bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinetics and Mechanism of Oxidation of Dimethyl Sulfoxide by Peroxomonosulfate
Authors: Pandurengan Thanthoni , Maruthamuthu Pichai 
Published: July 2006

Abstract
The kinetics of oxidation of dimethyl sulfoxide (DMSO) by peroxomonosulfate (PMS) was carried out in aqueous H2SO4 medium (0.1–0.5 M H+) and in buffered media, pH=4.6 and 7.0, at temperatures, 10 and 20 °C. The reaction obeys a total second order kinetics, first order each with respect to [PMS] and [DMSO]. The rate was found to be immeasurably fast at pH≥9 and T&gt;20 °C. In strong acid medium, [H2SO4]=0.1–0.5 M, the reaction was found to follow an inverse first order dependence on [H+]. The rate law for the disappearance of PMS is found to be
Rate={ka+kb[H+]−1}[PMS][DMSO]
indicating both the acid-independent and inverse acid-dependent reactions occurring concurrently. Dimethyl sulfone was identified as the oxidation product and the reaction stoichiometry, [DMSO]:[PMS] was found to be 1:1. The kinetic and thermodynamic parameters evaluated strongly suggest the nucleophilic substitution mechanism characteristic of peroxides. A comparison is also made with the corresponding reactions of the similar peroxides, H2O2, S2O82−, P2O84−, and H2PO5−.
Partial Hydrogenation of Acetylenes on Modified Nickel Boride Catalysts
Authors: Nitta Yuriko , Imanaka Toshinobu , Teranishi Shiichiro 
Published: July 2006

Abstract
Ni–B catalysts modified with a small amount of copper(II) salt have a higher selectivity than palladium and modified Raney nickel catalysts for partial hydrogenation of phenylacetylene, 1-heptyne, 1-ethynylcyclohexene, and propargyl alcohol.
The Molecular Conformation of 6,14-Di-O-acetyl-3-O-(2-chlorobenzoyl)-grayanotoxin II as Revealed by X-Ray Methods
Authors: Furusaki Akio , Hamanaka Nobuyuki , Matsumoto Takeshi 
Published: July 2006

Abstract
An X-ray crystal analysis has revealed that the six-membered C-ring in the title compound takes a boat conformation, in contrast with that in grayanotoxin II itself.
Equilibrium Dissociation Pressure of Hydrogen in Molten LiCl–LiH Mixtures
Authors: Ichikawa Kazuhiko , Kawamura Kazutaka 
Published: July 2006

Abstract
Pressure-composition-temperature data were collected for the LiCl-LiH system in the respective ranges 0.1–10 mmHg, 4.5–22.3 mol% LiH, and 550–700 °C by measuring equilibrium hydrogen pressure in a Sieverts’ apparatus. The square root of hydrogen pressure vs. composition isotherm follows Sieverts’ relation for compositions below 10 mol% LiH.
Preparation and Circular Dichroism Spectrum of a (Triazacyclononane)(tribenzo[b,f,j] [1,5,9]triazacyclododecene)cobalt(III) Complex
Authors: Fujinami Shuhei , Hosokawa Takao , Shibata Muraji 
Published: July 2006

Abstract
A new [Co(tacn)(tri)]3+ complex has been prepared and optically resolved (TACN represents 1,4,7-triazacyclononane, and TRI, tribenzo[b,f,j][1,5,9]triazacyclo dodecene). From the CD spectral similarity of (+)500CD-[Co(tacn)(tri)]3+ with (+)546[Co(tri)2]3+, it has been concluded that the metal-centered optical activity of the two tri complexes is derived from a chiral arrangement of (benzene ring)–C=N– moieties.
MINDO/3 Calculations of Kinetic Isotope Effects in Heterolysis of Neopentyl Alcohol
Authors: Ando Takashi , Yamataka Hiroshi , Yabushita Satoshi , Yamaguchi Kizashi , Fueno Takayuki 
Published: July 2006

