Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

Chemistry

Institution
Keyword
Publication Year
Publication
Publication Type
File Type

Articles 30601 - 30630 of 34555

Full-Text Articles in Physical Sciences and Mathematics

Helical Stacking In Dna 3-Way Junctions Containing 2 Unpaired Pyrimidines - Proton Nmr-Studies, Neocles B. Leontis, Michael T. Hills, Martial Piotto, Igor V. Ouporov, Arun Malhotra, David G. Gorenstein Jan 1995

Helical Stacking In Dna 3-Way Junctions Containing 2 Unpaired Pyrimidines - Proton Nmr-Studies, Neocles B. Leontis, Michael T. Hills, Martial Piotto, Igor V. Ouporov, Arun Malhotra, David G. Gorenstein

Chemistry Faculty Publications

The proton NMR spectra of DNA three-way junction complexes (TWJ) having unpaired pyrimidines, 5'-TT- and 5'-TC- on one strand at the junction site were assigned from 2D NOESY spectra acquired in H2O and D2O solvents and homonuclear 3D NOESY-TOCSY and 3D NOESY-NOESY in D2O solvent. TWJ are the simplest branched structures found in biologically active nucleic acids. Unpaired nucleotides are common features of such structures and have been shown to stabilize junction formation. The NMR data confirm that the component oligonucleotides assemble to form conformationally homogeneous TWJ complexes having three double-helical, B-form arms. Two of the helical arms stack upon …


Ua35/11 Student Honors Research Bulletin, Wku Honors Program Jan 1995

Ua35/11 Student Honors Research Bulletin, Wku Honors Program

WKU Administration Documents

The WKU Student Honors Research Bulletin is dedicated to scholarly involvement and student research. These papers are representative of work done by students from throughout the university.

  • Allen, Melody. Women in Control of Courtship in As You Like It, The Merchant of Venice and All's Well That Ends Well
  • Amlani, Islamshah. Electron Stimulated Desorption of Alkali Halides
  • Brillhart, Kelly. Women Without Men: Hemingway's Female Characters
  • Burton, Lori. Financial Statements with Environmental Concerns: An Exploratory Study of the Impact on the Auditor's Role and Responsibilities
  • Combs, Vicki. Dancing the Descent: Energy and Entrophy in William Carlos Williams
  • Davis, Julie. Prelude to …


The Synthesis And Characterization Of Novel 5,6-Disubstituted 1,10-Phenanthrolines, Liansheng Zeng Jan 1995

The Synthesis And Characterization Of Novel 5,6-Disubstituted 1,10-Phenanthrolines, Liansheng Zeng

Masters Theses

Two new ligands, 5-amino-6-nitro-1,10-phenanthroline (5-NH2-6-NO2-phen), produced by amination of 5-NO2-1,10-phenanthroline, and 5,6-diamino-1,10-phenanthroline (5,6-(NH2) 2-phen) ,produced by reduction of 5-NH2-6-NO2-phen, have been synthesized and characterized. The ligand 5-NH2-6-NO2-phen has been coordinated to a Ru(II) metal center to produce the Ru(II)-polypyridine complex [ (bpy) 2Ru (5-NH2-6-NO2-phen)] (PF6 ) 2 (bpy= 2, 2' -bipyridine) . This complex has been characterized by IR, UV-Vis, 1H-NMR, and cyclic voltammetry (CV) .


Isomerization And Chelation Studies Of Dangling Phosphine Complexes Of Group 6, Zhongjiang Jia Jan 1995

Isomerization And Chelation Studies Of Dangling Phosphine Complexes Of Group 6, Zhongjiang Jia

Masters Theses

Vinyl addition reactions, catalyzed by 2,2'-azobis(isobutyronitrile) (AIBN), have been used to prepare six pentacarbonyl complexes of group 6, each of which contains a dangling Ph2PCH2CH2P(p-tol)2 ligand.

