bluuebunny/crossref_metadata_2025 huggingface dataset:
The Preparation of Poly(dihydroxyphenylene) through the Electro-Oxidative Polymerization of Hydroquinone
Authors: Yamamoto Kimihisa , Asada Toshio , Nishide Hiroyuki , Tsuchida Eishun
Published: July 2006

Hydroquinone is electro-oxidatively polymerized to poly(dihydroxyphenylene) on the Pt electrode, whose structure was confirmed by spectroscopic measurements. The polymerization proceeds via an oxidative and cationic mechanism. The poly(dihydroxyphenylene) thus formed is a Nernstian-type electro-active polymer (E°=0.7 V vs. Ag/AgCl in an acidic medium) and shows a redox reaction through two-electron transfer, accompanied by proton dissociation on the Pt electrode.
Activated Nitriles in Heterocyclic Synthesis. Novel Synthesis of 5-Imino-5H-[1]benzopyrano[3,4-c]pyridine-4(3H)-thiones and Their Oxo Analogues
Authors: Elgemeie Galal E H , Elghandour Ahmed H H
Published: July 2006

Various benzopyrano[3,4-c]pyridine-4(3H)-thione derivatives and their oxo analogues were prepared by condensation of cyanothioacetamide or cyanoacetamide and salicylaldehyde with ketones or activated nitriles in the presence of ammonium acetate.
The Determination of Film Resistance by Means of the Frequency at the Maximum Phase Angle and the Estimation of the Degradation of the Coating Film
Authors: Sekine Isao , Sakaguchi Kazuhiko , Yuasa Makoto
Published: July 2006

The determination of film resistance (Rf) was investigated by means of the frequency at the maximum phase angle (fθmax), as obtained from electrochemical impedance measurements. fθmax was linearly correlated with Rf. The degradation of the coating film was obviously and rapidly evaluated from fθmax by comparison with Rf.
Synthesis of Phenethylamines by Hydrogenation of β-Nitrostyrenes
Authors: Kohno Masahiko , Sasao Shigehiro , Murahashi Shun-Ichi
Published: July 2006

Catalytic hydrogenation of β-nitrostyrenes over palladium on charcoal in EtOH–HCl at low temperature gave the corresponding phenethylamines, which are precursors of 1,2,3,4-tetrahydroisoquinolines, in high yield.
Catalytic Epoxidation of Cyclooctene with Oxygen Using Electrochemically Reduced Metalloporphyrins
Authors: Ojima Fumihiro , Kobayashi Nagao , Osa Tetsuo
Published: July 2006

Epoxidation of cyclooctene with molecular oxygen was achieved using electrochemically reduced metalloporphyrins in N,N-dimethylformamide (DMF) containing acetic anhydride as an electrophile. Turnover numbers 5–7 based on moles of cyclooctene oxide produced per moles of porphyrin were obtained by the use of [5,10,15,20-tetrakis(pentafluorophenyl)porphinato]iron(III) chloride and [5,10,15,20-tetra(l-naphthyl)porphinato]manganese(III)chloride. The effects of central metals and substituents on phenyl groups of matalloporphyrins were also investigated. Rate constants (k) were estimated by way of digital simulation of cyclic voltammograms based on a simple ECE reaction mechanism. The reaction mechanism in the presence of cobalt(II) complexes seemed to be somewhat different from that in the presence of iron(III) or manganese(III) complexes.
A Novel Asymmetric Synthesis of Chiral Cyclopentanoid Building Blocks by the Use of Chiral Lithium Amide
Authors: Asami Masatoshi
Published: July 2006

Enantioselective deprotonation of meso-epoxides, derived from 3-cyclopenten-1-ol, was examined using chiral lithium amide. Chiral cis-4-t-butyldimethylsiloxy-2-cyclopenten-1-ol, cis-4-tetrahydropyranyloxy-2-cyclopenten-1-ol, and their trans-isomers, which are useful chiral building blocks for the synthesis of cyclopentanoid natural compounds, were obtained with high enantiomeric excesses (72–90% ee). Both (R)- and (S)-4-hydroxy-2-cyclopenten-1-one were derived from (1S,4R)-4-t-butyldimethylsiloxy-2-cyclopenten-1-ol stereospecifically.
The Thermal and Photochemical Behavior of the Cyclomers Derived from 1,1′-(1,3-Propanediyl)bis(pyridinyl) Diradicals
Authors: Muramatsu Takashi , Ikegami Yusaku , Hanaya Kaoru , Onodera Shinji
Published: July 2006

Reduction of 1,1′-(1,3-propanediyl)bis(pyridinium) dibromide (5a) with sodium amalgam afforded the meso- and dl-cyclomers formed by intramolecular cyclization of the diradical (2a). The meso-cyclomer (6a) was thermally converted into the dl-cyclomer (7a), while retroversion of 7a into 6a was achieved photochemically. Reduction of the 4,4′-dimethyl (5b) and 4,4′-di-t-butyl (5c) derivatives of 5a similarly afforded the corresponding meso-(6b and 6c) and dl-(7b and 7c) cyclomers, which can be interconverted to each other. Using NMR spectroscopy to follow the reaction the energies for thermal conversion of meso- to dl- cyclomers were found to be 58.6, 74.5, and 84.5 kJ mol−1 for 6a, 6b, and 6c, respectively. Photodissociation of the cyclomers at −196 °C gave the diradicals (2a–2c), which showed characteristic triplet ESR spectra. The ESR spectra for both 2a and 2b indicated that there were two conformations, each with different zero-field splitting parameters, in 2-methyltetrahydrofuran glass. In contrast, the ESR spectrum of 2c indicated that it has only one conformation. The 4,4′-bis(methoxycarbonyl) derivative (2d) of 2a also forms cyclomers which, upon photolysis, regenerate the diradical. It was concluded that 1,1′-(1,3-propanediyl)bis(pyridinyl) diradicals are substantially in thermal equilibrium with the cyclomers.
Heavy-Atom Effect on Decay Dynamics of Triplet-State Ion Pairs. Chloranil–Naphthalene (1:2) Termolecular Systems
Authors: Kobashi Harumichi , Suto Hiroshi , Shizuka Haruo
Published: July 2006

