Physical Sciences and Mathematics Commons^™

Potential Energy Surfaces For The Reaction Si (Silicon) + H2o (Water), Shogo Sakai, Mark S. Gordon, Kenneth D. Jordan

Mark S. Gordon

The potential energy surfaces for the reactions of silicon atom (ID and 3P) with the water molecule were calculated by ab initio self-consistent field (SCF) methods. The transition states for the insertion of silicon atom into the D--H bond of water were also calculated by the multiconfigurational SCF method. It is found that the crossing point of the singlet and triplet surfaces along the insertion reaction paths is near the transition state for the triplet rearrangement from the Si:OH2 complex to HSiOH. The potential energy surfaces for the 1,2-hydrogen migration HSiOH- H2Si0 in the singlet and triplet states and the …

Polymer Science In Romania I: "Petru Poni" Institute Of Macromolecular Chemistry, Iasi, Romania, Otto Vogl, Cristofor I. Simionescu, Ioan I. Negulescu

Otto Vogl

No abstract provided.

U.S.-Japan Seminar: "Synthesis, Properties And Reactions Of Specialty Polymers", Otto Vogl, Hiroshi Sumitomo

Otto Vogl

No abstract provided.

Micellar Catalyzed Hydrolysis Of Hydroxamic Acids By Perfluorooctanoic Acid, Mohammad Hashem Akhavan Tafti

Masters Theses

The work reported herein demonstrated that a perfluorocarboxylic acid does indeed behave as a reactive counterion surfactant exhibiting micellar catalysis, this conclusion was further verified by subsequent experimentation.

Rates of acidic hydrolysis of octano-, phenylaceto-, and 4-bromo phenylacetohydroxamic acid have been determined in aqueous perfluorooctanoic acid--a reactive counterion surfactant system. Typical micellar catalysis was observed for the hydrolysis of octanohydroxamic acid but not for the arylacetohydroxamic acids.

Further investigation into finding a more water soluble surfactant which has reactive counter ions is suggested in order to test the theoretical equation (based on the pseudo phase model) appropriate for this surfactant …

Anti-Cancer Action Of Metal Complexes: Electron Transfer And Oxidative Stress?, Peter Kovacic, William J. Popp, James R. Ames, Michael D. Ryan

Chemistry Faculty Research and Publications

Evidence is presented in support of an electron transfer mechanism for various metal complexes possessing anti-neoplastic properties. Cyclic voltammetry was performed on several metallocenes, bis(acetato)bis(imidazole)Cu(II), and coordination compounds (Cu or Fe) of the anti-tumor agents, bipyridine, phenanthroline, hydroxyurea, diethyldithiocarbamate, and α, α¹-bis(8-hydroxyquinolin-7-yl)-4-methoxytoluene. The favorable reduction potentials ranged from +0.5 to -0.5 V. Electrochemical behavior is correlated in some cases with structure and physiological activity. Relevant literature data are discussed.

Synthesis Of N And C Nucleosides Via Cycloaddition Reactions A New Approach To An Old Problem, Glenn L. Heise

Dissertations

No abstract provided.

Surface-Enhanced Raman Study: Effect Of Ph And Electrode Potential On The Interfacial Behavior Of Some Substituted Pyridines, Mark Anderson, Daniel Evans

Mark R. Anderson

The surface-enhanced Raman spectra (SERS) provide information about the extent of protonation of the species adsorbed at the silver/aqueous solution interface. The compounds investigated were 4-pyridylcarbinol (1), 4-acetylpyridine (2), 3-pyridinecarboxaldehyde (3), isonicotinic acid (4), isonicotinamide (5), 4-benzoylpyridine (6), 4-(aminomethyl)pyridine (7) and 4-aminopyridine (8). For 1, the fraction of the adsorbed species which was protonated at -0.20 V vs. SCE varied with pH in a manner indicating stronger adsorption of the neutral than the cationic form. The fraction protonated increased at more negative potentials. Similar results were obtained with 3. For all compounds but 4, bands due to the unprotonated species …

31st International Congress Of Pure And Applied Chemistry, Sofia, Bulgaria,1987, Otto Vogl, Ivan Shopov, Ivan Panayotov

Otto Vogl

No abstract provided.

Polymer Science In Czechoslovakia Ii: Universities In The Czech Socialist Republic, Otto Vogl, Jaroslav Kralicek, Miroslav Schatz, Petr Vondracek

Otto Vogl

No abstract provided.

