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Full-Text Articles in Chemistry
A Bond Length – Bond Valence Relationship For Carbon – Nitrogen Bonds, C. Harris, F. D. Hardcastle
A Bond Length – Bond Valence Relationship For Carbon – Nitrogen Bonds, C. Harris, F. D. Hardcastle
Journal of the Arkansas Academy of Science
In a recent study, Pauling’s relationship between bond length and valence was derived along with a definition for his fitting parameter b that incorporates the orbital exponents for each atom contributing to the bond of interest. The values of b for various bonds, including C-N bonds, were calculated using the orbital exponent data. In this study, Pauling’s correlation between bond length and bond valence, as well as his valence sum rule, were used with the recently-derived definition for b in order to produce a relationship specifically applicable to C-N bonds. The resulting equation was checked against published x-ray diffraction data …
A General Valence-Length Correlation For Determining Bond Orders: Application To Carbon-Carbon And Carbon-Hydrogen Chemical Bonds, F. D. Hardcastle
A General Valence-Length Correlation For Determining Bond Orders: Application To Carbon-Carbon And Carbon-Hydrogen Chemical Bonds, F. D. Hardcastle
Journal of the Arkansas Academy of Science
A quantum-mechanical LCAO approach was used to derive Pauling’s popular empirical bond valencelength relationship s = exp((R₀-R)/b), where s is the bond order or bond valence associated with bond length R, and R₀ and b are fitting parameters. An expression for the b “empirical” fitting parameter is derived in terms of atomic orbital exponents. The b parameters calculated from the atomic orbital exponents are consistent with optimized b parameters. In general, atomic orbital exponents may be used to determine bond valence-length relationships for any chemical bond regardless of valence state, oxidation number, physical or chemical environment. In this study, almost …
Wave Profile For Anti-Force Waves With Maximum Possible Currents, M. Hemmati, R. Horn, W. P. Childs, A. K. Meredith
Wave Profile For Anti-Force Waves With Maximum Possible Currents, M. Hemmati, R. Horn, W. P. Childs, A. K. Meredith
Journal of the Arkansas Academy of Science
In the theoretical investigation of the electrical breakdown of a gas, we apply a one-dimensional, steady state, constant velocity, three component fluid model and consider the electrons to be the main element in propagation of the wave. The electron gas temperature, and therefore the electron gas partial pressure, is considered to be large enough to provide the driving force. The wave is considered to have a shock front, followed by a thin dynamical transition region. Our set of electron fluid-dynamical equations consists of the equations of conservation of mass, momentum, and energy, plus the Poisson's equation. The set of equations …
Bond Length - Bond Valence Relationships For Carbon - Carbon And Carbon - Oxygen Bonds, C. Harris, F. D. Hardcastle
Bond Length - Bond Valence Relationships For Carbon - Carbon And Carbon - Oxygen Bonds, C. Harris, F. D. Hardcastle
Journal of the Arkansas Academy of Science
In the present study, relationships are developed for determining bond orders (also referred to as bond valences or bond numbers) from published bond lengths for carbon-carbon (C-C) and carbon-oxygen (C-O) bonds. The relationships are based on Pauling’s empirical formula s = exp((Ro-R)/b)), where s is the bond order, R is the corresponding bond length, Ro is the unit valence bond length, and b is a fitting parameter. We use a recently derived relationship for the b parameter in terms of the bonding atoms’ published atomic orbital exponents. The resulting equations were checked against published x-ray diffraction (XRD) data for 176 …
