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Structure Of 2-Methyl-5,6,7-Triphenyl-6,7-Dihydropyrazolo[2,3-A]Pyrimidine, Sergey V. Lindeman, Yuri T. Struchkov, O. V. Shishkin, S. M. Desenko, V. V. Lipson, V. D. Orlov

Chemistry Faculty Research and Publications

C₂₅H₂₁N₃, M_r = 363.46, monoclinic, P2₁/n, a = 9.245 (2), b = 23.502 (5), c = 9.340 (2) Å, β= 103.50(3)°, V=1973.3(2) ų, Z=4, D_x= 1.220 (2) g cm^-3, λ (Mo Kα )= 0.71069 Å, μ = 0.068 cm^-1, F(000) = 768, T= 292 K, R = 0.091 for 1442 unique observed reflections. The dihydropyrimidine ring adopts a distorted sofa conformation. The aryl substituents on the saturated C atoms have an axial orientation.

Pairwise And Many-Body Contributions To Interaction Potentials In He(N) Clusters, Carol A. Parish, Clifford E. Dykstra

Chemistry Faculty Publications

High level ab initio calculations have been carried out to assess the pairwise additivity of potentials in the attractive or well regions of the potential surfaces of clusters of helium atoms. A large basis set was employed and calculations were done at the Brueckner orbital coupled cluster level. Differences between calculated potentials for several interacting atoms and the corresponding summed pair potentials reveal the three‐body and certain higher order contributions to the interaction strengths. Attraction between rare gas atoms develops from dispersion, and so helium clusters provide the most workable systems for analyzing nonadditivity of dispersion. The results indicate that …

Enantiomeric Separation Of Chiral Components Reported To Be In Coffee, Tea, Or Cocoa, Apryll M. Stalcup, K. Helen Ekborg, Mary P. Gasper, Daniel W. Armstrong

Chemistry Faculty Research & Creative Works

Literally hundreds of volatile compounds have been identified in coffee, tea, and cocoa. A significant proportion of these compounds are known to be chiral. The enantiomeric composition of most of these compounds is unknown, and until recently there were no efficient analytical procedures for their identification. The advent of cyclodextrin-based chiral stationary phases for capillary gas chromatography provides effective means for the enantioselectivity analysis of many of these compounds. Some of these are known to be flavor and fragrance components that occur naturally or are produced from the manufacturing process (e.g., fermentation, drying, and roasting). © 1993, American Chemical Society. …

Tetrabutylammonium Benzoate‐Initiated Polymerization Of Propylene Oxide, Xuemin Chen, Michael R. Van De Mark

Chemistry Faculty Research & Creative Works

The polymerization of propylene oxide by the benzoate anion was aided through the use of the tetrabutylammonium counterion. The effect of the tetrabutylammonium ion was to increase the solubility of the salt and to increase the ion separation. The polymerization was carried out in a pressure reactor at temperatures from 40 to 108°C, producing polymer yields of 2–78%. The study addressed the general effects of solvent, temperature, and ratio of initiator to monomer. © 1993 John Wiley & Sons, Inc. Copyright © 1993 John Wiley & Sons, Inc.

Mechanistic Studies On The Preparation Of The Hantzsch’S Base From Ethyl Acetoacetate And Chloromethylmethyl Ether, Huo-Jin Hsieh

Dissertations and Theses @ UNI

Dihydropyridines, which were first studied by Hantzsch in 1882, now bear his name. A new synthesis of Hantzsch 's base, 2,6-dimethyl-3,5-dicarboethoxy-l ,4- dihydropyridine (lb), was discovered. The preparation of Hantzsch's base (lb) from new starting materials, ethyl acetoacetate (3) and chloromethylmethyl ether (4), was described. Ethyl acetoacetate was reacted with sodium amide in liquid ammonia followed by chloromethylmethyl ether to form the 2,6-dimethyl-3,5-dicarboethoxy1,4-dihydropyridine (lb) in 84% overall yield. Compound (lb) was further identified by its oxidation to the corresponding pyridine, 2,6-dimethyl-3,5-dicarboethoxypyridine ( 11 b) by glacial acetic acid. A mechanism for the formation of the compound ( 1 b) was …

Self-Diffusion Studies In Polymer-Solvent Systems By Pulsed-Gradient Spin-Echo Nuclear Magnetic Resonance, R. Allen Waggoner