A Mössbauer Effect Study Of Y₂Fe₁₄B And Its Aluminum Solid Solutions, Dwayne E. Tharp, Gary J. Long, Oran Allan Pringle, Gaya Kanishka Marasinghe, William Joseph James, Fernande Grandjean

Chemistry Faculty Research & Creative Works

The Mössbauer spectra of Y₂Fe₁₄B have been measured from 85 to 296 K. Analysis of the spectra indicates that the near-neighbor rare-earth atoms directly influence the orientation of the principal axis of the electric field gradient. The hyperfine parameters are very similar to those of Nd₂Fe₁₄B, but the internal fields are somewhat smaller at room temperature in the yttrium compound. The Mösssbauer spectra of Y₂(Fe_1-xAl_x) ₁₄B, where x equals 0.00, 0.02, 0.04, 0.06, and 0.08, have been measured at 85 K. The average internal hyperfine …

Interactions Of Water-Soluble Metalloporphyrins With Nucleic Acids Studied By Resonance Raman Spectroscopy, Jinghua H. Schneider, Junichi Odo, Kazuo Nakamoto

Chemistry Faculty Research and Publications

The resonance Raman spectra of water-soluble porphyrins, M(TMpy-P4) (M = Cu(II), Ni(II) and Co(III)) and their mixtures with poly(dG-dC)₂, poly(dA-dT)₂ and calf thymus and salmon DNAs were measured using a divided rotating cell to determine the magnitudes of frequency shift and intensity variation resulting from M(TMpy-P4)-nucleic acid interactions. Bands II(Cβ-H bending, ˜ 1100 cm-1) and VIII(Cβ-Cβ stretch, ˜ 1570 cm-1) show a large and small upward shift, respectively, when Cu(TMpy-P4) and Ni(TMpy-P4) are intercalated at the G-C sites. In contrast, these bands show a small upward and downward shift, respectively, when Co(TMpy-P4) is groove-bound at the A-T …

Sulfide In Surface Waters Of The Western Atlantic Ocean, Gregory A. Cutter, Christian F. Krahforst

OES Faculty Publications

Using newly developed techniques, some preliminary data on hydrogen sulfide in surface waters of the western Atlantic have been obtained. Concentrations of total sulfide range from <0.1 to 1.1 nmol/L, and vary on a diel basis. At these concentrations, sulfide may affect the cycling of several trace metals via the formation of stable complexes. Production of sulfide in oxygenated seawater may occur through the hydrolysis of carbonyl sulfide or by sulfate reduction within macroscopic particles in the water column. Removal mechanisms can include oxidation, complexation with particulate trace metals, and metal sulfide precipitation. However, the temporal and spatial distributions suggest a complex set of processes governing the behavior of sulfide in the surface ocean.

A Neutron Diffraction And Mössbauer Spectral Study Of The Structure And Magnetic Properties Of The Y₂Fe₁₄₋ₓsiₓb Solid Solutions, Gaya Kanishka Marasinghe, Oran Allan Pringle, Gary J. Long, William B. Yelon, Fernande Grandjean

Physics Faculty Research & Creative Works

A neutron diffraction and Mössbauer spectral study of Y₂Fe_14-xSi_xB shows that silicon preferentially occupies the 4c, and to a lesser extent, the 8j₁ sites in Y₂Fe_14-xSi_xB. The trend in the site occupancy is the same as in Nd₂Fe_14-xSi_xB. The Curie temperature of Y₂Fe_14-xSi_xB increases with increasing silicon content. Neutron diffraction data show that the increase in Curie temperature is accompanied by a contraction of the unit cell. Wigner-Seitz cell calculations, using the Y₂Fe …

Dynamics Of Chain Molecules, Walter H. Stockmayer

DSLS 1988-1989

(Abstract taken from the Distinguished Scientist Lecture Series Program 1988-1989).

The recording of lecture not available.

Dr. Stockmayer is the Albert W. Smith Professor Emeritus at Dartmouth College, a position he has held since 1979. In 1935, Dr. Stockrnayer graduated from Massachusetts Institute of Technology. After two years at Oxford University, he returned to M.1.T. and earned his Ph.D. degree in 1940. His thesis, directed by James A. Beattie, was on the equation of state of gas mixtures. Dr. Stockrnayer became an Instructor in Chemistry at M.I.T. in 1939. Except for a two-year stint at Columbia University, he taught at …

Inulin-125I-Tyramine, An Improved Residualizing Label For Studies On Sites Of Catabolism Of Circulating Proteins, Janet L. Maxwell, John W. Baynes, Suzanne R. Thorpe

Faculty Publications

Residualizing labels for protein, such as dilactitol-125I-tyramine (125I-DLT) and cellobiitol-125I-tyramine, have been used to identify the tissue and cellular sites of catabolism of long-lived plasma proteins, such as albumin, immunoglobulins, and lipoproteins. The radioactive degradation products formed from labeled proteins are relatively large, hydrophilic, resistant to lysosomal hydrolases, and accumulate in lysosomes in the cells involved in degradation of the carrier protein. However, the gradual loss of the catabolites from cells (t1/2 approximately 2 days) has limited the usefulness of residualizing labels in studies on longer lived proteins. We describe here a higher molecular weight (Mr approximately 5000), more efficient …

