mononeopentyl By X-Ray Christallography, Joann Stevenson

McCabe Thesis Collection

Cyclohexanone, the central component of the compound 2-methyl-2-methylacrylylcyclohexanone-( l,5)-diaxaspiro mononeopentyl (see figure on page 2), serves as a solvent for oil in piston type aircraft and in natural and vinyl resins. It is used in the production of crude rubber, waxes, fats, shellac and DDT and other pesticides. Cyclohexanone also is a part of the production of adipic acid, which is used to prepare nylon and is used to prepare cyclohexanone resins via condensation to enhance the adhesive properties of products like floor paints.

Cyclohexanones are among the most accessible hydroaromatic derivatives and serve as the initial materials for the …

Forensic Soil Analysis: Characterization Of The Sand Fraction, John Baize

Masters Theses & Specialist Projects

The purpose of this project was to develop a comprehensive analytical method for the characterization of soil by examining particle size, elemental composition, and percent organic matter in soil, and to determine its forensic applicability. In this study, five soils of varying geological locations were examined including two samples from Kentucky; two samples from Pennsylvania; and one from Washington D C A Gilson sonic sieve shaker was used to separate fractions of soil to determine particle size, and a JEOL scanning electron microscope with a Kevex EDS detector was used to determine elemental composition. These techniques coupled with percent total …

Development Of An Atmospheric Fluidized Bed Combustor (Afbc), William Orndorff

Masters Theses & Specialist Projects

The relatively recent interest in the U.S. in the development of atmospheric fluidized bed combustion (AFBC) has been preceded by two main factors. First of these is the ever present problem of acid rain and growing public support for cleaner burning fossil fuels. Second is the increasing demand on public landfills and subsequent need for burning of municipal solid waste. From these factors and their corresponding influences, Western Kentucky University has the impetus and has received the financial assistance necessary to build and develop a laboratory scale AFBC system. A brief history of the events leading to this development, as …

Studies On Resolution Of Enantiomeric Dialkylaryl Sulfonium Ions With Nmr Shift Reagents, Ea-Ji-Ru Son

Masters Theses & Specialist Projects

Praseodymium(III) NMR shift reagent, which is an upfield shift reagent, is focused on for assessment of enantiomeric excess and resolution of methyl sulfonium ions. A series of alkylmethylphenylsulfonium ions were analyzed, where alkyl is ethyl (I), butyl(H), octyl (III), and benzyl(IY). The praseodymium agent gives base-lined resolution of the ortho hydrogens resonance for I and IH. All spectra are strongly temperature-dependent. I is shifted more than ED, consistent with a steric effect. Assignments for I were made by gradually increasing the concentration of the shift reagent and by analyzing R-enriched I. Racemization of R-enriched isomer of I by pyramidal inversion …

A Study Of Polycyclic Aromatic Hydrocarbons During Combustion In An Afbc System, Laura Dicken

Masters Theses & Specialist Projects

The purpose of this study was to develop the on-line method of analysis which leads to the study of polycyclic aromatic hydrocarbons (PAHs) during combustion in an atmospheric fluidized bed combustor (AFBC) system. The study of PAHs is important because they may be produced upon the combustion of coal. The US EPA prioritizes PAHs as major pollutants due to their mutagenic and carcinogenic effects. Standards of PAHs were analyzed by injection into the gas chromatograph-mass spectrometer (GC-MS). These standards were then analyzed using the on-line method. Two coals were burned in the AFBC system and effluent samples were collected. These …

Fundamental Investigations Of Mechanistic Pathways Of Selected Organic Reactive Intermediates, Carl Whittle

Masters Theses & Specialist Projects

Part 1 of this thesis deals with the role that it -electron density plays in the formation of it -complexes in electrophilic aromatic substitution. Using commercial and synthetic compounds of varying it-electron density, the fact that % -complexes actually exist in these species was determined by a mass spectral investigation that was designed to monitor alkyl side-chain isomerizaitons. Also, the amount of it-complex was determined for each compound by measuring the amount of alkyl carbenium ion loss in each compound's mass spectrum. Found within the systems was an internal trend showing that the greater the amount of 7t-electron density in …