Doctoral Dissertations

"Pulsed gradient NMR techniques have been used to study self-diffusion in polymer solutions. The systems studied include toluene, cyclohexane, ethylbenzene, chloroform, t-butyl acetate, and methyl ethyl ketone in polystyrene; methyl methacrylate in poly(methyl methacrylate); poly(ethylene oxide) in water; and water in biological tissue. The polymer diffusion data are evaluated in terms of scaling theory as they relate to the scaling of the polymer diffusion coefficient with molecular weight. The solvent diffusion data are evaluated with kinetic and free-volume theories. In addition a relatively simple dependence of diffusion coefficient on polymer volume fraction is derived from free-volume theory. The solvent diffusion …

Nuclear Magnetic Resonance Study Of Antigen-Antibody Complexes, Including Sequence Specific Assignments And Structural Analysis Of Neurophysin As An Antigen Model, Elisar Jamil Barbar

Dissertations and Theses

The interaction between molecules is essential in a wide range of biological processes. A detailed knowledge of these interactions is necessary for understanding these processes. Among the systems that involve important interactions is the immune system. NMR spectroscopy has a large number of spectral parameters that were used in this work to study antibody-antigen interactions. These same parameters were also used to begin a structural analysis of a medium-sized protein, neurophysin, that has important interactions with neurohormones, and served here as a model antigen. A set of ligands differing in size and charge was designed and used to probe the …

Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part 1: Kinetics Of Carbon Formation, L.L. Mkayula

Tanzania Journal of Science

Carbon formation on an Esso reforming type catalyst Pt/γ-A1₂O₃ by C₃ and C₄ hydrocarbons has been studied at atmospheric pressure and within a temperature range of 450-600⁰C using a microbalance capable of detecting up to 10^-6 g by weight of coke. A kinetic model initially developed by Froment has been used to analyze the transient regime of coke versus time curves. Deactivation function-reaction mechanism relations have been proposed and applied to the coking results. Carbon deposition rates are highly dependent on temperature, partial pressures of reactant, nature and composition of reactions, and …

Behavior Of Chlorine & Sulfur During Coal Pyrolysis & Combustion, Dakang Shao

Masters Theses & Specialist Projects

The behavior of chlorine and sulfur in Illinois coals and during pyrolysis and combustion their forms in the coals were evaluated by combined Thermogravimetry/Fourier Transform Infrared Spectroscopy/ Ion Chromatography (TG/FTIR/IC) techniques. It was found that more than 90% of chlorine in Illinois coals was liberated as HC1 gas during pyrolysis and combustion in the temperature range of approximately 3000 - 600°C, with the amount reaching the maximum around 440°C. Similarity of the HC1 and NH3 release profiles during pyrolysis of IBC-109 indicates that the forms of chlorine in coal is associated closely with the forms of nitrogen, and that the …

Computational Neural Networks In Chemistry: Model Free Mapping Devices For Predicting Chemical Reactivity From Molecular Structure, David Wayne Elrod

Dissertations

Computational neural networks (CNNs) are a computational paradigm inspired by the brain’s massively parallel network of highly interconnected neurons. The power of computational neural networks derives not so much from their ability to model the brain as from their ability to learn by example and to map highly complex, nonlinear functions, without the need to explicitly specify the functional relationship. Two central questions about CNNs were investigated in the context of predicting chemical reactions: (1) the mapping properties of neural networks and (2) the representation of chemical information for use in CNNs.

Chemical reactivity is here considered an example of …

Synthesis Of Symmetric And "Mixed-Ligand" Homocyclopentadienyl Ruthenocenes, John Adjeiku Amanfu

Masters Theses

No abstract provided.

Surface Carbon Formation On Pt/ˠ-A12o3 From C3 And C4 Hydrocarbons Part Ii: Characterization Of Coked Samples, L.L. Mkayula

Tanzania Journal of Science

The total surface area, pore size distribution, metal surface area, particle size and topography of coked Pt/γ-1₂O₃ catalyst samples used in in part 1 of this series were measured and compared with those of a fresh catalyst. No significant changes in total surface areas of the coked catalyst was observed despite a high coke content in some samples. This is interpreted in terms of partial narrowing of mesopores that was confirmed by pore size distributions observations of high temperature coked samples. The platinum metal surface area of high temperature coked catalysts decreased with increase in temperature and …

A Preliminary Chemical Survey Of The Salt Deposits And Evaporates Of Lake Balangida, Hanang District, Tanzania, N. Mwakoba, D. Mosha, K. Schrøder