Decay kinetics of triplet-state ion pairs (3IPs) have been studied for the termolecular systems consisting of the chloranil anion radical (CA\ewdot) with the dimer cation radical of naphthalene (Np\underset.+) or its monohalogenated derivatives (NpX2\underset.+) in 1,2-dichloroethane by means of laser photolysis. Marked heavy-atom (HA) effect was found on back electron transfer (back ET) but not on ionic dissociation (ID). A small effect of 1- or 2-brominated compound on 3IP lifetimes was observed. Both back ET and ID processes of 3(CA\ewdot, Np2\underset.+) were found to be almost temperature-independent. Electron-transfer (ET) quenching of 3CA leading to produce the (1:1) 3IP was also independent on the HA substitution. For these kinetic studies, a conventional decay analysis was examined.
Kinetic Solvent Effects on K+/K(Hg)Electrodes in Some Dipolar Aprotic Solvent Systems by Cyclic Voltammetry
Authors: Bhattacharya Swapan K , Kundu Kiron K
Published: July 2006

The rate constants (skR) of K++e (Hg)\ightleftharpoonsK(Hg) in the dipolar aprotic solvents like propylene carbonate (PC), N, N-dimethylformamide (DMF), acetonitrile (AN), and their several binary mixtures have been determined at 25 °C on a hanging mercury drop electrode (HMDE) by cyclic voltammetric measurements. The observed nature of the cyclic voltammograms indicates that the reaction is quasi-reversible in the range of the sweep rates 1.0–0.01 V s−1. An insight to the composition profiles of the free energies of activation (ΔG≠) relative to that in the chosen reference solvent (r) in the respective solvent (s) systems: −δΔG≠(=RTln skR⁄rkR) reveals that not only the solvation of K+ but also that the transition state (TS) are responsible in dictating the rate constants. Also the solvation of TS is being guided by the dispersion interactions as well as the availability of the fraction of the free surfaces (1–θs) for varying adsorption of the solvent molecules on the electrodes, all relative to that of the respective reference solvents.
The Temperature Dependence of the Quenching Rate of the 307.6 nm Zinc Resonance Radiation by Methane and Cyclopropane
Authors: Yamamoto Shunzo
Published: July 2006

The quenching rate constants of Zn(3PJ) by methane and cyclopropane at various temperatures were determined on the basis of the Stern-Volmer plots. The activation energy for the quenching by methane was similar to that by cyclopropane. The frequency factor for the quenching-rate constant by cyclopropane was very large.
Acetylation of 2-C-Benzyl-l-lyxo-3-hexulosono-1,4-lactone
Authors: Kinoshita Takamasa , Yoshida Noritaka , Miwa Toshio
Published: July 2006

Acetylation of 2-C-benzyl-l-ascorbic acid afforded an unexpected enone, 2,6-di-O-acetyl-2-C-benzyl-5-deoxy-d-glycero-hex-4-en-3-ulosono-1,4-lactone (3) of the open form, along with 2,3,5-tri-O-acetyl-2-C-benzyl-l-lyxo-3-hexulosono-1,4-lactone (4) of the closed form.
Synthesis of Some Anhydro Derivatives of Dl-1-C-Hydroxymethyl-1,2,3,4,5,6-cyclohexanehexol
Authors: Ogawa Seiichiro , Urakawa Masaaki , Tonegawa Takeshi
Published: July 2006

Three stereoisomers of Dl-1-C-(hydroxymethyl) conduritol epoxides have been synthesized in order to investigate their inhibitory activity against certain glycosyl hydrolases.
The Epoxidation of C5–C10 Alkenes With Hydrogen Peroxide Catalysed by Mo Compounds in Two-phase Solvents
Authors: Kamiyama Tsutomu , Inoue Masami , Kashiwagi Hiroshi , Enomoto Saburo
Published: July 2006

The epoxidation of terminal alkenes such as 1-heptene, 1-octene, 1-decene, styrene (1), α-methylstyrene, and allyl chloride, and inner alkenes such as α-pinene, cyclopentene, cyclohexene (2) and cyclooctene was carried out with aqueous 60% hydrogen peroxide in the presence of molybdenum blue (Mob)-bis(tributyltin) oxide (3) using a two-phase solvent of chloroform-water at 25 °C. All these olefins gave epoxides in 98 to 48% yields. In the cases of 1 and 2, the addition of ammonia greatly increased the yields of epoxides; the yield reached 78% and 83%, respectively, after 7 h. Various kinds of amines and organotin compounds were examined as co-catalysts and their effects were discussed.
Fractal Pattern Formation of Metal-Containing Polymeric Thin Films Prepared by Plasma Reaction
Authors: Gong Jianping , Kagami Yoshiharu , Yamada Katsuyuki , Osada Yoshihito
Published: July 2006

Three kinds of metal-containing polymeric thin films were obtained from copper acetylacetonate (CuAA), titanium tetraisopropoxide (TiTP) and tetramethyltin (TMT) by plasma polymerization. The vaporized metal-organic compounds underwent chemical rearrangement under the action of energetic plasma to give higher ordered thin films consisting of metal and organic polymer layers. Transmission electron microscopy (TEM) photographs of the films consisting of alternative metal and organic regions showed fractal pattern. The fractal dimensions were calculated as 1.87 for CuAA, 1.94 for TiTP and 1.92 for TMT films, respectively. Formation process of fractal pattern was discussed in terms of chemical structure of starting compounds and plasma conditions.
Synthesis and Some Reactions of 2-(2-Aminoanilino)cyclohepta[b]pyrroles: Leading to 5H-Cyclohepta[1′,2′: 4,5]pyrrolo[2,3-b][1,5]benzodiazepine, a Novel 20π Antiaromatic System, and Cydohepta[1′,2′: 4,5] pyrrolo[1,2-a]benzimidazoles
Authors: Abe Noritaka , Ishikawa Naomi , Hayashi Takashi , Miura Yoshiaki
Published: July 2006