Low-Level Mercury Causes Inappropriate Activation In T And B Lymphocytes In The Absence Of Antigen Stimulation, K. L. Weigand, J. L. Reno, B. M. Rowley
Low-Level Mercury Causes Inappropriate Activation In T And B Lymphocytes In The Absence Of Antigen Stimulation, K. L. Weigand, J. L. Reno, B. M. Rowley
Journal of the Arkansas Academy of Science
The immune system primarily utilizes two cell types for adaptive immunity: T lymphocytes and B lymphocytes. T lymphocytes are activated when antigen presenting cells (APCs) present antigen to membrane-bound T cell receptors. B lymphocytes are activated when an antigen binds to receptors embedded in the plasma membrane. In both T and B cells this antigen binding crosslinks the receptor complexes and initiates the signal transduction cascade. These cascades frequently consist of a series of intracellular molecules becoming phosphorylated in a step-wise fashion. Once activated, these cells differentiate into effector cells that clear out the stimulating antigen. Mercury, which is a …
Low Speed Current Bearing Anti-Force Waves, M. Hemmati, W. P. Childs, H. Shojaei, H. Morris
Low Speed Current Bearing Anti-Force Waves, M. Hemmati, W. P. Childs, H. Shojaei, H. Morris
Journal of the Arkansas Academy of Science
For theoretical investigation of electrical breakdown of a gas, we apply a one-dimensional, steady profile, constant velocity, three-component (electrons, ions and neutral particles) fluid model. Our fluid model consists of the equations of conservation of mass, momentum and energy, coupled with the Poison’s equation. The set of equations is referred to as the electron fluid dynamical equations (EFD). This investigation involves breakdown waves with a substantial current behind the wave front, and waves for which the electric field force on electrons is in the opposite direction of the wave propagation (anti-force waves – lightning return stroke). Therefore, the set of …
Wave Profile For Current Bearing Antiforce Waves, H. Morris, W. Childs, P. Pinkston, M. Hemmati, J. Christensen
Wave Profile For Current Bearing Antiforce Waves, H. Morris, W. Childs, P. Pinkston, M. Hemmati, J. Christensen
Journal of the Arkansas Academy of Science
For fluid dynamical analysis of breakdown waves, we employ a one-dimensional, three-component (electrons, ions and neutral particles) fluid model to describe a steady-state, ionizing wave propagating counter to strong electric fields. The electron gas temperature and therefore the electron fluid pressure is assumed to be large enough to sustain the wave motion down the discharge tube. Such waves are referred to as antiforce waves. The complete set of equations describing such waves consists of the equations of conservation of mass, momentum and energy coupled with Poisson’s equation. Inclusion of current behind the wave front alters the set of electron fluid …
Microwave Assisted Synthesis Of Chloropentahaptocyclopentadienediphenylphosphinoethaneruthenium(Ii), S. Muthyala, Mark Draganjac
Microwave Assisted Synthesis Of Chloropentahaptocyclopentadienediphenylphosphinoethaneruthenium(Ii), S. Muthyala, Mark Draganjac
Journal of the Arkansas Academy of Science
No abstract provided.
Molecular Structure Of Pentahaptocyclopentadienebis (Tetrahydrothiophene) Triphenylphosphineruthenium(Ii) Triflate, Paul M. Nave, Mark Draganjac, A. W. Cordes
Molecular Structure Of Pentahaptocyclopentadienebis (Tetrahydrothiophene) Triphenylphosphineruthenium(Ii) Triflate, Paul M. Nave, Mark Draganjac, A. W. Cordes
Journal of the Arkansas Academy of Science
No abstract provided.