Tanzania Journal of Science

Lake Balangida is a typical salt-and –soda lake sharing many common hydrochemical features with the twenty or so hypersaline dischargeless lake of the African Gregory Rift Valley (Dead Sea to Lake Malawi). Sulphate content is however, comparatively exceptionally high but the single most contrasting dissimilarity is the virtual absence of fluoride. In previous reports, we have presented findings on the chemistry of the lake brines and inflows. In the present work, the salt deposits and evaporated which cover the lake after desiccation during the September-December dry spell are chemically examined. Salt and soda appear to occur in separate locations; the …

Viscosities Of Vegetable Oils And Fatty Acids, Hossein Noureddini, B. C. Teoh, L. Davis Clements

Papers in Biomaterials

Data for viscosity as a function of temperature from 24 to 110°C (75 to 230°F) have been measured for a number of vegetable oils (crambe, rapeseed, corn, soybean, milk- coconut, lesquerella) and eight fatty acids in the from Cg to CZZ The viscosity measurements were performed according to ASTM test methods D 445 and D 446. Several correlations were fitted to the experimental data. Correlation constants for the best fit are presented. The range of temperature in which the correlations are valid is from 24°C (75°F), or the melting point of the substance, to 110°C (230°F). The correlation constants are …

Dynamic Nmr Study Of Bond Rotational Activation Parameters In Micelles, Dietmar A. Leitner

Dissertations and Theses

The behavior of surfactants in solution has been and still is of scientific, technological, and industrial interest. The micelle forming compounds sodium N-( octyloxycarbonyl)sarcosinate (NaOcSarc), and sodium N-(decyloxycarbonyl)sarcosinate (NaDecSarc) show in aqueous solution two ¹H NMR N-methyl peaks arising from a possible cis- or trans-conformation. The relative population of the N-methyl peaks depends mostly on the concentration of surfactant indicating micelle formation. Upon heating the two peaks start to coalesce and finally appear as one single peak. The temperature range in which this phenomenon occurs is from 25°C to 65°C. The primary interest of this study was to determine …

Identification Of The Nd Δ And Σ States And The 1,3Φ←←X  3Σ− G Transition Of O2 By Resonant Multiphoton Ionization, Robert J. Yokelson, R. J. Lipert, W. A. Chupka

Chemistry and Biochemistry Faculty Publications

Spectra of the 3dRydberg state region of O₂ have been obtained by two‐photon resonant ionization of the ground electronic state. By varying the rotational distribution and radiation polarization, all observed bands were identified and attributed to excitation of Σ, Δ, and Φ states. Earlier assignments were corrected. The Δ and Φ assignments are complete while the Σ assignments are so far incomplete.

Identification Of The Ns And Nd Rydberg States Of O2 For N=3–5, Robert J. Yokelson, R. J. Lipert, W. A. Chupka

Chemistry and Biochemistry Faculty Publications

The 4s‐3d and 5s‐4dRydberg complexes of diatomic oxygen have been studied by (2+1) resonance‐enhanced multiphoton ionization of the X  ³∑ _g ⁻ ground state of O₂. We have located and identified at least two vibrational levels of each of the following states: Three of four expected 4sσ Π states; all four expected 5sσ Π states; 18 of 22 expected 3d states (with only the states of the 3dσ orbital remaining unobserved); and 5 of the 10 predicted 4dπ states. State assignments …

Fragment Rotational State Distributions From The Dissociation Of Neibr: Experimental And Theoretical Results, Thomas Alex Stephenson

Chemistry & Biochemistry Faculty Works

The IBr fragment rotational state distributions that result when the NeIBr van der Waals molecule undergoes vibrational predissociation have been measured in a pump-probe laser-induced fluorescence experiment. Independent of initial vibrational state and the number of quanta of vibrational energy lost from the I-Br coordinate, the rotational distributions extend over the full range of energetically accessible states. From the observation of energetic constraints on the rotational distribution, the dissociation energy (D0) is calculated to be 65.5 +/- 1.2 cm-1 for the A electronic state, v=16. For the X electronic state, v=0, D0=71.8 +/- 1.2 cm-1. Quantum mechanical bound state calculations …

A Mössbauer Effect Study Of The Microscopic Magnetic Properties Of Nd₂Fe₁₇ And Nd₂Fe₁₇N₂.₆, Gary J. Long, Oran Allan Pringle, Fernande Grandjean, K. H. J. Buschow

