Physical Sciences and Mathematics Commons^™

Thin Polyimide Films Prepared By Ionic Self-Assembly, Mark Anderson, Richey Davis, C. Douglas Taylor, Michiaiah Parker, Spencer Clark, Daniela Marciu, Michael Miller

Mark R. Anderson

Layer-by-layer electrostatic deposition of polyelectrolytes was used to modify a gold substrate with polydiallyl dimethylammonium chloride and an Ultem-type poly(amic acid) salt. Following deposition, heat treatment converted the poly(amic acid) salt into a polyimide. A decrease in the thin film thickness and a substantial increase in the interfacial contact angle accompanied thermal treatment. Results from cyclic voltammetry measurements also show that the imidized surface had a decreased dielectric constant relative to an unmodified or a poly(amic acid)-modified interface. Each of these results is consistent with formation of the polyimide. Infrared spectra of the thin films formed by the electrostatic deposition …

Institutsdagen At The Royal Institute Of Technology, Stockholm, Sweden, May 3, 2000, Otto Vogl, Ann Christine Albertsson

Otto Vogl

No abstract provided.

Automated, Web-Based, Second-Chance Homework, Randall W. Hall, Leslie G. Butler, Saundra Y. Mcguire, Sean P. Mcglynn, Gary L. Lyon, Ron L. Reese, Patrick A. Limbach

Randall W. Hall

Poly Millennial 2000 Hilton Waikoloa Villages, Hawaii, December 9-13, 2000, Otto Vogl, William Daly

Otto Vogl

No abstract provided.

Dopamine Adsorption At Surface Modified Carbon-Fiber Electrodes, Bradley Bath, Heidi Martin, R. Mark Wightman, Mark Anderson

Mark R. Anderson

Fast-scan cyclic voltammetry at high repetition rates was used to characterize adsorptive properties of dopamine (DA) at native and modified carbon-fiber microelectrode surfaces. Disk electrodes were fabricated from Thornel P55 fibers, and cylindrical electrodes, from Thornel T650 fibers. Their surfaces were modified by physisorption of 2,6-anthraquinone disulfonic acid (2,6-AQDS) or chemisorption of 4-carboxyphenyl or catechols. Chemisorption was accomplished via electrochemical reduction of diazonium salts. The degree of DA adsorption and its oxidation kinetics were found to vary for the two types of native carbon fiber electrodes and with the different chemical overlayers on the carbon surfaces. 2,6-AQDS measurably increased DA …

Teaching Analytical Chemistry To The Masses: How We Went From 2 Courses To 7 Courses In 10 Years, Gary Long, Mark Anderson, Brian Tissue, John Morris

Mark R. Anderson

No abstract is currently available.

Interactive Multimedia Over The Internet For Teaching Analytical Chemistry, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Opportunities In Computational Materials Science, Randall Hall, Juana Moreno

Randall W. Hall

The White House Materials Genome Initiative intends to double the speed with which we discover, develop, and manufacture new materials. In order for this initiative to be successful an unprecedented collaboration between computer scientists, applied mathematicians, computational scientists, and engineers with expertise in each of the aspects of the simulation-guided design of modern materials must be established. We must also take advantage of the enormous national investments in the next generation of hyperparallel, heterogeneous, multicore supercomputers to develop experimentally verified algorithms. In this talk I will describe new collaborative efforts in Louisiana towards developing a State-wise team of scientist to …

A Cooperative Molecular Modeling Exercise— The Hypersurface As Classroom, Christopher J. Cramer, Bethany L. Kormos, Paul Winget, Vanessa M. Audette, Jeremy M. Beebe, Carolyn S. Brauer, W.Russ Burdick, Eric W. Cochran, Brian M. Eklov, Timothy J. Giese, Yongseok Jun, Lakshmi S.D. Kesavan, Christopher R. Kinsinger, Mikhail E. Minyaev, Ramkumar Rajamani, Jonathon S. Salsbury, John M. Stubbs, Jack T. Surek, Jason D. Thompson, Vincent A. Voelz, Collin D. Wick, Ling Zhang

Eric W. Cochran

Quantum chemistry has been a staple of undergraduate curricula for several decades. For the most part, however, it has been the rare course in quantum chemistry that advances much beyond the hydrogen atom (or perhaps H2) in terms of describing the electronic structure of real molecular systems. Driven in part by staggering advances in computer technology during the last 15 years or so, which have rendered possible on a laptop calculations that once would have taxed the largest mainframes available, this situation now seems to be changing (1–3).

Live Demonstration Of The Personal Response System: A Tool For Prying Classroom Feedback From Students, Thomas Goyne

Thomas Goyne

No abstract provided.