Each of the six complexes undergoes slow isomerizationand chelation at 55 °C in perdeuterated toluene:

The reactions were monitored by 31P{1H} NMR spectroscopy. The isomerization reactions are reversible in solution, while the chelated products form irreversibly with the loss of carbon monoxide. The rate constants, K1 and K-1, have been determined for the three pairs of linkage isomers. Equilibrium …


The Synthesis And Characterization Of [Ruii (Bpy) 2 (Biphen) ] (Pf6)2 And [ (Bpy) 2ruii (Biphen) Ruii (Bpy) 2] (Pf6)4, Mei-Yueh Chang Jan 1995

The Synthesis And Characterization Of [Ruii (Bpy) 2 (Biphen) ] (Pf6)2 And [ (Bpy) 2ruii (Biphen) Ruii (Bpy) 2] (Pf6)4, Mei-Yueh Chang

Masters Theses

A new bidentate polypyridine bridging ligand (biphen), produced by the condensation of 1,10-phenanthroline-5,6-dione with 5,6-diamino-phenanthroline has been synthesized and characterized. In addition the monometallic complex [(bpy)2RuII(biphen)](PF6)2 and the bimetallic complex [(bpy)2RuII(biphen)RuII(bpy)2](PF6)4 have been prepared. The complexes were characterized by elemental analysis, by 1H-NMR spectroscopy and by cyclic voltsmmetry(CV).

The results of these analyses seem to indicate that biphen acts like two independent units when attached to a - RuII(bpy)2 fragment. a bipyridine portion and a phenazine portion. Moreover, …


The Synthesis Of N-Chlorosulfonyl Β-Lactams And Their Rearrangements, Lihua Zhang Jan 1995

The Synthesis Of N-Chlorosulfonyl Β-Lactams And Their Rearrangements, Lihua Zhang

Masters Theses

The synthesis of several N-chlorosulfonyl-β-lactams and their rearrangements have been carried out via CSI (chlorosulfonylisocyanate) reaction. The mechanism of β-lactam synthesis as well as its rearrangements were also studied. The characterization of β-lactams was performed with IR, 1H and 13C NMR, and HRMS. β-lactams 2-chlorosulfonyl-1-methyl-2-azabicyclo[4.2.0]octan-3-one (71), 1-chlorosulfonyl-4-methyl-4- (phenylmethyl)azetidin-2-one (74) and 1-chlorosulfonyl-4,4- (diphenylmethyl)azetidin-2-one (75) were synthesized for the first time. β-lactam 4-chlorosulfonyl-3, 9, 9-trimethyl-4-azatricyclo [6.1.0.03,6] nonan-5-one (73) was obtained as crystalline solid instead of liquid.

Different effects, such as temperature, solvents and catalysts, on the rearrangement of the …


Novel Compounds (Including Transition-Metal Complexes) Based On 1,10-Phenanthroline-5,6-Dione, Hui Zhou Jan 1995

Novel Compounds (Including Transition-Metal Complexes) Based On 1,10-Phenanthroline-5,6-Dione, Hui Zhou

Masters Theses

This thesis describes the synthesis of the transition metal complex [(bpy) 2OsII (pptd)] (PF6)2·2H2O, an analog of [(bpy) 2RuII (pptd)] (PF6)2·2H2O. Spectroscopic and electrochemical data on this complex are reported here. It was found that the electronic communication between the metal center and the pteridinedione portion of pptd did not appear to be enhanced in the Os(II) complex relative to its Ru(II) analog. The increased ability of Os(II) to undergo backbonding appeared to affect only the 1,10-phenanthroline portion of pptd.

A useful …


Equilibrium And Kinetic Studies Of Isomerization Of (Oc)5m[Η1-Pph2ch2ch(Pph2)2] And (Oc)5m[Η1-Pph2ch(Pph2)Ch2pph2] (M=Cr, Mo, W), Weiying Lin Jan 1995

Equilibrium And Kinetic Studies Of Isomerization Of (Oc)5m[Η1-Pph2ch2ch(Pph2)2] And (Oc)5m[Η1-Pph2ch(Pph2)Ch2pph2] (M=Cr, Mo, W), Weiying Lin

Masters Theses

It has been found that (OC)5M[η1-PPh2CH2CH(PPh2)2] and (OC)5M[η1-PPh2CH(PPh2)CH2PPh2] (M=Cr, Mo, W) exist in equilibrium in solution. This linkage isomerization is the first experimental evidence for the exchange of terminal and coordinated phosphorus groups in pentacarbonyl complexes of group 6 metals.