2-Chlorocyclohepta[b]pyrroles reacted with o-phenylenediamine to give 2-(2-aminoanilino)cyclohepta[b]pyrroles (2a,b) in good yields. Treatment of 2a and 2b with polyphosphoric acid afforded cyclohepta[1′,2′: 4,5]pyrrolo[1,2-a]benzimidazole (4a) in good yields. Treatment of 2b with acids gave 6-(ethoxycarbonyl) derivatives (4b) of 4a and 12H-5,13-dihydrocyclohepta[1′,2′: 4,5]pyrrolo[2,3-b][1,5]benzodiazepin-12-one (5). Compound 5 was methylated with methyl iodide in the presence of DBU to give 5H-12-methoxycyclohepta[1′,2′: 4,5]pyrrolo[2,3-b][1,5]benzodiazepine, a novel 20π antiaromatic system. Treatment of 2b with sodium ethoxide gave 4b and 2H-1-(cyclohepta[b]pyrrol-2-yl)-1,3-dihydrobenzimidazol-2-one (7a). Compound 5 rearranged to 7a in the refluxing sodium ethoxide-ethanol solution. Reactions of 2a and 2b with triethyl orthoformate gave corresponding 1-(cyclohepta[b]pyrrol-2-yl)benzimidazoles. Reactions of 2a and 2b with acetic anhydride are also mentioned.
Pressure-Accelerated Diels–Alder Reactions of Tropones with Aromatic p-Quinones
Authors: Mori Akira , Li Zhi-Hong , Nakashima Hisataka , Takeshita Hitoshi
Published: July 2006

The Diels–Alder reactions of tropones with aromatic p-quinones under 3000 and 10000 bar gave enolized 1:1-adducts together with dehydrogenated products, homobarrelenone derivatives. The latter were isomerized to tetracyclo[6.5.0.01,9.05,9]trideca-2,6,11-triene-4,10,13-triones on exposure to diffused light. No cycloadduct was obtained when the reaction was carried out under 1 bar.
Partial Molar Volumes in Aqueous Mixtures of Nonelectrolytes. IV. Aromatic Hydrocarbons
Authors: Sakurai Masao
Published: July 2006

The densities of binary mixtures of water with benzene, toluene, and ethylbenzene were measured for both ends of the concentration range at 5, 15, 25, 35, and 45 °C. The partial molar volumes were evaluated for both components by assuming a linear correlation of the density with the concentration. The partial molar volumes of the aromatic hydrocarbons (VA) in a water-rich region are smaller than the molar volumes of the respective solutes, but the temperature dependences of the VA are almost the same as the molar expansibilities of the solutes. On the other hand, the partial molar volumes of water (VW) and their temperature dependences in a hydrocarbon-rich region are appreciably larger compared with the molar volume and molar expansibility of pure water, respectively. The results are discussed on the basis of the scaled particle theory and interpreted in terms of the difference of the compressibilities of the solvents. The volumetric behavior of the aromatic hydrocarbons in aqueous solutions does not bear out any influence of a so-called iceberg structure.
Synthesis and Characterization of Polyyne Porphyrins
Authors: Maruyama Kazuhiro , Kawabata Shigeki
Published: July 2006

A series of conjugated polyyne porphyrins, in which two porphyrin macrocycles are connected with both ends of diarylpolyyne through aromatic ring, has been prepared and their spectroscopic behaviors were investigated. Diarylpolyyne consisting of aryl group and conjugated triple bond system have rigid and linear structure, and the two porphyrins are held at a fixed geometry and a determined distance. In their absorption spectra, porphyrin Soret bands were red- or blue-shifted depending on their edge-to-edge or face-to-face orientation.
Opioid Activities of Morphiceptin Analogs Derived from Human β-Casein
Authors: Sakaguchi Kazuyasu , Sakamoto Hiroshi , Tsubaki Yoshiko , Waki Michinori , Costa Tommaso , Shimohigashi Yasuyuki
Published: July 2006

Four tetrapeptide amides with the N-terminal Tyr–Pro sequence were synthesized as possible opioid agonists that can be produced by degradation of human β-casein. When these peptides were tested for their ability to bind to the μ and δ opioid receptors in rat brain, only H–Tyr–Pro–Phe–Val-NH2 was active, showing the 60% increased affinity for the μ receptors as compared with morphiceptin (H–Tyr–Pro–Phe–Pro–NH2) derived from bovine β-casein. It was highly μ-selective, as well as morphiceptin, with the μ/δ-selectivity ratio of 285. Other three analogs, H–Tyr–Pro–Ser–Phe–NH2, H–Tyr–Pro–Val–Arg–NH2 and H–Tyr–Pro–Val–Pro–NH2, were almost completely inactive. These results suggested that, for the morphiceptin-like tetrapeptide amides, the presence of Phe at position 3 is essential to elicit an activity to bind to the μ opioid receptors. Conformational considerations by measuring the CD spectra indicated that the sequence of tetrapeptide amide Tyr–Pro–Xxx–Pro(or Val)–NH2 is an important structural requirement to interact with the μ opioid receptors.
Synthetic Study on Peptide Antibiotic Nisin. IV. Synthesis of Ring D–E
Authors: Fukase Koichi , Oda Yoshiaki , Kubo Akira , Wakamiya Tateaki , Shiba Tetsuo
Published: July 2006

In the series of synthetic study on peptide antibiotic nisin, a bicyclic sulfide part ring D–E in this molecule was successfully synthesized. Conjunctive sulfide rings were constructed either by one step or stepwise desulfurization reaction from corresponding disulfides by use of hexaethylphosphorus triamide. Thus, all of the ring moieties in nisin were prepared for total synthesis of this antibiotic.
The Reaction of Three Sesquiterpene Ethers with m-Chloroperbenzoic Acid
Authors: Tori Motoo , Sono Masakazu , Asakawa Yoshinori
Published: July 2006

Three sesquiterpene ethers, guaioxide, a guaiane-type sesquiterpene ether (LB), and maalioxide have been subjected to reaction with m-chloroperbenzoic acid in chloroform under reflux. Guaioxide afforded four tertiary alcohols, while other two gave secondary alcohols. Structures of the products were determined by spectral data and chemical correlations.
Effects of Various Gas-Pretreatments of the Fe Powder, Prepared by the Reduction of FeI2 with Potassium Metal, on the Catalytic Properties in Fischer–Tropsch Synthesis
Authors: Miyake Mikio , Hamaguchi Maki , Nomura Masakatsu , Shimada Hiromichi , Nishijima Akio
Published: July 2006