Synthesis, Characterization, And Properties Of Homometallic Dinuclear Ruthenium Complex Containing Chloro-Phenanthroline And Bipyridine, A. A. Bhuiyan, S. Kudo
Synthesis, Characterization, And Properties Of Homometallic Dinuclear Ruthenium Complex Containing Chloro-Phenanthroline And Bipyridine, A. A. Bhuiyan, S. Kudo
Journal of the Arkansas Academy of Science
This paper deals with the synthesis and spectroscopic investigation of homometallic dinuclear ruthenium(II) complex containing chlorophenanthroline and bipyridine ligands. This bimetallic ruthenium polypyridine complex may be useful for biological electron transfer studies. Heteroleptic ruthenium monomer complex Ru(bpy)2(Cl-phen) (where bpy = 2,2’-bipyridine and Cl-phen = 5-chloro- 1,10-phenanthroline) was prepared in a two step procedure previously developed in our laboratory. This monomer complex was used to prepare the ruthenium dimer complex, (bpy)2Ru(phen-phen)Ru(bpy)2, by utilizing the Ni-catalyzed coupling reaction. Both the complexes were purified by column chromatography. The identity and the integrity of the complexes were confirmed by elemental analysis as well as …
Density Functional Studies Of The Structure And Bonding In Piano Stool Carbene Complexes, John P. Graham, Robbie Davis
Density Functional Studies Of The Structure And Bonding In Piano Stool Carbene Complexes, John P. Graham, Robbie Davis
Journal of the Arkansas Academy of Science
No abstract provided.
Studies Of Zeolite Entrapped Ruthenium Polypyridine Complexes, Anwar A. Bhuiyan
Studies Of Zeolite Entrapped Ruthenium Polypyridine Complexes, Anwar A. Bhuiyan
Journal of the Arkansas Academy of Science
There is an intense interest in designing molecular systems which will absorb visible sunlight, initiate an electron transfer process, and ultimately convert the solar energy to useful chemical energy of fuels such as hydrogen produced from water. The zeolite-entrapped polypyridine complexes of divalent ruthenium hold promise as efficient photocatalysts for net charge separation and such efficiencies are further enhanced by organized incorporation of donor and acceptor components. This paper deals with the synthesis and spectroscopic investigation of zeolite-entrapped ruthenium polypyridine complexes which may be useful in the development of solar energy conversion schemes. The sensitizer molecules, such as Ru(bpy)3 2+ …
Solid Phase Extraction Of Pesticides With Determination By Gas Chromatography, Anwar A. Bhuiyan, Harry O. Brotherton
Solid Phase Extraction Of Pesticides With Determination By Gas Chromatography, Anwar A. Bhuiyan, Harry O. Brotherton
Journal of the Arkansas Academy of Science
A simple, rapid, and effective method for the extraction of fifteen organochlorine and organophosphorus pesticides based on the use of solid phase Bond Elut C-18 cartridges was studied as an alternative method to those based on extraction with organic solvents. Solid phase extraction is an attractive chromatographic sample preparation technology that reduces analysis time, costs, labor, and solvent consumption relative to traditional liquid/liquid extraction methods. The sample recoveries with the use of solid phase extractions were excellent for most pesticides. Analyte concentration by a factor as great as 1000-fold was achieved readily. The adsorbed pesticides were eluted from the solid …
Chemical Composition Of Particles Of D < 0.20 Mu In The Lower Stratospheric Aerosol, Spring 1993, Joseph D. Scott, David M. Chittenden Ii
Chemical Composition Of Particles Of D < 0.20 Mu In The Lower Stratospheric Aerosol, Spring 1993, Joseph D. Scott, David M. Chittenden Ii
Journal of the Arkansas Academy of Science
The majority of the mass of stratospheric aerosol collected during the spring of 1993 consisted principally of particles of d >0.20 mu containing a mixture of H2SO4 and (NaK)2SO4. However, the composition of the more numerous particles with d< 0.2 mu was very different. X-ray emission spectra (EDS) of individual particles indicated that there were three different chemical populations of small particles. The most numerous population was almost all C with only traces of S and Na. The second population contained metal sulfates and chlorides, possibly accreted to a C-containing matrix. The third population consisted of S- and Cl- containing species and trace amounts of Na and K ions. The number of equivalents of metal ion was much less than that of S and Cl species, indicating that most of the S and Cl was not ionic, but was covalently bonded, perhaps to a C matrix.