(OC)5M[η1-PPh2CH2CH(PPh2)2] ⇌ (OC)5M[η1-PPh2CH(PPh2)CH2PPh2]

(M = Cr, Mo, W)

In this work, equilibrium …


Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen Jan 1995

Acid Dissociation Of Chloroguaiacols And Ph Dependent Sorption To Estuarine Sediments, Jennifer Lisa Gundersen

Dissertations, Theses, and Masters Projects

Chloroguaiacols are common components of bleached kraft pulp mill effluent known to bioaccumulate in aquatic organisms, and sorb onto particulate material and sediments. Ionization properties of the chloroguaiacols must be known in order to explain their sorptive behavior in aquatic systems. to obtain this information, thermodynamic acid dissociation constants (p&K\sb{lcub}\rm a{rcub})& of guaiacol (o-methoxyphenol) and nine chloroguaiacols have been determined by spectrophotometric methods. These experimental p&K\sb{lcub}\rm a{rcub}& values have been compared with literature values, values predicted by the Hammett equation and predictions by quantum chemical calculations using MOPAC 6.0 with AM1 and MNDO Hamiltonian operators. Experimental and predicted acidities were …


Metallization Of Polyimide Films To Enhance Dimensional Stability And To Achieve Reflective And Conductive Surfaces, David Scott Thompson Jan 1995

Metallization Of Polyimide Films To Enhance Dimensional Stability And To Achieve Reflective And Conductive Surfaces, David Scott Thompson

Dissertations, Theses, and Masters Projects

No abstract provided.


Continuous Electron Stimulated Oxygen Atom Emission From Ag Permeation Membranes, Gilda Ann Newton Miner Jan 1995

Continuous Electron Stimulated Oxygen Atom Emission From Ag Permeation Membranes, Gilda Ann Newton Miner

Dissertations, Theses, and Masters Projects

No abstract provided.


Designing Chemical Education Hypermedia For The World-Wide Web, Brian Tissue, Ching-Wan Yip, Yue-Ling Wong, Mark Anderson Dec 1994

Designing Chemical Education Hypermedia For The World-Wide Web, Brian Tissue, Ching-Wan Yip, Yue-Ling Wong, Mark Anderson

Mark R. Anderson

No abstract is currently available.


Determination Of Plasma Parameters In A Dc Arcjet Part Ii, Scott Reeve, Wayne Weimer Dec 1994

Determination Of Plasma Parameters In A Dc Arcjet Part Ii, Scott Reeve, Wayne Weimer

Scott Reeve

No abstract provided.


Collective Expansion In Central Au+Au Collisions, W. C. Hsi, G. J. Kunde, J. Pochodzalla, W. G. Lynch, M. B. Tsang, M. L. Begemann-Blaich, D. R. Bowman, R. J. Charity, F. Cosmo, A. Ferrero, C. K. Gelbke, T. Glasmacher, T. Hofmann, G. Imme, I. Iori, J. Hubele, J. Kempter, P. Kreutz, W. D. Kunze, V. Lindenstruth, M. A. Lisa, U. Lynen, M. Mang, A. Moroni, W. F.J. Müller, M. Neumann, B. Ocker, C. A. Ogilvie, Graham F. Peaslee, G. Raciti, F. Rosenberger, H. Sann, R. Scardaoni, A. Schüttauf, C. Schwarz, W. Seidei, V. Serfling, L. G. Sobotka Dec 1994