A Biochemistry Laboratory Course Which Provides A 'Taste Of Research, Thomas Goyne

Thomas Goyne

No abstract provided.

Kinetics Of Substitution Of Weakly Coordinating Nitrate By Chloride In (Η5-Cp)Ru(Co)(Er3)Ono2 (Er3 = Asph3, Pph3, P(P-Anisyl)3, Pph2(O-Anisyl), P(Oph)3) In Dichloromethane., Minhton Cao, Liem Do, Norris Hoffman, Man Lung Kwan, Julie Little, J. Mcgilvray, Christopher Morris, Bjorn Söderberg, Andrzej Wierzbicki, Thomas Cundari, Charles Lake, Edward Valente

Man Lung Desmond Kwan

The d6 complexes of formula (η5-Cp)Ru(CO)(ER3)ONO2, where ER3 = AsPh3, PPh3, P(p-anisyl)3, PPh2(o-anisyl), and P(OPh)3, were prepared by reaction of their chloro analogues with AgNO3 in CH2Cl2. They underwent moderately slow substitution of the relatively weakly coordinating nitrate by chloride in dry CH2Cl2 in the presence of excess [N(PPh3)2+]Cl-. A kinetics study showed the reaction to be first order in nitrato complex and independent of chloride salt concentration under pseudo-first-order conditions. First-order rate constants for nitrate metathesis follow the trend P(OPh)3 < PPh3 < P(p-anisyl)3 < AsPh3 PPh2(o-anisyl), with k1 at 25 °C for the first four in the series from 1.4 to 4.4 × 10-5 s-1. Activation parameters for conversion of (η5-Cp)Ru(CO)(AsPh3)ONO2 to its chloride are ΔH‡ = 17(2) kcal/mol and ΔS‡ = −21(5) eu. Even use of a slightly moist solvent increased the rate of nitrate metathesis by 20−30% without changing the form of the rate law. The complex containing PPh2(o-anisyl) was approximately 2 orders of magnitude more reactive (k1 = 4.9 × 10-3 s-1). A likely explanation is stabilization of a coordinatively unsaturated intermediate by weak coordination of the potentially chelating o-OMe group. A mechanism entailing rate-limiting conversion of the neutral nitrato complex into a coordinatively unsaturated ion-paired species is consistent with this set of data. Semiempirical calculations (PM3(tm)), which model the structures of complexes in these systems quite well, supported such behavior. X-ray crystal structures were determined for the AsPh3 nitrato and chloro complexes and for the PPh3 chloro complex.

Spectra And Geometries Of Ar+ N (N = 30 - 60) [Invited], Jose Gascon, Randall W. Hall

Randall W. Hall

Stereoselective One-Pot Synthesis Of Vinylsilanes From Aromatic Aldehydes, Man Lung Kwan, Chiu Yeung, Kerry Breno, Kenneth Doxsee

Man Lung Desmond Kwan

Vinylsilanes serve as convenient vinyl anion equivalents, but procedures for their stereoselective synthesis from aldehydes are scarce. A variety of aromatic aldehydes are converted to the corresponding vinylsilanes in a one-pot procedure involving the addition of (trimethylsilylmethyl)lithium to the aldehyde followed by treatment with Cp2TiCH2·AlMe2Cl (‘Tebbe's reagent’). Halide and alkoxide substituents are tolerated, and (E)-vinylsilanes are formed exclusively in good yield.

Simple Relationships For The Estimation Of Melting Temperatures Of Homologous Series, James S. Chickos, Gary Nichols

James Chickos

No abstract provided.

Dispersion Of Potassium Nitrate And The Resulting Strong Basicity On Zirconia, Ying Wang, Wenyu Huang, Yuan Chun, Jia Rong Xia, Jian Hua Zhu

Wenyu Huang

A novel solid superbase is derived from zirconia-supported potassium nitrate. Dispersion and decomposition of potassium nitrate on zirconia were investigated and compared with that on alumina to explore the effect of the support on the preparation of solid strong bases. Spontaneous dispersion capacity of KNO3 on ZrO2 was found to be 8.1 K+ nm-2, very close to that of a vacant site on ZrO2. An unusually strong basicity was generated on ZrO2 through decomposition of the loaded KNO3 that began around 613 K, enhancing the catalytic activity of ZrO2 in cis-but-2-ene isomerization at 273 K. Moreover, KNO3/ZrO2 samples, except 34% …

Synthesis And Characterization Of Potassium-Modified Alumina Superbases, Ying Wang, Jian Hua Zhu, Wenyu Huang

Wenyu Huang

Novel solid superbases can be prepared by dispersing potassium salts such as K2CO3 and KHCO3 on alumina followed by thermal treatments. The resulting materials show an extremely high activity in the isomerization of cis-but-2-ene at 0°C and possess base strength of at least H− = + 26.5. X-Ray diffraction (XRD) and Raman spectra of K2CO3 or KHCO3 modified alumina reveal the formation of potassium hydroalumina carbonate, which is the precursor of active species. Decomposition of potassium salts on alumina has been studied by use of thermal gravimetric differential thermal analysis (TG-DTA) and temperature programmed decomposition-mass spectrometry (TPDE-MS). Two CO2 evolution …

Propagating Conformational Changes Over Long (And Short) Distances In Proteins, Edward Yu, Daniel E. Koshland Jr.