Abstract
Geometrical optimization of the protonated neopentyl alcohol and the transition state of its heterolysis was carried out using the MINDO/3 SCF-MO method. A cyclic structure was predicted for the transition state. Agreement between the calculated and experimental values for the carbon-14 kinetic isotope effects was excellent.
Preparation of (R)-N,N-Dimethyl-1-[2-(diphenylphosphino)ferrocenyl]-2-propanamines and Asymmetric Grignard Cross-coupling Catalyzed by Nickel Complexes with the Phosphine Ligands
Authors: Hayashi Tamio , Konishi Mitsuo , Hioki Takeshi , Kumada Makoto , Ratajczak Aleksander , Niedbala Halina 
Published: July 2006

Abstract
A pair of diastereoisomeric phosphines, (R)-N,N-dimethyl-1-[2-(diphenylphosphino) ferrocenyl]-2-propanamines, have been prepared and used as ligands for nickel-catalyzed asymmetric cross-coupling of 1-phenylethylmagnesium chloride with vinyl bromide to give 3-phenyl-1-butene of 14–15% enantiomeric excess.
An NMR Study on the Association Stabilities of Thiaheterohelicenes against 7,7,8,8-Tetracyanoquinodimethan. Effect of the Staggered Configuration of Helicene
Authors: Tanaka Hisao , Nakagawa Hiroko , Yamada Koh-ichi , Kawazura Hiroshi 
Published: July 2006

Abstract
In order to evaluate the influence of the staggered configuration of helicene on complex formation, a 1H NMR technique was applied to the complexing equilibria of thiaheterohelicene homologs with 7,7,8,8-tetracyanoquinodimethan (TCNQ). Formation constants of the complexes showed irregular changes in the case of [5] and [7]thiaheterohelicenes in which the staggerings occur. This irregularity could be interpreted on the basis of the observed abnormal decrease of the bonding entropy. The reduced bonding entropy was understood in terms of the incomplete quenching of internal freedom, which was expected from the peculiar orientation of the staggered thiaheterohelicene towards planar TCNQ, in the charge-transfer complex.
A Study of the Electronic States of Iridium(III) Complexes Containing 1,10-Phenanthroline Ligands. The Contribution of a dd Excited State to the Lowest Triplet State
Authors: Ohashi Yukako 
Published: July 2006

Abstract
To investigate the solvent dependence of the dd contribution to the lowest excited state of cis-[IrCl2L2]Cl (L=1,10-phenanthroline (phen) and 5,6-dimethyl-1,10-phenanthroline (5,6-Mephen)), the triplet-triplet absorption spectra (15000–25000 cm−1) were measured in N,N-dimethylformamide (DMF)–water mixed solvents. From a smaller solvent-dependence of the absorption intensity for [IrCl2(5,6-Mephen)2]Cl than for [IrCl2(phen)2]Cl, the lowest triplet state of the former is considered to have a ππ* character in 95% v/v DMF–water and 45% v/v DMF–water. However, in pure water a considerable decrease in the triplet-triplet absorbance was observed. Because the molar extinction coefficient of the triplet-triplet absorption of the dd-dd type is 10−2 times smaller than that of the ππ*-ππ* type, the observed decrease in the absorbance is elucidated by the increase in the contribution of the dd state to the lowest triplet state. Using ethanol–methanol (4 : 1, v/v) as a solvent, it was confirmed that the triplet-triplet absorption spectrum shows no change when the solutions are degassed and the temperature is lowered (77 K).
The Cadmium-photosensitized Reaction of Saturated Tertiary Amines
Authors: Yamamoto Shunzo , Yasunobu Masae , Nishimura Norio 
Published: July 2006

Abstract
Rate constants for the quenching of the cadmium resonance line at 326.1 nm by triethylamine (TEA), N-ethylpiperidine (NEP), and 1-azabicyclo[2.2.2]octane (ABCO) were obtained. Relative rate constants for the formation of an exciplex between an excited cadmium atom and these amines and quantum yields for the emission from the exciplex were also obtained. Contrary to the case of primary amines, in which the electron-donating ability of the nitrogen atom is operative, the exciplex formation in the present case is mainly governed by the magnitude of the steric effect of ethyl groups on the interaction between the nitrogen atom and an excited cadmium atom. Gaseous products were hydrogen, methane, ethane (and/or ethylene), and butane. The quantum yields of these products indicate that the primary photochemical products are methyl and ethyl radicals for TEA and NEP. The amount of products for ABCO was considerably smaller than those for other amines.
Reactions of Aromatic Radical Anions with Benzhydryl Chloride Studied by Pulse Radiolysis
Authors: Takamuku Setsuo , Kigawa Hitoshi , Toki Susumu , Tsumori Kunihiko , Sakurai Hiroshi 
Published: July 2006