Relative Energies Of Silaethylene And Methylsilylene, Roger S. Grev, Gustavo E. Scuseria, Andrew C. Scheiner, Henry F. Schaefer Iii, Mark S. Gordon

Mark S. Gordon

The energy difference between silaethylene (H2Si=CH2) and methylsilylene (SiHMe) has been determined with ab initio quantum chemical techniques. Large basis sets and a variety of methods for the inclusion of electron correlation effects have been employed. In direct contrast to the recent theoretical and experimental results of Shin, Irikura, Beauchamp, and Goddard, which suggested silaethylene was 10 kcaljmol more stable than methylsilylene, we find the energy difference to be nearer 4 kcal/mol.

Slip, Twinning, And Fracture At A Grain Boundary In The L12 Ordered Structure—Aς = 9 Tilt Boundary, Alexander H. King, M. H. Yoo

Alexander H. King

The role of interaction between slip dislocations and a Σ = 9 tilt boundary in localized microplastic deformation, cleavage, or intergranular fracture in the Li2 ordered structure has been analyzed by using the anisotropic elasticity theory of dislocations and fracture. Screw superpartials cross slip easily at the boundary onto the (1$\overline 1$1) and the (001) planes at low and high temperatures, respectively. Transmission of primary slip dislocations onto the conjugate slip system occurs with a certain degree of difficulty, which is eased by localized disordering. When the transmission is impeded, cleavage fracture on the ($\overline 1$11) plane is predicted to …

Iupac “Macro 87” In Merseburg (Gdr) Linking Tradition And Future In Polymer Science, Otto Vogl, Burkart Philipp

Otto Vogl

No abstract provided.

Sources Of Light-Charged-Particle Emission In The Reaction 480 Mev 56fe + Natag, Graham F. Peaslee, N. N. Ajitanand, John M. Alexander, D. Guerreau, Roy Lacey, L. C. Vaz, Morton Kaplan, M. Kildir, D. J. Moses, D. Logan, M. S. Zisman

Faculty Publications

Inclusive and exclusive measurements of light-charged particles (1,2,3H,4He) and heavy fragments have been made for the reaction 480 MeV 56Fe+natAg. The backward hemisphere emission of He4 and H1 in coincidence with a heavy fragment can be well described by evaporative emission from a combination of three sources: the detected fragment, the undetected fragment, and the composite system prior to scission. Multiplicities for each of these sources are determined for two coincident fragment groups: a fusion-fission-like group and a deeply-inelastic-reaction group. These multiplicities have also been studied at two angles for the trigger fragment (θTR=26° and 50°). For θTR=26° the multiplicity …

Enantiomeric Resolution And Chiral Recognition Of Racemic Nicotine And Nicotine Analogues By Β-Cyclodextrin Complexation: Structure-Enantiomeric Resolution Relationships In Host-Guest Interactions, Jeffrey I. Seeman, Henry V. Secor, Daniel W. Armstrong, Karen D. Timmons, Timothy J. Ward

Chemistry Faculty Research & Creative Works

High-performance liquid chromatography using β-cyclodextrin bonded phases was examined for the enantiomeric separation of racemic nicotine and 19 racemic nicotine analogues. Ten pairs of enantiomers were separated by this technique. This represents the first reported facile and direct separation of these racemates. Effects of pH, mobile phase composition, and structural features of the substrates (i.e., position and size of substituents, presence of pyrrolidine ring or hydrogen bonding functionalities, basicity) on the enantioselectivity are examined. Various structural aspects of the compounds were related to retention to the cyclodextrln-modlfied support and to the enantiomeric separations observed. Implications of this work to host-guest …

Kinetics And Mechanisms Of The Aminolysis Of N-Hydroxysuccinimide Esters In Aqueous Buffers, Gary W. Cline, Samir B. Hanna

Chemistry Faculty Research & Creative Works

Rate constants for the aminolysis of the N-hydroxysuccinimide (NHS) ester of ρ-methoxybenzoic acid, in aqueous buffer systems (20% dioxane), have been determined under pseudo-first-order conditions. For the amines studied (pK_a = 7.60-11.1), the data fit the rate expression k_obsd - K_OH-⨯ [OH-] = k₁[amine]_free. This rate equation is in contrast to the two-term rate equation (k_obsd = k₁[amine] + k₂[amine]²) obtained for this reaction in anhydrous dioxane (Cline, G. W.; Hanna, S. B. J. Am. Chem. Soc. 1987,109, 3087) and is suggestive of a disproportionate …

Use Of Secondary Equilibria For The Separation Of Small Solutes By Field-Flow Fractionation, Alain Berthod, Daniel W. Armstrong, J. Calvin Giddings, Marcus N. Myers

Chemistry Faculty Research & Creative Works

The dynamic range and selectivity of field-flow fractionation (FFF) can be Increased by using secondary chemical equilibria (SCE). SCE are established by adding a macromolecular additive or aggregate, which strongly Interacts with the field, to the carrier solution. In this study an oil-ln-water (O/W) microemulsion was used as the carrier solution in a sedimentation FFF apparatus. The microemulsion droplets (referred to as the "support") interact with the field and are retained relative to the bulk water. Small solutes that partition or bind to the microemulsion droplets are also retained relative to solutes that do not Interact with the support. In …

Ua66/7/2 Hilltopper News, Wku Chemistry

WKU Administration Documents

Newsletter created by and about the WKU Chemistry department.