Chemistry Faculty Research & Creative Works

The Mössbauer spectra of Nd₂Fe₁₇ and Nd ₂Fe₁₇N_2.6 have been measured at various temperatures between 78 and 295 K and analyzed with a model that is based on the Wigner-Seitz cell environment of each iron site, the orientation of the magnetization, and the magnetic moments as determined from either neutron-diffraction measurements or band-structure calculations. Upon nitrogenation of Nd₂Fe₁₇, the weighted average isomer shift increases from 0.060 to 0.164 mm/s and further the isomer shifts of the four crystallographically distinct sites increase in agreement with the increase observed in their …

Synthesis Of Bisphenol A Bis-2-Hydroxypropylmethacrylate (Bisgma) And Diethylchlorophosphate And 2-Hydroxyethylmethacrylate (Decp-Hema) And Preparation Of Dental Adhesives, Da Xie

Theses

BisGMA and DECP-HEMA were separately synthesized from Bisphenol A and glycidyl methacrylate and from diethylchlorophosphate and 2-hydroxyethyl-methacrylate. The structure of the monomer, BisGMA, was further analyzed by means of chromatography, VPO, IR, FTIR and GC-MASS.

Based on the main monomers, BisGMA, DECP-HEMA and an organosilane compound, a dental adhesive has been formulated. Although the tervile strength of the adhesive has been found to be not as good as the adhesive formulated by a previous worker (student), its applicability to teeth is more suitable for clinic practice.

Use Of High-Energy Radiation For Degradation Of Environmental Pollutants, Robert D. Guthrie, Manjiri Patwardhan

KWRRI Research Reports

The purpose of this project was to explore the advantages and/or limitations of high-energy radiation treatment as a method for degrading organic pollutants, particularly aryl halides, in an aqueous medium. We have done analyses of ⁶⁰Co-irradiated samples and kinetic studies using pulsed electron beams. For aryl halides containing no more than two fused rings, the main products detected are those of simple halogen replacement by hydrogen, although the amount of aryl halide destroyed was always greater than the total amount of products detected. To accomplish halogen replacement by H, the reaction solvent may not be pure water but must …

Interferences Of N-Chloroorganic Compounds In Free Chlorine Determination, Sushma H. Gandhi

Chemistry & Biochemistry Theses & Dissertations

Various N-chlorinated organic compounds give positive responses to the analytical methods used to determine free chlorine. The present work quantifies interferences due to N-chloroisoleucine, N-chloropiperidine and N-chloro-2-methylbutyraldiminein the free chlorine determination by amperometry. These N-chloroorganic compounds were also studied for the recovery in response by the indicator electrode in amperometric titrimetry. The total chlorine content of the chloroaldimines derived from the chlorination of the amino acids, alanine, glutamic acid, glycine, isoleucine, leucine, phenylalanine, serine, valine, and those of dipeptides, alanylvaline and glycylleucine, was determined by amperometry and DPD-FAS titrimetry. The two methods were compared and evaluated with respect to recovery …

Nio(100) Valence-Band Density Of States During Hydrogen Reduction , K.W. Wulser, B.P. Hearty, Marjorie Langell

Marjorie A. Langell Publications

Photoelectron spectroscopy with incident photons of 40–120 eV has been used to determine the valence-band structure of NiO(100) as the surface undergoes slow hydrogen reduction. Low pressure and moderate temperature conditions (1.3×10^-2 Pa and 625 K) allow oxygen to be removed from the near-surface region with a minimal disruption in the NiO(100) substrate. Both NiO(100) ultraviolet photoemission spectroscopy (UPS) and low-energy electron-diffraction features persist at NiO(100) reduced surfaces throughout the reduction process. In addition, reduced nickel features slowly grow into the UP spectra, with the most intense peak found in the NiO band gap. Chemisorbed hydrogen, hydroxyls, and oxygen …

The Immunosuppressive And Toxic Effects Of Fk-506 Are Mechanistically Related: Pharmacology Of A Novel Antagonist Of Fk-506 And Rapamycin, Francis J. Dumont, Mary Jo Staruch, Samuel L. Koprak, John Siekierka, C. Shirley Lin, Richard Harrison, Tonya Sewell, Victoria M. Kindt, Thomas R. Beattie, Matthew Wyvratt, Nolan H. Sigal