Abstract
Reactions of the aromatic radical anions with benzhydryl chloride have been investigated by pulse radiolysis. The second-order rate constants were determined for the reactions of benzhydryl chloride with various aromatic radical anions. On the basis of the linear relationship between the free energy and the activation energy, an irreversible electron transfer with an early transition state was elucidated.
Partition of Carboxylic Acids between Benzene and Aqueous Solution as Considered from the Regular Solution Theory
Authors: Fujii Yukio , Tanaka Motoharu 
Published: July 2006

Abstract
The partition of carboxylic acids between benzene and 0.1 mol dm−3(H,Na)ClO4 aqueous solution has been studied at 25 °C. Carboxylic acids used include acetic, propanoic, butanoic, pentanoic, hexanoic, and decanoic acids. The hydration of monomeric acids in benzene being taken into account, the hydration-corrected partition constant has been calculated. The effect of the chain length on the partition is accounted for with the aid of the newly estimated solubility parameters and empirical binary coefficients. Applicability of the empirical solubility parameter of water (35.89 J1⁄2 cm−3⁄2) has also been discussed.
Spectrophotometric Determination of Formation Constants and Estimation of Molar Absorption Spectra of Individual Components in Chemical Equilibria. Infrared Study of Intermolecular Hydrogen Bonding of 2-Aminopyridine
Authors: Sugeta Hiromu 
Published: July 2006

Abstract
A general method is developed for evaluating formation constants and molar absorption coefficients of constituent species from spectrophotometric data for a multicomponent equilibrium system. The method is applied to analyzing infrared spectra for the intermolecular hydrogen bond system of 2-aminopyridine in carbon tetrachloride solution. 2-Aminopyridine assumes a cyclic dimer structure by dint of an intermolecular hydrogen bonding and the formation constant for the dimerization is 1.4±0.1 mol−1 dm3 at 30 °C.
Electrochemical Properties of Ferrocenophanes. I. Voltammetric Studies on the Oxidation of Mono-, Di-, and Tri-bridged Ferrocenophanes in Acetonitrile
Authors: Ogata Tateaki , Oikawa Kazuo , Fujisawa Tadashi , Motoyama Shunsuke , Izumi Taeko , Kasahara Akira , Tanaka Nobuyuki 
Published: July 2006

Abstract
Electrode reactions of mono-, di- and tri-bridged ferrocenophanes ([3]Fcp, [4]Fcp, [3][3]Fcp, [4][3]Fcp, [4][4]Fcp, [3][3][3]Fcp, [4][4][3]Fcp and [4][4][4]Fcp) in acetonitrile were investigated by direct current polarography, pulse polarography, and cyclic voltammetry. The oxidation of these compounds proceeds reversibly as a one-electron process. The linear relationship between the half-wave potential and the number of methylene groups was obtained for ferrocene and ferrocenophanes other than [3][3]Fcp and [3][3][3]Fcp. The Taft substituent constants of trimethylene and tetramethylene groups were estimated.
Reactions of Manganese(III) Schiff Base Complexes with Superoxide Ion in Dimethyl Sulfoxide
Authors: Matsushita Takayuki , Shono Toshiyuki 
Published: July 2006

Abstract
The reactions of the chloromanganese(III) complexes of the Schiff bases derived from salicylaldehydes or β-diketones and diamines or monoamines with superoxide ion, O2−, in dimethyl sulfoxide were investigated. The complexes were found to react to give either the oxygenated Mn Schiff base complexes or the reduced Mn(II) Schiff base complexes. The difference in the reactivity toward O2− was correlated to the polarographic half-wave potentials corresponding to the reduction of Mn(III) to Mn(II) of the complexes. Some oxygenated complexes were isolated and characterized.
Binding of Sodium Decyl Sulfate to a Cationic Polymer
Authors: Shirahama Keishiro , Yuasa Hidefumi , Sugimoto Shinji 
Published: July 2006