Optimization Of The Tungstic Acid Denuder Technique For The Measurement Of Atmospheric Ammonia, Patricia Diane Roberts

Chemistry & Biochemistry Theses & Dissertations

Measurement of - atmospheric ammonia with the tungstic acid denuder technique is discussed. Characterization of denuder tubes for manual sampling in terms of, repeatability, reliability and the development of ammonia blank signals was determined. Field testing of the manual sampling apparatus was performed at ground test sites and in a biomass burn smoke plume. Ammonia emissions from biomass burning are discussed.

The Synthesis And Evaluation Of 5-Phenyloxazolidines As Potential Cardiovascular Drugs, Tammy C. Wang

Chemistry & Biochemistry Theses & Dissertations

Drugs such as adrenoceptor antagonists and certain centrally acting agents are known to lower blood pressure and thus serve as clinically useful antihypertensive agents. Norepinephrine 4, a natural ∝-adrenoceptor agonist, is the major agent associated with increased blood pressure in the periphery. Based on a careful structure-activity comparison, a series of substituted oxazolidines, 20, 21, 22 and 23, have been designed as possible antihypertensive candidates. Specifically, 22 and 23 have been synthesized to serve as potential norepinephrine antagonists.

Preliminary evaluation of these compounds indicated that they were not antihypertensive in nature. The more active compound, 23, …

Gas-Phase And Computational Studies Of Pentacoordinate Silicon, Robert Damrauer, Larry W. Burggraf, Larry P. Davis, Mark S. Gordon

Mark S. Gordon

We have demonstrated that a wide variety of pentacoordinate silicon anions (siliconates) should be stable and can be prepared by combining the predictive powers of MNDO and ab initio computational methods and the flowing afterglow (FA) experimental technique. MNDO has been used to compute the anion affinities of 91 siliconates; all but five of these are predicted to be stable with respect to the loss of an anion. Twenty-four siliconates, most of them previously unreported, have been prepared and studied in the FA. The MNDO predictions were, in general, consistent with the experimental results and with trends previously reported by …

Transport Properties Of Ground State Oxygen Atoms, Paul M. Holland, Louis Biolsi Jr.

Chemistry Faculty Research & Creative Works

The transport properties of dilute monatomic gases depend on the two body interactions between like atoms. When two ground state oxygen atoms interact, they can follow any of 18 potential energy curves corresponding to O₂, all of which contribute to the transport properties of the ground state atoms. Transport collision integrals have been calculated for those interactions with an attractive minimum in the potential by accurately representingab initio quantum mechanical potential energy curves with the Hulburt-Hirschfelder potential. Repulsive ab initio potential energy curves have been accurately represented either with the exponential repulsive potential or with an exponential …

Surface-Enhanced Raman Study Of The Effect Of Electrode Potential And Solution Ph Upon The Interfacial Behavior Of 4-Pyridinecarboxaldehyde, Mark Anderson, Dennis Evans

Mark R. Anderson

Surface-enhanced Raman scattering (SERS) spectra were obtained at a silver electrode in aqueous solutions at potentials from -0.2 to -0.6 V vs SCE and pH 1-7. The forms of 4-pyridinecarboxaldehyde that are adsorbed parallel those present in solution. In particular, the fraction of adsorbed species that is protonated at -0.2 V varies with pH in a manner almost identical with the fraction that is protonated in bulk solution. The protonated compound exists almost completely in the hydrated form (gem-diol) in the interface just as it does in solution. At a given pH, the fraction protonated on the surface increases as …

The Effect Of Solvent Type On The Infrared Spectrum Of Carbon Monoxide Adsorbed On A Platinum Electrode, Stanley Pons, Mark Anderson, Daniel Blackwood

Mark R. Anderson

No abstract is currently available.

A Comprehensive Method To Characterize Mixed Conduction Electrolytes, Michael P. Setter, J. Bruce Wagner Jr.

Michael P. Setter

Determination of the electrical characteristics of an electrolyte is vitally important to the design of battery materials and sensors. A wide variety of parameters are available from both dc and ac measurements. Through the use of computer control and a custom multiplexor, we can perform dc polarization and ac impedance measurements on a sample, without replacing electrodes.