Temperature-Dependence Studies Of Photorefractive Effect In A Low Glass-Transition-Temperature Polymer Composite, Bogdan Swedek, Ning Cheng, Yiping Cui, Jaroslaw W. Zieba, Jeffrey G. Winiarz, Paras N. Prasad

Chemistry Faculty Research & Creative Works

The temperature dependence of the photorefractive effect in a polymer composite containing poly(9-vinycarbazole), tricresyl phosphate, buckminsterfullerene, and 4-(N,N-diethylamino)-β-nitrostyrene is presented. The photoconductive, electro-optic and photorefractive properties of the material have been studied in the temperature range of 22-61°C. An apparent increase of electro-optic modulation with temperature and its eventual saturation is observed. This behavior is attributed to the temperature activated orientational mobility of the second-order nonlinear chromophores. The polarization anisotropy between the p- and s-polarized readouts is consistent with what would be expected on the basis of directly measured effective electro-optic coefficients. By correlating the electro-optic value with the diffraction …

Pan, Ppn And Mpan Measurements And The Systematic Relationship Between Mpan And Macr At A Semi-Rural Site In Tennessee, George Nouaime

Masters Theses

Simultaneous measurements of peroxymethacryloyl nitrate (MPAN) and its primary and secondary precursors, methacarolein (MACR) and isoprene, were carried out for the first time in July 1995 at a semi-rural site southeast of Nashville. In addition to these compounds, peroxyacetyl nitrate (PAN), peroxypropionyl nitrate (PPN), other volatile organic compounds (VOCs) and supporting measurements were also collected in collaboration with other research groups. The mean concentrations of PAN, PPN, MPAN and MACR were found to be 485 pptv, 50 pptv, 30 pptv and 0.290 ppbv respectively. MP AN levels, which closely tracked those of MACR during the day, peaked and dropped earlier …

Near-Field Measurements On Contrail Properties From Fuels With Different Sulfur Content, Andreas Petzold, Reinhold Busen, Franz Peter Schroder, Robert Baumann, Markus Kuhn, Johan Strom, Donald E. Hagen, Philip D. Whitefield, Darrel G. Baumgardner, Frank Arnold, Stephan Borrmann, Ulrich Schumann

Physics Faculty Research & Creative Works

Microphysical properties of jet exhaust aerosol and contrails were studied in the near field of the emitting aircraft for different fuel sulfur contents. Measurements were performed behind two different aircraft (ATTAS test aircraft of type VFW 614 and Airbus A310-300) using fuels with sulfur contents of 6 ppm and 2700 ppm, respectively. At closest approach (plume age < 1 s), the total number concentrations exceeded the measuring range of the condensation particle counter, i.e., N > 10⁵ cm^-3. The concentration of the dry accumulation mode aerosol, i.e., predominantly soot particles, was not affected by the fuel sulfur content. At a plume age of 10 s, an increase in total number concentration (Dp > 0.01 μm) by a …

Freezing Of Confined Water: A Bilayer Ice Phase In Hydrophobic Nanopores, Kenichiro Koga, Xiao Cheng Zeng, Hideki Tanaka

Xiao Cheng Zeng Publications

Molecular dynamics simulations were performed to study the phase behavior of a thin film of water confined to a slit nanopore with smooth walls. A first-order water-to-ice freezing transition has been observed. The resulting ice, which is a crystal of bilayer consisting of rows of distorted hexagons, does not resemble any ice crystals found so far. The confined water contracts upon freezing when the confinement load is low ( ∼0.5 kbar) and expands when the load is high (10 kbar). The residual entropy of the bilayer ice can be calculated exactly, which is about half of the entropy of the …