Abstract
Interaction between sodium decyl sulfate and a cationic copolymer of dimethyldiallylammoniurn chloride and sulfur dioxide was studied by a potentiometric method utilizing a surfactant-selective electrode. Binding occurs suddenly and is completed in a very narrow range of equilibrium concentration, indicating the strongly cooperative nature of the binding process. The characteristic concentration at which binding starts is about two orders of magnitude smaller than the critical micelle concentration. The cooperativeness parameters as estimated by a nearest neighbor interaction model remains almost constant on increasing sodium chloride concentration, affinity for an isolated binding site decreasing.
The Formation of Molybdenum Disulfide by the Reaction between Molybdenum Trioxde and Sulfur Dioxide in the Presence of Carbon
Authors: Yajima Akimasa , Matsuzaki Ryoko , Eguchi Motonori , Saeki Yuzo 
Published: July 2006

Abstract
The reaction products obtained by heating a mixture of MoO3 and carbon in a SO2 stream at various temperatures were examined. The possible reactions during the above process were also studied. Further, thermodynamical consideration was made of the formation of MoS2. When a mixture of MoO3 and carbon was heated in a SO2 stream, MoO2 was formed above 400 °C. At 500–550 °C, the formation of a small amount of Mo4O11was also observed. Above 700 °C, the formation of MoS2 in addition to MoO2 was observed, and MoS2 alone was obtained at 1000 °C. Sulfur was obtained outside the heating zone throughout the temperature range in this experiment. The process of the formation of MoS2 by the reaction between MoO3 and SO2 in the presence of carbon can be represented as follows: The reaction between carbon and SO2 occurs at first to form sulfur. Above ca. 400 °C, the reductions of MoO3 with carbon and with sulfur occur to form MoO2. Above ca. 700 °C, MoS2 is formed by the reaction between MoO2 and sulfur, which are formed by the above reactions.
Selective Extraction Spectrophotometric Determination of Iron by Utilizing the Peculiar Absorption of Iron(II)–2-(2-Thiazolylazo)-5-dimethylaminophenol Complex
Authors: Ueda Kazumasa , Kiyota Yasushi , Yamamoto Yoshikazu 
Published: July 2006

Abstract
Thiazolylazo compounds react with iron(II) to form brownish complexes, which show a characteristic absorption in near-infrared region. These compounds possess the hydroxyl group in the o-position next to the azo group. Among them, iron(II)-2-(2-thiazolylazo)-5-dimethylaminophenol complex has the absorption maximum at 760 nm in chloroform; the optimum pH for iron extraction lies between 8.2–10.0. Beer’s law holds up to 2.0 μg cm−3 of iron and the molar absorption coefficient is 2.70×104 dm3 mol−1 cm1. The composition and the extraction constant of the complex are estimated to be Fe: TAM=1 : 2 and logKex=−4.20±0.04, respectively. Since the present method utilizes the specific absorption of the iron(II)-TAM complex, the presence of many ions is tolerable, especially of 3d type metals. The method was applied to the determination of traces of iron dissolved in river and sea waters with satisfactory results.
Electronic Structures and Spectra of the Enol Form of Some β-Diketones
Authors: Morita Hiroshi , Nakanishi Hiroshi 
Published: July 2006