Collective Expansion In Central Au+Au Collisions, W. C. Hsi, G. J. Kunde, J. Pochodzalla, W. G. Lynch, M. B. Tsang, M. L. Begemann-Blaich, D. R. Bowman, R. J. Charity, F. Cosmo, A. Ferrero, C. K. Gelbke, T. Glasmacher, T. Hofmann, G. Imme, I. Iori, J. Hubele, J. Kempter, P. Kreutz, W. D. Kunze, V. Lindenstruth, M. A. Lisa, U. Lynen, M. Mang, A. Moroni, W. F.J. Müller, M. Neumann, B. Ocker, C. A. Ogilvie, Graham F. Peaslee, G. Raciti, F. Rosenberger, H. Sann, R. Scardaoni, A. Schüttauf, C. Schwarz, W. Seidei, V. Serfling, L. G. Sobotka

Faculty Publications

Energy spectra for intermediate mass fragments produced in central Au + Au collisions at EA=100 MeV indicate a collective expansion at breakup. For the first time, values for this collective expansion energy per nucleon are extracted independently for each charge. Typically, these values are one-third to one-half of the incident kinetic energy per nucleon in the c.m. system, but they decrease with Zf, suggesting that all fragments do not participate equally in the collective expansion.


Fragmentation Of Necklike Structures, C. P. Montoya, W. G. Lynch, D. R. Bowman, Graham F. Peaslee, N. Carlin, R. T. De Souza, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, L. Phair, M. B. Tsang, J. B. Webster, C. Williams, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak, L. G. Moretto Dec 1994

Fragmentation Of Necklike Structures, C. P. Montoya, W. G. Lynch, D. R. Bowman, Graham F. Peaslee, N. Carlin, R. T. De Souza, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, L. Phair, M. B. Tsang, J. B. Webster, C. Williams, N. Colonna, K. Hanold, M. A. Mcmahan, G. J. Wozniak, L. G. Moretto

Faculty Publications

Intermediate mass fragment (IMF: 3≤Z≤20 emission from necklike structures joining projectilelike and targetlike residues has been observed for peripheral Xe129 + Cunat collisions at EA=50 MeV. These fragments are emitted primarily at velocities between those of the projectilelike and targetlike residues. Relative to the charge distribution of fragments evaporated from projectilelike residues, the distribution for "neck" emission shows an enhanced emission for fragments with 4≤ZIMF≤12. This feature is consistent with expectations for the fragmentation of a noncompact cylindrical configuration.


Sixth U.S.-Japan Seminar On Polymer Synthesis: Macromolecular Design For Advanced Materials, Otto Vogl, Shiro Kobayashi Dec 1994

Sixth U.S.-Japan Seminar On Polymer Synthesis: Macromolecular Design For Advanced Materials, Otto Vogl, Shiro Kobayashi

Otto Vogl

No abstract provided.


Polymer Institute Slovak Academy Of Sciences Bratislava, Slovakia, Otto Vogl Dec 1994

Polymer Institute Slovak Academy Of Sciences Bratislava, Slovakia, Otto Vogl

Otto Vogl

No abstract provided.


64. Tibor Kelen, Otto Vogl Dec 1994

64. Tibor Kelen, Otto Vogl

Otto Vogl

No abstract provided.


Foam Flotation Enrichment Of Enantiomers, Daniel W. Armstrong, Eve Y. Zhou, Shushi Chen, Kang Le, Yubing Tang Dec 1994

Foam Flotation Enrichment Of Enantiomers, Daniel W. Armstrong, Eve Y. Zhou, Shushi Chen, Kang Le, Yubing Tang

Chemistry Faculty Research & Creative Works

Adsorptive bubble separation methods are known to be useful for processing large amounts of material at a relatively low cost These techniques have been used to enrich components from both heterogeneous and homogeneous solutions. There is a need for economical process-scale enantiomeric separations. Thus far there has been little evidence to support the feasibility of using an adsorptive bubble process to enrich enantiomers. We demonstrate that foam-forming chiral collectors can be used in conjunction with an inexpensive glass device to enantiomerically enrich some pharmaceutically important compounds as well as derivatized and underivatized amino acids. Factors that appeared to affect this …


Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume Ii Of Ii, National Park Service Dec 1994

Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume Ii Of Ii, National Park Service

Publications (WR)

This document presents the results of surface-water-quality data retrievals for Lake Mead National Recreation Area (LAME) from five of the United States Environmental Protection Agency's (EPA) national databases: (1) Storage and Retrieval (STORET) database management system; (2) River Reach File (RF3); (3) Industrial Facilities Discharge (IFD); (4) Drinking Water Supplies (DRINKS); and (5) Flow Gages (GAGES). This document is one product resulting from a cooperative contractual endeavor between the National Park Service's Servicewide Inventory and Monitoring Program, the National Park Service's Water Resources Division (WRD), and Horizon Systems Corporation to retrieve, format, and analyze water quality data for all units …


Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume I Of Ii, National Park Service Dec 1994

Baseline Water Quality Data Inventory And Analysis: Lake Mead National Recreation Area, Volume I Of Ii, National Park Service

Publications (WR)

This document presents the results of surface-water-quality data retrievals for Lake Mead National Recreation Area (LAME) from five of the United States Environmental Protection Agency's (EPA) national databases: (1) Storage and Retrieval (STORET) database management system; (2) River Reach File (RF3); (3) Industrial Facilities Discharge (IFD); (4) Drinking Water Supplies (DRINKS); and (5) Flow Gages (GAGES). This document is one product resulting from a cooperative contractual endeavor between the National Park Service's Servicewide Inventory and Monitoring Program, the National Park Service's Water Resources Division (WRD), and Horizon Systems Corporation to retrieve, format, and analyze water quality data for all units …


The Reaction Of Caffeic Acid And Copper (Ii) In Natural Water, Ling Xiaozheng Xu Dec 1994

The Reaction Of Caffeic Acid And Copper (Ii) In Natural Water, Ling Xiaozheng Xu

Masters Theses

The interaction of the lignin precursor compound caffeic acid with copper(lI) in aqueous solution was studied. In the presence of a reducible transition metal, such as copper, caffeic acid undergoes oxidation. Oxygen was shown to play an important role in the reaction. The UV-visible data demonstrated that the conjugated double bond in the propenoic acid side chain of caffeic acid slowly disappeared during the reaction. The molecular weight experiments indicated that the product was a dimer. FTIR spectrum agreed with two possible dimer structures involving the side chain of caffeic acid. In addition, the reaction was shown to be reversible. …


Investigation Of The Effect Of Structure On Reactivity In The Titanium Dioxide Mediated Photodecomposition Of Phenols And Haloethers When Irradiated At 350 Nm In An Aqueous Medium, Claudia Cardona Nov 1994

Investigation Of The Effect Of Structure On Reactivity In The Titanium Dioxide Mediated Photodecomposition Of Phenols And Haloethers When Irradiated At 350 Nm In An Aqueous Medium, Claudia Cardona

FIU Electronic Theses and Dissertations

Three studies were performed to obtain fundamental mechanistic information on the TiO2 catalyzed photooxidations of organic substrates irradiated at 350 nm in dilute aqueous solutions under oxygenated conditions: (a) The photodecomposition of three haloethers, 2-chloroethyl ether, 4-chlorophenyl phenyl ether, and 4-bromophenyl phenyl ether, was investigated in an aqueous media at pH 7.0. (b) A comparative study of structure-reactivity was conducted on para-substituted phenols whose substituents range from electron-withdrawing to electron-donating in an aqueous media at pH 3.0. (c) The initial rates of the TiO2 catalyzed photodegratation of phenol were studied in an aqueous media at pH 1.0, …


65. Ferenc Tudos, Otto Vogl Nov 1994

65. Ferenc Tudos, Otto Vogl

Otto Vogl

No abstract provided.


Third Pacific Polymer Conference. Gold Coast - Australia, Otto Vogl, Graeme A. George Nov 1994

Third Pacific Polymer Conference. Gold Coast - Australia, Otto Vogl, Graeme A. George

Otto Vogl

No abstract provided.