Fischer–Tropsch (F–T) synthesis was carried out on the Fe powder catalyst prepared by the reduction of FeI2 with potassium metal in refluxing tetrahydrofuran (THF). 1-Butene was obtained with 37 wt% selectivity and a rather high conversion of 12 wt% by an autoclave system at 553 K. After H2-pretreatment of the Fe powder at 573 K, propylene was produced as the major product (15 wt% selectivity) under otherwise the same experimental conditions. In a conventional flow system with a stream of H2, H2/CO, and CO during a heatup period of the reactor to 533 K, C3, C4, and C5 olefins were produced as major products, respectively. The synthesized Fe powder contains 1.6 wt% of carbon, which may be produced by the decomposition of THF in preparation of the catalyst. During the gas-pretreatment of the Fe powder in the flow reactor, evolution of CH4 CO2, and CO was observed. The amount of carbon on the Fe powder produced after the gas-pretreatment varied with the pretreatment gas in the order, CO > H2/CO > H2. Quantitative X-ray photoelectron spectroscopy (XPS) analysis of the Fe powder surfaces indicates that a significant amount of carbonaceous species is accumulated during the F–T reaction, and that the accumulation of such species can be avoided by the H2-pretreatment of the Fe powder. The change in surface properties by the gas-pretreatments is discussed in relation to the corresponding change of the product distribution in the F–T synthesis.
Energetics of Silver Alloys. Enthalpies of Mixing and Formation in the Systems Silver–Aluminium and Silver–Tin
Authors: Badawi Walid , El-Talbi Mohamed , Oun Ahmed M
Published: July 2006

The paper presents values of the enthalpies of mixing and formation in the systems Ag–Al and Ag–Sn. Appropriate polynomial functions for the composition dependence of the enthalpies of mixing and formation and their partial molar quantities are given. The behaviors of the integral and partial molar enthalpies of mixing and formation are discussed. The trend of the enthalpy of formation in the system silver–tin points out the existence of the compound Ag–Sn in the solid state. The enthalpy of formation in the system Ag–Sn depends insignificantly on the temperature, while that in the system Ag–Al displays a pronounced temperature dependence which is attributed to lattice defects in the structure. A pronounced temperature dependence of the enthalpy of formation seems, therefore, not to be a general property of all metallic alloys.
Catalytic Oxidation–Reduction Hydration of Olefin with Molecular Oxygen in the Presence of Bis(1,3-diketonato)cobalt(II) Complexes
Authors: Kato Koji , Yamada Tohru , Takai Toshihiro , Inoki Satoshi , Isayama Shigeru
Published: July 2006

In the presence of a bis(1,3-diketonato)cobalt(II) complex, various olefins are converted to the corresponding hydrated products according to the Markownikov rule on treatment with molecular oxygen in secondary alcohol (“oxidation–reduction hydration”). Removal of water formed during the hydration reaction, especially by azeotropic method, is remarkably effective to improve yields of the hydrated products based on the cobalt(II) catalyst as bis(trifluoroacetylacetonato)cobalt(II) (Co(tfa)2) or bis(2-ethoxycarbonyl-3-oxobutanalato)cobalt(II) (Co(ecbo)2).
The Oxidation of 2,6-Di-tert-butyl-4-methylphenol Using Hydrogen Peroxide-Heteropolyacid System
Authors: Shimizu Masao , Orita Hideo , Hayakawa Takashi , Watanabe Yoshihito , Takehira Katsuomi
Published: July 2006

The oxidation of 2,6-di-tert-butyl-4-methylphenol (1) with hydrogen peroxide in the presence of heteropolyacids was carried out in acetic acid to give 2,6-di-tert-butyl-4-hydroperoxy-4-methyl-2,5-cyclohexadien-1-one (2), 2,6-di-tert-butyl-4-hydroxy-4-methel-2,5-cyclohexadien-1-one (3), and 2,6-di-tert-butyl-p-benzoquinone (4). Conversion of 2 into 4 under acidic conditions suggests that 2 could be a precursor of 4. The oxidation mechanism of phenols was discussed based on isolated intermediates.
Stereoselective Synthesis of (E)-2-Hydroxyimino-2-phenylacetonitrile by Photolysis of 4-Azido-3-phenylfurazan 2-Oxide
Authors: Kunai Atsutaka , Doi Takanori , Nagaoka Takashi , Yagi Hirofumi , Sasaki Kazuo
Published: July 2006

Synthesis of (E)-2-hydroxyimino-2-phenylacetonitrile from styrene was examined. This compound was obtained selectively by the photolysis of 4-azido-3-phenylfurazan 2-oxide.
Systematic Enumerations of Compounds Derived from D3h Skeletons. An Application of Unit Subduced Cycle Indices
Authors: Fujita Shinsaku
Published: July 2006

The table of unit subduced cycle indices (USCIs) for D3h is constructed and applied to the enumerations of chemical structures by starting from various parent skeletons of D3h symmetry i.e., a trigonal bipyramid, an iceane skeleton, and a pirsmane skeleton. The substitution positions of these skeletons are divided into orbits governed by coset representations. According to the division of such a skeleton, subduced cycle indices (SCIs) are constructed to enumerate chemical structures with respect to their symmetries. The introduction of figure inventories into the SCIs and the subsequent expansion give generating functions for counting fixed points. The resulting matrix of fixed points is multiplied by the inverse of a mark table to afford the number of isomers with each molecular formula and each subsymmetry.
Activation Process of CuY Zeolite Catalyst Observed by TPR and EXAFS Measurements
Authors: Tanabe Shuji , Matsumoto Hiroshige
Published: July 2006

EXAFS measurements have been employed to investigate structural changes of Cu species in Y-zeolite during TPR process. The formation of an active species by a consecutive reduction-reoxidation treatment was clearly demonstrated in the TPR spectra. Detailed analysis of the EXAFS data suggested that at a considerably low temperature the active species was reduced directly to Cu metal with a particle size of 5–8 Å, while at higher temperatures the original Cu2+ ions were reduced by a two-step mechanism, via Cu+ ions to Cu metal. From these points of view, the active species is considered to be small clusters of CuO with several Cu atoms.
Fluorometric Determination of Ethylenediamine Using a Beryllium-Schiff Base Complex
Authors: Aoki Izuo , Takahashi Akira , Watanabe Kunihiro
Published: July 2006