Abstract
Near and vacuum UV absorption spectra have been measured with benzoylacetone (BA), dibenzoylmethane (DBM), and 3-phenyl-2,4-pentanedione (PPD) in heptane, in acetonitrile, and in ethanol at room temperature. Theoretical analysis of the spectra with the aid of the composite molecule method clearly shows that the π-electron interaction between the enol ring and the benzene ring is rather strong in BA and DBM, but is weak in PPD. The charge-transfer (CT) bands from the benzene ring to the enol ring are observed at 44000 cm−1 in BA, at 40000 and 44000 cm−1 in DBM, and at 41500 and 43800 cm−1 in PPD. The electronic structure of the enol form of malonaldehyde has been elucidated by a modified CNDO-CI method; the result indicates the first and second σ-σ* excited states predicted at 8.76 and 9.35 eV being the CT band pertinent to the intramolecular hydrogen-bonding.
Bovine Serum Albumin Coordinated Iron-Sulfur Cluster as a Hydrogenase Model
Authors: Okura Ichiro , Nakamura Satoshi , Kobayashi Masatoshi 
Published: July 2006

Abstract
The bovine serum albumin coordinated Fe4S4-cluster, which had hydrogenase activity, was synthesized. Its physical and chemical characteristics were then compared with those of natural hydrogenase. Though the affinities of hydrogenase and the albumin-coordinated Fe4S4-cluster for the substrate, methyl viologen, were similar, the hydrogenase activity for hydrogen evolution was 105 times greater than the cluster. Two types of Fe4S4-clusters, coordinated by the fragments of the cleaved albumin obtained by treatment with cyanogen bromide, were synthesized, and their hydrogenase activities were compared. The activity with the iron-sulfur cluster incorporated in the fragment with MW 40000 was much higher than that of the one incorporated in the fragment with MW 20000. The amino acid arrangement to form the active site was discussed on the analogy of the other iron-sulfur proteins.
Cyclic Voltammetry of Aromatic Amine N-Oxides in Nonaqueous Solvents and the Stability of the Free Radicals Produced
Authors: Miyazaki Hiroshi , Matsuhisa Yoshio , Kubota Tanekazu 
Published: July 2006

Abstract
Cyclic voltammograms of aromatic amine N-oxides were recorded in nonaqueous solvents at various sweep rates less than 10 V/s. The measurement was carried out for both cathodic and anodic sweeps, and the sweep rate for obtaining a good cyclic voltammogram was correlated with the wave height of the a.c. polarogram in the reduction and oxidation processes, respectively. A good correlation was found between the sweep rate and the wave height in both the reduction and oxidation processes. This confirmed that the two values serve as good measures of the stability of the anion or cation free radical produced by the electrode reaction of the aromatic amine N-oxides. The data were also examined by comparison with results from an electron spin resonance study. Finally, the temperature effect on the cyclic voltammogram of pyridine N-oxide was investigated in detail.
The Action of Boron Trifiuoride on Aromatic Nitrile Oxides
Authors: Shiraishi Shinsaku , Shigemoto Tadashi , Miyahara Masatoshi , Ogawa Shojiro 
Published: July 2006

Abstract
The action of boron trifluoride etherate on stable aromatic nitrile oxides effected the isomerization of nitrile oxides into isocyanates competitively with their dimerization to 1,4,2,5-dioxadiazines and/or (1,2,4-oxadiazol-4-io)oxytrifluoroborates. Quenching the reaction with methanol at an earlier stage of the reaction gave methyl benzohydroximate. The reacion was interpreted in terms of the initial coordination of BF3 with the nitrile-oxide-oxygen atom.
Solid Phase Synthesis of Crystalline Protected Penta-l-tryptophan Methyl Esters
Authors: Ueki Masaaki , Ikeda Shigeru , Handa Takashi 
Published: July 2006

Abstract
Solid phase syntheses of protected tryptophan homo-oligomers were accomplished by utilizing dimethylphosphinothioyl(Mpt) group as an Nα-amino protecting group which was removed by treatment with triphenylphosphine dihydrochloride. By measurements of the ultraviolet and fluorescence spectra it was ascertained that no modification on the tryptophan indole ring had occurred during these syntheses.
The Photoelectrochemical Reaction of the Chlorophyll-Irisquinone Electrode
Authors: Takahashi Fujio , Seki Katsura , Kaneko Ryohei , Sato Kenji , Kusumoto Yasushi 
Published: July 2006