Polymer Science In Australia I. Sydney And Canberra, Otto Vogl, Donald H. Napper Nov 1994

Polymer Science In Australia I. Sydney And Canberra, Otto Vogl, Donald H. Napper

Otto Vogl

No abstract provided.


Time Scale For Multifragmentation In Intermediate Energy Heavy-Ion Reactions, D. Fox, R. T. De Souza, T. Glasmacher, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu Nov 1994

Time Scale For Multifragmentation In Intermediate Energy Heavy-Ion Reactions, D. Fox, R. T. De Souza, T. Glasmacher, L. Phair, D. R. Bowman, N. Carlin, C. K. Gelbke, W. G. Gong, Y. D. Kim, M. A. Lisa, W. G. Lynch, Graham F. Peaslee, M. B. Tsang, F. Zhu

Faculty Publications

Fragment-fragment correlations are used to probe the spatial-temporal extent of the emitting source in central Ar36+197Au reactions at E/A=35, 50, 80, and 110 MeV. The experimental two particle correlations are compared both with the Koonin-Pratt two-body formalism as well as a three-body Coulomb trajectory calculation. The spatial-temporal extent of the emitting system decreases with increasing incident energy. Within the context of a three-body Coulomb trajectory model the mean fragment emission time rises sharply as a function of the assumed density of the system until ρ/ρ0≊0.3. If one assumes a fixed density, the extracted mean emission time decreases with increasing assumed …


Application Of Fractals And Kinetic Equation In Modelling Cluster And Ultrafine Particle Size Distributions, Joseph Chaiken, Jerry Goodisman Nov 1994

Application Of Fractals And Kinetic Equation In Modelling Cluster And Ultrafine Particle Size Distributions, Joseph Chaiken, Jerry Goodisman

Chemistry - All Scholarship

We briefly describe a model which seems to be applicable to a variety of coalescence growth systems. Spanning cluster growth, particle growth and hillock formation in thin metal films, this model is based on the Smoluchowski kinetic equations and fractals. We describe how this model has been able to suggest the effect of translational to internal energy conversion in coalescing systems in determining the shape of particle size distributions. We also suggest how this model can be employed to account for the behavior of hillocks in supersaturated alloy films under thermal annealing conditions.


Semiclassical Quantization Of A Nonintegrable System: Pushing The Fourier Method Into The Chaotic Regime, Karl Sohlberg, Randall B. Shirts Nov 1994

Semiclassical Quantization Of A Nonintegrable System: Pushing The Fourier Method Into The Chaotic Regime, Karl Sohlberg, Randall B. Shirts

Faculty Publications

Semiclassical Einstein–Brillouin–Keller (EBK) quantization of the nonintegrable Hénon–Heiles Hamiltonian succeeds using the Fourier transform method of Martens and Ezra. Two innovations are required for this success: (1) the use of tunneling corrected quantizing actions obtained from an approximate, one-dimensional Hamiltonian and (2) exploitation of intermediate-time approximate quasiperiodicity or "vague tori'' wherein the Fourier transform of chaotic motion over 10–100 vibrational periods allows the determination of frequencies and amplitudes which approximate motion during the time interval. Approximate tori, actions, and EBK energy levels are then straightforward. We use an interpolation method to smooth over small resonance zones that are not expected …


Three-Body Analytical Potential For Interacting Helium Atoms, Carol A. Parish, Clifford E. Dykstra Nov 1994

Three-Body Analytical Potential For Interacting Helium Atoms, Carol A. Parish, Clifford E. Dykstra

Chemistry Faculty Publications

Large basis set ab initio calculations have been carried out for a dense grid of points on the He, potential energy surface. Three-body contributions were extracted at every point, and a number of concise functional representations for the three-body potential surface were then examined. Three-body multipolar dispersion terms and other radial and angular terms were used in the representations, and an assessment of relative importance of the different terms is presented. Combined with a two-body He-He potential, the results of this work should offer a high quality interaction potential for simulations of aggregated helium.