Ethylenediamine (en) reacts with salicylaldehyde and beryllium(II) in a weakly basic solution to form a fluorescent beryllium(II)-Schiff base complex. A fluorometric method for the determination of en by using the beryllium(II) complex has been established. Ethylenediamine could be determined in 2×10−7–2×10−5 mol dm−3 within a relative standard deviation of 3%. The detection limit of en was 8×10−9 mol dm−3. Ammonia, diethylamine, and triethylamine does not interfere with the determination of en. The present method has been applied to the analysis of en in aminophylline tablets. The fluorometric method for the determination of trace amount of amino acid by using an aluminum(III)-Schiff base complex has also been investigated.
Selectivity of Coordination Sites in Ni(II), Zn(II), and Cd(II) Complexes with 7-[(3,5-Dichloro(or bromo)-2-pyridyl)azo]-8-hydroxyquinoline-5-sulfonic Acid
Authors: Huang Hu , Chikushi Hiroaki , Nakamura Masaaki , Kai Fumiaki
Published: July 2006

A new multidentate ligand, 7-[(3,5-dichloro(or bromo)-2-pyridyl)azo]-8-hydroxyquinoline-5-sulfonic acid (sodium salt, abbr. as 3,5-di-X-PAHQS, X=Cl or Br) which contains pyridylazonaphthol (PAN) and 8-quinolinol skeletons, was prepared for the first time in order to investigate its coordination behavior toward metal(II) ions. For comparative studies, the ligands (2-[(3,5-dichloro(or bromo)-2-pyridyl)azo]-1-hydroxynaphthalene-4-sulfonic acid (sodium salt, abbr. as 3,5-di-X-αPANS, X=Cl or Br), 1-[(3,5-dichloro(or bromo)-2-pyridyl)azo]-2-hydroxynaphthalene-6-sulfonic acid (sodium salt, abbr. as 3,5-di-X-βPANS, X=Cl or Br), and 7-[(4-chloro or unsubstituted phenyl)azo]-8-hydroxyquinoline-5-sulfonic acid(sodium salt, abbr. as 4-Cl-BAHQS for chloro substituted phenyl and BAHQS for unsubstituted phenyl, respectively)) were also prepared. The coordination modes of the synthesized multidentate ligands with Ni(II), Zn(II), and Cd(II) ions were investigated both spectrophotometrically and polarographically, in aqueous solution. Judging from the variations of the reduction potentials of the azo group with metal complexations, in the case of the ligands of BAHQS systems, the azo group did not participate in complexation. On the contrary, for the ligands of the PAN and PAHQS systems, the azo group in these ligands clearly participated in metal-complexation. On the basis of the results of polarographic studies and of spectral data, the complexing equilibria of these complexes were analyzed and the stability constants calculated. The dissociation constants and the reduction potentials of these new ligands are also discussed.
ESR Studies of the Competitive Adsorption Behavior of Poly(methyl methacrylate) and Polystyrene Mixtures at the Solid–Liquid Interface
Authors: Kobayashi Kazutoshi , Sugimoto Shizuo , Yajima Hirofumi , Araki Kazuo , Imamura Yoshio , Endo Ryuichi
Published: July 2006

The adsorption from solution of polystyrene and poly(methyl methacrylate) mixtures on a silica surface was studied in order to establish the competitive adsorption behavior of these polymers. The fractions of train segment for these polymers were determined from the ESR spectra analyses, and these values were compared with those of the individual adsorption. When the initial concentrations of the polymer mixtures in solution were fixed and the added amounts of silica adsorbent were varied, the adsorption of polystyrene did not take place until the poly(methyl methacrylate) in solution was completely exhausted. In the simultaneous adsorption, the amount of adsorption of poly(methyl methacrylate) was affected by the presence of polystyrene in the solution. On the other hand, the amount of adsorption of polystyrene was unaffected by the presence of poly(methyl methacrylate) in the system. The conformation of the adsorbed poly(methyl methacrylate) was also affected by the presence of polystyrene when they were simultaneously adsorbed on the silica surface. The conformation of the poly(methyl methacrylate) adsorbed from the mixed solution formed a more compressed polymer layer in comparison with that for the case where the poly(methyl methacrylate) was adsorbed alone.
The Creation of a Skin-Core Structure in Petroleum Derived Mesophase Pitch Based Carbon Fiber
Authors: Zeng Shu-Ming , Korai Yozo , Mochida Isao , Hino Takashi , Toshima Hiroshi
Published: July 2006

Stabilization of a petroleum-derived mesophase pitch (P-MP) fibers was investigated in order to create a skin-core structure in the carbonized fibers. The pitch fibers were either oxidatively stabilized at 270°C in air or 10 vol% O2 for short periods, or oxidized in air for 15 min and successively extracted by tetrahydrofuran (THF) for 30 min. A skin-core structure could be observed in the carbonized fibers under a polarized-light microscope or SEM. The relationship between the oxidative reactivity of P-MP fiber and creation of a skin-core structure, and the effect of solvent extraction for the creation are discussed according to the results.
Synthesis of Nickel and Magnesium Phyllosilicates with 1:1 and 2:1 Layer Structures
Authors: Mizutani Tadashi , Fukushima Yoshiaki , Okada Akane , Kamigaito Osami
Published: July 2006