Synthesis Of A Ruthenium-Tetra(Tht)Dichloride Compound And The Molecular Structure Of The Partially Oxidized Compound Rucl2(Tht)2.2(Tht-O)1.8, L. A. Thornton, Mark Draganjac, Andres Meza, A. W. Cordes
Synthesis Of A Ruthenium-Tetra(Tht)Dichloride Compound And The Molecular Structure Of The Partially Oxidized Compound Rucl2(Tht)2.2(Tht-O)1.8, L. A. Thornton, Mark Draganjac, Andres Meza, A. W. Cordes
Journal of the Arkansas Academy of Science
No abstract provided.
Non-Commercial Software For The Analysis And Interpretation Of High Resolution Molecular Spectra, A. R. Ford, Scott W. Reeve
Non-Commercial Software For The Analysis And Interpretation Of High Resolution Molecular Spectra, A. R. Ford, Scott W. Reeve
Journal of the Arkansas Academy of Science
No abstract provided.
Synthesis And Characterization Of A Ruthenium-Thioxane Complex, Amanda Wroble, Scotty Sproles, Mark Draganjac, Paul M. Nave
Synthesis And Characterization Of A Ruthenium-Thioxane Complex, Amanda Wroble, Scotty Sproles, Mark Draganjac, Paul M. Nave
Journal of the Arkansas Academy of Science
No abstract provided.
Hammett Correlations Of The Amide Proton Chemical Shift In A Series Of 1-Tosyl-3-(4-Substituted Phenyl)Ureas, Frank L. Setliff, Melody K. Harrison
Hammett Correlations Of The Amide Proton Chemical Shift In A Series Of 1-Tosyl-3-(4-Substituted Phenyl)Ureas, Frank L. Setliff, Melody K. Harrison
Journal of the Arkansas Academy of Science
No abstract provided.
Preparation Of An Electrophilic 3-Methylindole Derivative: Difficulties In Forming A Stable, Suitable Material For The Preparation Of Tryptophan, Jason Boggs, Mariah Mcmasters, Robert W. Curley Jr., Michael J. Panigot
Preparation Of An Electrophilic 3-Methylindole Derivative: Difficulties In Forming A Stable, Suitable Material For The Preparation Of Tryptophan, Jason Boggs, Mariah Mcmasters, Robert W. Curley Jr., Michael J. Panigot
Journal of the Arkansas Academy of Science
In an attempt to prepare stereoselectively beta-deuterated tryptophan, N-protected indole-3-methanol compounds were prepared with model studies being done on undeuterated material. Conversion of these compounds to electrophilic species proved exceptionally difficult and resulted in very low yields or recovered starting material only. A summary of the current results utilizing N-tosyl indole-3-methanol will be presented as well as efforts using N-Boc indole-3-methanol.
Reaction Of Alpine-Borane With Aldehydes: Reactivity Rate Assessment By Observation Of The Disappearance Of The Carbonyl N - Pi* Peak By Uv-Visible Spectroscopy, Layla Bland, Michael J. Panigot
Reaction Of Alpine-Borane With Aldehydes: Reactivity Rate Assessment By Observation Of The Disappearance Of The Carbonyl N - Pi* Peak By Uv-Visible Spectroscopy, Layla Bland, Michael J. Panigot
Journal of the Arkansas Academy of Science
Due to an unexpectedly difficult reduction of indole-3-carbaldehyde and of isobutyraldehyde using the chiral reducing agent Alpine-Borane, the reactivity of several aliphatic, aromatic, and unsaturated aldehydes was investigated. This was done in order to determine whether there was a relationship between aldehyde structure and reduction rate. It was found that aliphatic aldehydes and aromatic aldehydes with no strongly electron-donating groups on the arene ring reduced faster than unsaturated aldehydes.
Hammett Correlations Of The Sulfonamide Proton Chemical Shift In A Series Of N-(Substituted Aryl)-P-Toluenesulfonamides, Frank L. Setliff, Tyson K. Spradlin
Hammett Correlations Of The Sulfonamide Proton Chemical Shift In A Series Of N-(Substituted Aryl)-P-Toluenesulfonamides, Frank L. Setliff, Tyson K. Spradlin
Journal of the Arkansas Academy of Science
No abstract provided.