Abstract
The role of irisquinone (IQ) in the chlorophyll-IQ electrode was studied by measuring the photoresponse under illumination and the photocurrent at the controlled potential. It was concluded that the hydrophobic property of IQ was necessary for the photoresponse to occur at the chlorophyll electrode, and that the photoexcited chlorophyll was likely to eject electrons to a counter electrode via an outer circuit and to pull electrons from the reduced IQ, which had been produced by the oxidation of a reducing compound in the electrolyte on the chlorophyll-IQ electrode.
Stereochemical Behavior of 1-Methoxycyclopropyl Radical in Hunsdiecker Reaction
Authors: Ando Teiichi , Ishihara Takashi , Yamashita Akira , Matsumoto Masahiro 
Published: July 2006

Abstract
The Hunsdiecker reaction of Ag (E)- and (Z)-2,2-dichloro-1-methoxy-3-methylcyclopropanecarboxylates with bromine in CCl4 at 0 and 77 °C occurs with substantial inversion of configuration, suggesting that the 1-methoxycyclopropyl radical is configurationally less stable than the 1-fluorocyclopropyl or the 1-methoxyvinyl radical.
Electron Spin Resonance Study on the Difference of Structure in Diastereomeric Nitroxyl Radicals
Authors: Kotake Yashige , Kuwata Keiji 
Published: July 2006

Abstract
Electron spin resonance spectra of nitroxyl radicals bearing two asymmetric carbons were observed. The radicals were produced by the abstraction of a hydrogen atom from ethers and amines by photoexcited benzophenone, followed by spin trapping with phenyl-N-t-butylnitrone. The spectra showed the presence of two radical species assignable to diastereomers in most cases. The presence of isomers was seen more clearly in ESR spectra of radicals produced from ethers than those from amines. The origin of the different ESR parameters of the isomer was discussed in detail and it was concluded that the functional group on β-carbon acts as a group of proximity to nitroxyl function. The difference of the electronegativity of the atom in each functional group causes the difference of the extent of the separation of isomers. The effects of proximity groups on observed ESR parameters are concluded to be the same as the solvent effect.
Redox Reaction of the Central Metal Ions Coordinated to Tetra(p-sulfophenyl)porphine(TPPS). I. Photoreduction of Co(III)TPPS by Methanol and 2-Propanol
Authors: Hatano Keiichiro , Usui Kiyoko , Ishida Yoshitaka 
Published: July 2006

Abstract
Trivalent cobalt ion coordinated to 5,10,15,20-tetra(p-sulfophenyl)porphine (TPPS) in deaerated solution was reduced to the divalent ion on illumination of light with simultaneous oxidation of alcohols. The resulting divalent ion in the porphyrin was reoxidized by admission of dioxygen or air into the solution. It was found that the metalloporphyrin played a photocatalytic role in the autoxidation of alcohols. The kinetic study on the photoreduction revealed that the reduction rate of Co(III) followed the pseudo-first-order rate expression at 20 °C and pH 6.5 to 11.5 in the presence of excess methanol or 2-propanol. The observed rate constants were dependent on [alcohol] and/or pH. Possible mechanism for the photoreduction of Co(III)TPPS in the aqueous solution was discussed in terms of preequilibrium reactions of the axial ligation of substrates to the metalloporphyrin.
New Application of Crown Ether. V. The Effect of Crown Ethers on the Acid–Base Interaction between 2,4,4′,6-Tetranitrodiphenylamine and Primary Amines in Benzene
Authors: Wada Fumio , Wada Yoshiko , Kikukawa Kiyoshi , Matsuda Tsutomu 
Published: July 2006

Abstract
The effect of crown ethers on the acid-base interaction of 2,4,4′,6-tetranitrodiphenylamine (HA, λmax 380 nm, pKa=8.88 in water) with primary amines (RNH2) in benzene was investigated spectrophotometrically. Crown ethers assisted strongly the formation of association complexes, R\overset+NH3·crown ether·A−, which existed as a single chemical species (λmax 478 nm) assignable to “crown ether-separated ion pair.” The effect of the steric factors of various primary amines on the equilibrium to form the association complex was discussed on the basis of the equilibrium constants and thermodynamic parameters of the systems involving 18-crown-6 and benzo-18-crown-6.