Nickel and magnesium phyllosilicates with 1:1 and 2:1 layer structures were prepared from silicic acid and metal chlorides (NiCl2 or MgCl2) in water. The phyllosilicates were allowed to crystallize at room temperature or 200°C. The 1:1 and 2:1 phyllosilicates were selectively prepared by adjusting the metal ion to silicon ratio (M/Si) in the starting mixtures. The 1:1 phyllosilicate was crystallized from the starting mixture with an M/Si ratio of 1.5 and the 2:1 phyllosilicate was crystallized from the mixture with an M/Si ratio of 0.5. The increase in the OH−/M ratio in the starting mixture accelerated the crystallization to phyllosilicates. Crystallization to the phyllosilicates occurred even at room temperature, and a hydrothermal treatment at 200°C accelerated this process. The crystal size of the 1:1 phyllosilicates was larger than that of the 2:1 phyllosilicates. The nickel phyllosilicates crystallized faster than the magnesium phyllosilicates. These results can be explained by assuming successive copolymerization reactions of silicic acid and aqua metal ions, in which an intermediate with a 1:1 structure is involved. The acidity of the aqua metal ions plays an important role in the mechanism of the copolymerization process.
Preparation of 1-Aryl- or 1-Alkenyl-2-(perfluoroalkyl)acetylenes
Authors: Yoneda Norihiko , Matsuoka Shigeru , Miyaura Norio , Fukuhara Tsuyoshi , Suzuki Akira
Published: July 2006

1-Aryl- or 1-alkenyl-2-(perfluoroalkyl)acetylenes were produced in high yields by the coupling reaction of aryl or alkenyl iodides with (perfluoroalkynyl)zinc compounds prepared from the corresponding (perfluoroalkyl)acetylenes in the presence of Pd catalyst.
Miscibility of 1-Octanol and 2-(Octylsulinyl)ethanol in the Adsorbed Film and Micelle
Authors: Matsuki Hitoshi , Kanda Tomoko , Aratono Makoto , Motomura Kinsi
Published: July 2006

The surface tension of the aqueous solution of 1-octanol and 2-(octylsulfinyl)ethanol (OSE) mixture was measured as a function of the total molality of surfactants and the composition of OSE in the total surfactants at 298.15 K under atmospheric pressure. It was observed that 1-octanol molecules form mixed micelles with OSE molecules in the composition range above 0.850. The corresponding composition in the mixed adsorbed film was evaluated numerically by applying the thermodynamic relations developed previously. It was found that the surfactant molecules mix with each other in all proportions in the adsorbed film and the composition in the adsorbed film is smaller than that in the solution. Further, the adsorbed film was found to be richer in 1-octanol than the micelle at the critical micelle concentration (cmc). This behavior was attributed to the fact that 1-octanol is more surface active than OSE though it does not form the micelle.
Photoelectron Spectra of Polypyrrole: The Effect of the Ambient Atmosphere to the Spectra
Authors: Hino Shojun , Iwasaki Kentaro , Tatematsu Hideki , Matsumoto Kazuo
Published: July 2006

Ultraviolet and X-ray photoelectron spectra of carefully prepared undoped as well as doped polypyrrole have been measured. Reliable UPS of undoped polypyrrole must be the first one in spite of its popularity, because of its instability in the air. Our UPS were compared with those of presumably polymerized pyrrole by X-ray irradiation and other reported results. We examined the validity of these spectra and we found the deformation of the UPS caused by air exposure of the undoped film. A comparison of our UPS with theoretical calculation gave 1.40 Å as an estimated bond distance between α,α′ carbon atoms. Both Cls and Nls XPS were asymmetric and consisted of a few peak components, which was not dependent on doping. Their peak envelopes varied with its historical back ground. While the Cls peak envelopes were not deformed so seriously by air exposure, the Nls envelopes were affected by slight air exposure as were observed in the UPS.
Synthesis, Structure, and Magnetism of Binuclear Cu(II)Cu(II), Cu(II)Ni(II), and Ni(II)Ni(II) Complexes Doubly Bridged by Oxymate Groups
Authors: Luneau Dominique , Oshio Hiroki , Okawa Hisashi , Koikawa Masayuki , Kida Sigeo
Published: July 2006

Binuclear complexes, [Cu(L)Cu(L′)(H2O)2]X2 (H2L=3,3′-trimethylenedinitrilobis(2-butanoneoxime) (H2dopn) or 3,3′-ethylenedinitrilobis(2-butanoneoxime) (H2doen); L′=2,2′-bipyridyl (bpy) or 1,10-phenanthroline (phen); X=ClO4 or NO3), [Ni(dopn)Cu(bpy)(H2O)](ClO4)2, and [Ni(dopn)Ni(bpy)2](ClO4)2, have been prepared and characterized. The structure of [Cu(dopn)Cu(phen)(CH3OH)2](ClO4)2 (di-methanol adduct) has been determined by single crystal X-ray method. The Cu(dopn) molecule coordinates to the second copper(II) ion through the deprotonated oximate oxygens to afford a binuclear structure doubly bridged by the oximate groups in the cis arrangement. The binuclear cation is bent at the oxymate oxygens with a dihedral angle of 26.7(2)°. The binuclear copper(II) complexes show a characteristic visible band of significant intensity (ε 2700–2900 dm3 mol−1cm−1) near 22000 cm−1 and a strong intramolecular antiferromagnetic spin-exchange interaction. The exchange integrals (J) are evaluated to be −413.3–−433.0 cm−1. The magnetic moment (per molecule) of the nickel(II)–copper(II) complex is 1.80 μB at room temperature and the moment of the binuclear nickel(II) complex is 2.94 μB, demonstrating that the Ni(dopn) entity of these complexes is diamagnetic.
Et3B Induced Stereoselective Radical Addition of Ph3GeH to Carbon–Carbon Multiple Bonds and Its Application to Isomerization of Olefins
Authors: Nozaki Kyoko , Ichinose Yoshifumi , Wakamatsu Kuni , Oshima Koichiro , Utimoto Kiitiro
Published: July 2006

Triphenylgermane easily adds to acetylenes or terminal olefins in the presence of Et3B to give alkenyltriphenylgermane or alkyltriphenylgermane respectively under excellent control of regio- and stereoselectivities. While Et3B catalyzed addition of Ph3GeH to 1-dodecyne at −78 °C affords (Z)-1-triphenygermyl-1-dodecene exclusively, the addition of Ph3GeH at 60 °C provides (E)-1-triphenylgermyl-1-dodecene as a single product. The triphenylgermyl radical is also effective to isomerize Z-olefins into their thermodynamically more stable E-isomers.
Effects of Branching of the Ester Alkyl Chain on the Mesomorphic Properties of Alkyl 4-[4-(4-Substituted benzoyloxy)benzylideneamino]benzoates
Authors: Matsuzaki Hiroyuki , Matsunaga Yoshio
Published: July 2006