Preparation Of Methyl 5-Chloro-6-Fluoronicotinate By Fluoride-Chloride Exchange, Frank L. Setliff, Leslie B. Coop
Preparation Of Methyl 5-Chloro-6-Fluoronicotinate By Fluoride-Chloride Exchange, Frank L. Setliff, Leslie B. Coop
Journal of the Arkansas Academy of Science
No abstract provided.
Analysis Of A Mixture Of Several Dihalonicotinic Acids By Gas Chromotography And Gas Chromotography-Mass Spectrometry, Cheryl L. Fossler, Frank L. Setliff, Ali U. Shaikh
Analysis Of A Mixture Of Several Dihalonicotinic Acids By Gas Chromotography And Gas Chromotography-Mass Spectrometry, Cheryl L. Fossler, Frank L. Setliff, Ali U. Shaikh
Journal of the Arkansas Academy of Science
Six 2,5- and 5,6- dihalonicotinic acids in a mixture were converted to their corresponding methyl esters and then analyzed by gas chromatography and gas chromatography-mass spectrometry. Four methods of conversion were compared for their GC sensitivity, efficiency and analysis time. In Method #1, using HC1 and methanol as the reagents, the displacement of the halogens by chlorine (from HC1) at 2- and 6-positions was a common occurrence, rendering the method inefficient. In Method #2 (BF3/methanol), the displacement of halogens by methoxide was evident. Method #3 (dicyclohexylcarbodiimide/methanol) produced a mixture of derivatives with a poor yield. Method #4 (diazomethane) gave a …
Reductive Dechlorinatin Of A 2-Chloronicotinic Acid Under Finkelstein Conditions, Frank L. Setliff, Leslie B. Coop
Reductive Dechlorinatin Of A 2-Chloronicotinic Acid Under Finkelstein Conditions, Frank L. Setliff, Leslie B. Coop
Journal of the Arkansas Academy of Science
No abstract provided.
Electrodeposition Of Copper Indium Sulfide Films From Organic Solutions, Arif Raza, Robert Engelken, Brandon Kemp, Imran Khan, Wasim Aleem, Chris Barber
Electrodeposition Of Copper Indium Sulfide Films From Organic Solutions, Arif Raza, Robert Engelken, Brandon Kemp, Imran Khan, Wasim Aleem, Chris Barber
Journal of the Arkansas Academy of Science
We report on organic solutions ofCuCl 2 ,InClg, and elemental sulfur for electrodepositing CuIn x Sv films. CuInS 2 and CuInSe 2 are promising solar cellmaterials; our work on CuInSg prefaces planned work on plating CuInSe 2 from nonaqueous solvents. Two promising solvent systems are (1) mixed propylcne carbonate and water and (2) mixed ethylene glycol, propionic acid, and water (Engelken et al., 1988). Gray-brown films ofCuInx Sy (nominally GuInS2 ) have been plated from both baths. Major problems include (1) reduction ofCu+2 to Cu and Cu x S by the solvent at high temperatures (T>l()0°C), hence depleting Cu+2,(2) …
Hammett Correlations Of Carbonyl 13c Chemical Shifts In A Series Of N-(4-Substituted Phenyl)-6-Chloro-5-Fluoronicotinamides, Frank L. Setliff, John W. Hawley, Alan D. Toland
Hammett Correlations Of Carbonyl 13c Chemical Shifts In A Series Of N-(4-Substituted Phenyl)-6-Chloro-5-Fluoronicotinamides, Frank L. Setliff, John W. Hawley, Alan D. Toland
Journal of the Arkansas Academy of Science
A series of nine N-(4-substituted phenyl)-6-chloro-5- fluoronicotinamides exhibited excellent correlations of their carbonyl 13C shifts (5CO,ppm as measured in DMSO) with the standard Hammett substituent constants (c?R) of the substituent inthe 4-position. The linear relationship was defined by the equation 8CO ¦ 1.22
Scf-Mo Conformational Analysis Of Polycroconaine, T. E. Ezell, Jerry A. Darsey
Scf-Mo Conformational Analysis Of Polycroconaine, T. E. Ezell, Jerry A. Darsey
Journal of the Arkansas Academy of Science