Department of Chemistry and Biochemistry Faculty Scholarship and Creative Works

FK-506 inhibits Ca2+-dependent transcription of lymphokine genes in T cells, and thereby acts as a powerful immunosuppressant. However, its potential therapeutic applications may be seriously limited by several side effects, including nephrotoxicity and neurotoxicity. At present, it is unclear whether these immunosuppressive and toxic effects result from interference with rehted biochemical processes. FK-506 is known to interact with FK-binding protein-12 (FKBP-12), an abundant cytosolic protein with cis.trans peptidyl-prolyl isomerase activity (PPlase) activity. Because rapamycin (RAP) similarly binds to FKBP-12, although it acts in a manner different from FK-506, by inhibiting T cell responses to lymphokines, such an interaction with FKBP-12 …

Drying Of Beulah-Zap Lignite, Karl S. Vorres, David L. Wertz, Vivak Malhotra, Yuhong Dang, J.T. Joseph, Ronald Fisher

Faculty Publications

Lignite dried in a stream of dry nitrogen at moderate temperatures (20-80-degrees-C) loses water in two distinguishable modes. The first mode represents about 80-85% of the loss of moisture. The second represents the other 15-20% lost under these conditions. The rate follows a unimolecular mechanism (like radioactive decay) for each mode. The activation energy for the first mode is close to the heat of vaporization of water. The rate is dependent upon the gas flow around the sample and the weight (or thickness) of the sample. Work at Amoco Oil Company indicated that the oil yield was higher for the …

34th Rocky Mountain Conference On Applied Spectroscopy

Rocky Mountain Conference on Magnetic Resonance

Program and registration information for the 34th annual meeting of the Rocky Mountain Conference on Applied Spectroscopy, co-sponsored by the Colorado Section of the American Chemical Society and the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 2-6, 1992.

Development Of Membrane Film Fiber Optic Based Sensors For The Remote Monitoring Of The Quality Of Surface And Groundwater, Leonidas G. Bachas

KWRRI Research Reports

The objective of this study was the development of chromo- and fluoroionophores and their subsequent use in sensors capable of surface and groundwater monitoring. Several reagents (modified crown ethers and porphyrins) were synthesized based on principles of chemical recognition and used for metal and pH sensing. The modified crown ether reagents include a chromogenic or fluorogenic group. The selectivity of these reagents is controlled by the size of the crown ether ring and the type of the chromogenic or fluorogenic side-arm. In addition, a fluorogenic crown ether was synthesized that incorporates a fluorogenic side-arm and a perfluorinated carbon chain. The …

Dispiro- 1,2,4,5-Tetraoxanes: A New Class Of Antimalarial Peroxides, Jonathan L. Vennerstrom, Hong-Ning Fu, Walter Reed Army Institute Of Research, Arba L. Ager Jr., James K. Wood

Chemistry Faculty Publications

Dispiro-l,2,4,5tetraoxanes2 -4 were synthesized as potential peroxide a n t h a l a* d drugs. They had curative activity against Plasmodium berghei in vivo at single doses of 320 and 640 mg/kg which confirms earlier unpublished data Moreover, artemisinin (1) and 4 had equivalent ED”s against P. berghei in vivo in the multiple-dose Thompson tat; neither showed any evidence of acute toxicity at total doses of more than 12 g/kg. Dispiro-l,2,4,5-tetraoxane 4 had IC₅₀’s comparable to those of 1 against Plasmodium falciparum clones in vitro. These results confirm the potential of dispiro-l,2,4,5-tetraoxanes as a new class of …

Nmr Analysis Of Sulfur Compounds In Petroleum, Kanning Wu

Masters Theses & Specialist Projects

The speciation and quantification of organic sulfur forms in fossil fuel is an area of research. This thesis describes an NMR method which offers potential for identifying and possibly quantifying both nonvolatile and volatile sulfur forms in fossil fuels. The method is based on the methylation of sulfur compounds to form methyl sulfonium salts:

RSR + Ch₃I --> (R₂S+-Ch₃)I^~

We propose to apply this chemistry to the analysis of sulfur functions in fossil fuels. The sulfur functions are methylated using ¹³C-enriched methyl iodide. The products are then analyzed by ¹³C NMR …

Investigation Of Alignment Dynamics In Mg-Ne And Mg-Ar Two-Photon Fractional Collisions, David Allen Olsgaard

Physics Theses & Dissertations

A new technique is used to observe the dynamics of electronic alignment in a dissociating collision complex. The technique requires the absorption of two optical photons during a single binary collision. Two exciting light fields are tuned into the wings of the 3s¹s₀-3p₁ and 3p¹p₁-5s¹s₀ resonances of Mg where strong collisions with rare gas atoms induce transitions between corresponding molecular states. The alignment produced in the intermediate state by the first excitation is probed by the second laser as a function of relative linear laser polarization and laser …