The mesomorphic properties of five homologous series of alkyl 4-[4-(4-X-substituted benzoyloxy)benzylideneamino]benzoates, where X=CN,NO2, CH3, Cl, and CH3COO, have been studied. The ester alkyl groups employed were the following eleven types: ethyl and propyl and their mono-, di-, and trimethyl-substituted ones. Although the introduction of the first branching methyl group to the ester alkyl chain depresses the nematic stability, the second and/or third groups may either further depress or enhance the stability, depending upon the nature of the substituent X. While all of the members of the cyano and nitro derivatives are purely nematogenic, many members of the other three series display a smectic A phase, as well as a nematic phase. In addition to the above-mentioned esters, the butyl, pentyl, and their monomethyl-substituted esters were examined in order to demonstrate that the effects on the thermal stability of the smectic A phase of the branching of the ester alkyl chain and those of the substituent X are also interdependent.
Functionalized Bilayer Membranes as Artificial Tryptophan Synthase. Characterization of Catalytic Efficiency, Substrate Specificity, and Reaction Selectivity
Authors: Murakami Yukito , Kikuchi Jun-ichi , Hisaeda Yoshio , Nakamura Koichiro , Kitazaki Tomoyuki , Kaya Hidenori
Published: July 2006

Functionalized bilayer membranes having vitamin B6 activity effectively catalyzed β-replacement reactions of serine with indoles to afford the corresponding tryptophan derivatives in aqueous media under mild conditions. Catalytic capability of the present artificial enzyme was subjected to change by changing a combination of molecular components constituting the catalyst system. The structural mode of a hydrophobic pyridoxal derivative as the coenzyme model, the catalytic ability of an amino acid residue placed in a peptide lipid which forms single-walled bilayer vesicles as the apoenzyme model, and the coordination property of added metal ions were found to be responsible for the overall catalytic performance. Multifunctional assistance was observed in the β-replacement reaction of serine with indole, and the reaction proceeded in preference to other side reactions, such as β-elimination, dealdolation, and transamination reactions. Substrate selectivity was found to be primarily dependent on the nucleophilicity of indole derivatives.
Fading Mechanism of Paint Films Composed of Insoluble Azo Pigment and Titanium Dioxide
Authors: Okamoto Shingo , Ohya-Nishiguchi Hiroaki
Published: July 2006

The fading mechanism of paint films comprising an insoluble azo pigment and titanium dioxide was investigated using ESR and FT-IR spectrometers and the results of outdoor exposure tests. Some paramagnetic species were found in paint films at room temperature. They showed no hyperfine structure and their g-values drastically changed according to sample preparation, the measurement temperature and treatments with a base or acid. These paramagnetic species are proposed to be O2− in an adsorbed state on a TiO2 surface and O− of the TiO2+. It is suggested that film fading occurs through an attack of these active oxygens on the insoluble azo pigment.
Methoxybromination of Cinnamic Acid by N-Bromosuccinimide
Authors: Karunakaran C , Venkatachalapathy C
Published: July 2006

With cinnamic acid in aqueous methanol N-bromosuccinimide yields 2-bromo-3-methoxy-3-phenylpropionic acid. It is a second-order reaction independent of [H+] at moderately high [H+]. At low [H+] the rate increases with decrease in [H+]. The reaction is inhibited by succinimide. The reaction rate decreases with increase in methanol content of the medium. Mechanistic pathways of the reaction are discussed and a rate equation is derived.
Oxidation of Aromatic Alcohols with Chromium(VI) Trioxide in the Presence of “Wet-Aluminium Oxide” in Aprotic Solvent
Authors: Hirano Masao , Kuroda Hisanori , Morimoto Takashi
Published: July 2006

The title oxidation resulted in a selective formation of the corresponding carbonyl compounds in excellent yields under mild conditions.
Crystal Structure of 4,4′,5,5′-Tetrachloro-2,2′-bi-1,3-dioxolane
Authors: Huang Hsing Hua , Ogata Koreharu , Sakai Shin-ichiro , Sim Keng Yeow
Published: July 2006

The main product, A obtained from the interaction of concentrated sulfuric acid with trans-2,3-dichloro-1,4-dioxane has been shown by a single crystal X-ray structure analysis to be the trans–trans  meso-stereoisomer of 4,4′, 5,5′-tetrachloro-2,2′-bi-1,3-dioxolane.
Electrochemical Reduction of Carbon Dioxide at Various Metal Electrodes in Aqueous Potassium Hydrogen Carbonate Solution
Authors: Noda Hidetomo , Ikeda Shoichiro , Oda Yoshiyuki , Imai Kazumoto , Maeda Masunobu , Ito Kaname
Published: July 2006

The electrochemical reduction of carbon dioxide at various metallic electrodes was carried out potentiostatically at 298 K in aqueous potassium hydrogen carbonate solution in order to make clear the electrocatalysis of metals in reduction of CO2. It was found that metals used as electrodes are classified into four groups according to their main products from CO2, i. e., metallic In, Sn, Hg, and Pb are selective for the production of formic acid; metallic Ag and Au are selective for the formation of carbon monoxide; metallic copper has the highest electrocatalytic activities in formation of hydrocarbons, aldehydes, and alcohols; and metallic Al, Ga, Group a, and Group VIII elements except Pd have scarce electrocatalytic activity in reduction of CO2. Effects of the reduction potential on products from CO2 were also examined in detail for Zn, In, and Au electrodes which have some interesting properties.
Spin Trapping as Applied to Radicals Produced by the Thermal Decomposition of Di-t-butyl Diperoxyoxalate (DBPO) in Aromatic Hydrocarbons
Authors: Sueishi Yoshimi , Furui Seiji , Matsumoto Yukinobu , Yamamoto Shunzo , Nishimura Norio
Published: July 2006