Edward Yu

The problem of the propagation of conformational changes over long distances or through a closely packed protein is shown to fit a model of a ligand-induced conformational change between two protein states selected by evolution. Moreover, the kinetics of the pathway between these states is also selected so that the energy of ligand binding and the speed of the transition between conformational states are physiologically appropriate. The crystallographic data of a wild-type aspartate receptor that has negative cooperativity and a mutant that has no cooperativity but has native transmembrane signaling are shown to support this model.

4. Bengt Rånby (1920-2000), Otto Vogl, Gerald S. Kirshenbaum

Otto Vogl

No abstract provided.

Formation Of Aryl-Nitrogen Bonds Using A Soluble Copper(I) Catalyst, Dhandapani Venkataraman

Dhandapani Venkataraman

No abstract provided.

Optical Bleaching In Continuous Laser Excited Photothermal Lens Spectrometry, Agnes Chartier, Stephen E. Bialkowski

Stephen E. Bialkowski

This paper presents methods for measuring and modeling optical bleaching that occurs, by using continuous laser sources for solution-phase organic dye molecule spectrometry. Photothermal lens experiments are used to measure the nonlinear optical absorption coefficients of eosin Y, erythrosin B, and pseudo-isocyanine iodide dyes in ethanol as a function of excitation irradiance. Excitation irradiance-dependent photothermal lens data are subsequently interpreted in terms of the photophysics and excited-state relaxation dynamics of the condensed-phase dye molecules under study. The model uses first-order kinetics for excitation and subsequent metastable-state relaxation back to the ground state and accounts for both ground- and metastable-state absorption. …

Using Flash Animation And Streaming Video For Laboratory/Lecture Demonstrations In Large Enrollment Courses, Mark Anderson

Mark R. Anderson

No abstract is currently available.

Metal Binding Studies With Macrocyclic Hexathioethers: Transition Metal Complexes Of 22s6 And 20s6”,, Gregory Grant, Christopher Brandow, Chrystal Bruce, Mark Brandt, Rebecca Kirk, Sabrina Lee, Kerry Robinson, Larry Mehne

Chrystal D. Bruce

No abstract provided.

Structural Characterization Of Mao And Related Aluminum Complexes. 1. Solid-State 27al Nmr With Comparison To Efg Tensors From Ab Initio Molecular Orbital Calculations, Pamela L. Bryant, Chris R. Harwell, Anthony A. Mrse, Earl F. Emery, Zhehong Gan, Tod Caldwell, Arneil P. Reyes, Philip Kuhns, David W. Hoyt, Larry S. Simeral, Randall W. Hall, Leslie G. Butler

Randall W. Hall

The Discovery-Oriented Approach To Organic Chemistry. 5. Stereochemistry Of E2 Elimination: Elimination Of Cis- And Trans-2-Methylcyclohexyl Tosylate, Ram S. Mohan, Marcus E. Cabay, Brad J. Ettlie, Adam J. Tuite, Kurt A. Welday

Ram S. Mohan

Deprotection Of Ketoximes Using Bismuth(Iii) Nitrate Pentahydrate, Ram S. Mohan, Bryce A. Nattier, Kyle J. Eash

Ram S. Mohan

The Discovery-Oriented Approach To Organic Chemistry. 4. Epoxidation Of P-Methoxy-Trans-Β-Methylstyrene. An Exercise In 1H Nmr And 13C Nmr Spectroscopy For Sophomore Organic Laboratories, Ram S. Mohan, Rebecca S. Centko

Ram S. Mohan

A Facile And Efficient Method For The Rearrangement Of Aryl-Substituted Epoxides To Aldehydes And Ketones Using Bismuth Triflate, Ram S. Mohan, Kaushik A. Bhatia, Kyle J. Eash, Nicholas M. Leonard, Matthew C. Oswald

Ram S. Mohan

An Efficient Method For The Chemoselective Synthesis Of Acylals From Aromatic Aldehydes Using Bismuth Triflate, Ram S. Mohan, Marc D. Carrigan, Kyle J. Eash, Matthew C. Oswald

Ram S. Mohan