Abinitio calculations at the STO-3G basis set level using GAUSSIAN 92 were conducted on the monomer unit of polycroconaine, a conducting polymer with conductive properties similar to several metals, in order to determine the most probable conformation of the monomer. We also compared the energy difference between the highest occupied and lowest unoccupied molecular orbitals. Successive calculations were performed at dihedral angle intervals of 30° around the central bond of the monomer. Minimum energy was observed at 0° bond rotation, consistent with a theory that the polymer owes many of its conductive properties to a planar configuration in combination with …
Boron Phosphate And Aluminum Phosphate Aerogels, David A. Lindquist, Steven M. Poindexter, Sterling S. Rooke, D. Ritchie Stockdale, Kirk B. Babb, Alison L. Smoot, William E. Young
Boron Phosphate And Aluminum Phosphate Aerogels, David A. Lindquist, Steven M. Poindexter, Sterling S. Rooke, D. Ritchie Stockdale, Kirk B. Babb, Alison L. Smoot, William E. Young
Journal of the Arkansas Academy of Science
Anhydrous sol-gel condensation of triethyl phosphate [(CH3CH2O)3PO] with boron trichloride (BCL3 ) or triethyl aluminum [(CH3CH2 ) 3A1] in organic solvents, led to formation of metallophosphate gels. The pore fluid of the gels was removed under supercritical conditions in a pressurized vessel to form aerogels. The aerogels were then calcined at progressively higher temperatures to produce high surface area phosphates. Since the initial gel reagent mixtures contained several NMR active nuclei, the condensation chemistry prior to the gel point was monitored by solution nB NMR. The surface areas, distribution of pore sizes, and total pore volumes of the aerogel products …
Reaction Of Titanocene Dichloride With Acetylenedicarboxylate, Tanya L. Hagler, Mark Draganjac, Paul M. Nave, J. Ed Bennett, Farooq Kahn, Robert Engelken, Gerard Williams, Chris Poole, Kwok Fai Yu
Reaction Of Titanocene Dichloride With Acetylenedicarboxylate, Tanya L. Hagler, Mark Draganjac, Paul M. Nave, J. Ed Bennett, Farooq Kahn, Robert Engelken, Gerard Williams, Chris Poole, Kwok Fai Yu
Journal of the Arkansas Academy of Science
The reaction of Cp2TiCl2 with either the mono- or dipotassium salt of acetylenedicarboxylic acid (ADC) gives high yields of an insoluble orange product. The insoluble compound shows potential semiconductor behavior, as evidenced by an apparent bandgap in the orange region of the visible spectrum. Under N2 ,the compound decomposes at 238° C, eventually losing approximately 46% total mass up to 1350° C. The exothermic decomposition in air, beginning at 235° C, results in the formation of titanium oxides.
Analysis Of Ammunition By X-Ray Fluorescence, Michael W. Rapp, Teddy L. Townsend
Analysis Of Ammunition By X-Ray Fluorescence, Michael W. Rapp, Teddy L. Townsend
Journal of the Arkansas Academy of Science
Nondestructive analysis of lead shotgun pellets by X-ray fluorescence (XRF) shows considerable promise in assignment of the identity of the ammunition source. X-ray fluorescence spectra of various shotgun pellets and of standard alloys were obtained using an energy-dispersive instrument and an Am-241 source. The correlation obtained between the precent antimony in the standard alloys and the intensity of the Ka fluorescence peak from antimony was excellent. Peak areas from antimony in shotgun pellets were measured and compared to calibration plots from the standard alloys. The method was capable of distinguishing among lead-based alloys, such as ammunition, with antimony content as …