Di-t-butyl diperoxyoxalate (DBPO) was allowed to decompose at 40 °C in benzene and xylenes, and transient radicals were trapped by some nitroso compounds. By means of an ESR simulation technique, the trapped radicals were assigned. In benzene, t-butoxyl radicals were trapped. Exceptionally, when 1,3,5-tri-t-butyl-2-nitrosobenzene(1) was used, methoxyl radicals were trapped first, but the ESR signals changed with time and methyl radicals were finally trapped. In xylenes, monomethylbenzyl radicals were exclusively trapped by 1 and 2,4,6-trimethyl-l-nitrosobenzene(2). The hyperfine coupling constant (hfcc) of β-hydrogens exhibited a negative temperature dependence for adducts formed between 1 and benzyl radicals(1-BZ), while for adducts formed between 2 and benzyl radicals(2-BZ), a positive one.
Parametrized Equations-of-Motion Method at the (1p-1h)+(2p-2h) Level. II. Simplified Treatment of σ–π Correlations
Authors: Shibuya Tai-ichi , Narita Susumu
Published: July 2006

The previously proposed scheme of parametrized equations of motion for the π→π* transitions of linear polyenes [Bull. Chem Soc. Jpn., 62, 701 (1989)] has been simplified in the treatment of the σ–π electron correlations. The simplified schemes seem to give results as accurate as the original one for the low-lying excited states.
A New Apparatus for Simultaneous Measurement of Acoustic Emission and Differential Thermal Analysis and Its Application to Dehydration, Phase Transition, and Decomposition Studies of Several Inorganic Salts
Authors: Shimada Shiro , Furuichit Ryusaburo
Published: July 2006

A new apparatus for simultaneous measurements of acoustic emission (AE) and differential thermal analysis (DTA) is described. Two fused silica cells are used as the sample and reference holders and a fused silica rod, fixed at the bottom of the sample holder, acts as the waveguide for AE signals emitted in the sample. A 140 KHz resonance frequency sensor is attached at the end of the rod to detect the AE signals which are converted by an AE tester to three parameters, the wave form, the event count rate, and the cumulative count. The technique has been successfully utilized to study the dehydration, phase transition, and decomposition of NaN3, KNO3, KClO4, CaCrO4·0.1H2O, and MgCl2· 6H2O, for which the interesting results are reported.
Syntheses and Reactions of Conjugated Dienic Thioketones
Authors: Moriyama Satoshi , Karakasa Takayuki , Motoki Shinichi
Published: July 2006

5,6-Dihydro-2-phenyl-3-thiobenzoyl-2H-naphtho[1,2-b]thiin (8a) and the related dienic thioketones were synthesized in 3 steps starting from 2-(phenylthio)methylenetetralin-1-thione with chalcone, 4′-chrolochalcone, 4′-methoxychalcone, 2-cinnamoylthiophen, 2-cinnamoylfuran, 1-phenyl-2-buten-1-one, and acrylophenone respetively. Similarly, 3-thiobenzoyl-2,6-diphenyl-2H-thiin (8i) was synthesized from 1-phenyl-3-phenylthio-2-propene-1-thione. All of these dienic thioketones were found to exist in stable monomeric form. The conjugated dienic thioketone (8a) reacted as α,β-unsaturated thioketone with 2-norbornene, 2,5-norbornadiene, diethyl azodicarboxylate, diphenyl fumarate, N-phenyl- and N-(p-tolyl)maleimides, 2-chloroacrylonitrile, methyl methacrylate, acrylonitrile, and styrene to give the corresponding [4+2]cycloadducts. The thioketone (8i) also reacted with 2-norbornene to give the corresponding cycloadduct. The reaction provides a useful method for the syntheses of various sulfur-containing heterocycles.
Liquid-Phase Oxidative Lactonization of Butane-1,4-diol into γ-Butyrolactone with Oxygen over Palladium Supported on K-L Zeolite
Authors: Baba Toshihide , Kameta Keiichiro , Nishiyama Satoru , Tsuruya Shigeru , Masai Mitsuo
Published: July 2006

Pd0 supported on K-L zeolite suspended in a liquid phase has a high catalytic activity and a high selectivity for the oxidative lactonization of butane-1,4-diol into γ-butyrolactone under oxygen at 391 K.
Alkylation of Several Nucleophiles with Alkylsulfonium Salts
Authors: Umemura Kazuyuki , Matsuyama Haruo , Kamigata Nobumasa
Published: July 2006

The reactions of dialkylphenylsulfonium salts (1) with several nucleophiles such as phenols, amine, enolate ion, and thiolate ions, have been investigated. The relative reactivities of the alkyl groups of sulfonium salts for the phenolate ion (hard nucleophile) were as follows; Me:Et:i-Pr =1.0:1.34:3.44. In the alkylation of the p-toluenethiolate ion (soft nucleophile) with 1, the opposite reactivity (Me:Et:i-Pr=1.0:0.22:0.03) was found. When a sulfonium salt (1e) having an optically active (S)-s-butyl group was reacted with a phenolate ion, an optically active (R)-s-butyl phenyl ether was obtained with an inversion of the configuration at the chiral carbon atom. A reaction mechanism via a sulfurane intermediate is proposed for the alkylation of the phenolate ion with alkylsulfonium salts. The relative reactivities for the alkylation of several nucleophiles with dialkylphenylselenonium salts (12) were also investigated.
Ultrasonic Study in Aqueous Solutions of Alcohols with Methoxyl and Propoxyl Groups
Authors: Nishikawa Sadakatsu , Moritsubo Yumiko , Matsuo Fumiharu , Endo Yosiaki
Published: July 2006

Ultrasonic absorption, velocity and density measurements were carried out in aqueous solutions of 1-methoxy-2-propanol and 3-(3-methoxypropoxy)propanol as a function of their concentrations at 25°C. A single ultrasonic relaxational phenomenon was observed in both solutions in the frequency range from 6.5 to 220 MHz. The cause was attributed to a perturbation of an equilibrium associated with the solute solvent interaction, AB(Remark: Graphics omitted.)A+B, from the concentration dependences of the relaxation frequency and the amplitude of the relaxational absorption. The rate and thermodynamic parameters were determined for the above process. It was found that the methoxyl group introduced in alcohol molecule acted as a water structure breaker while the propoxyl group promoted the water structure. Speculation of excess ultrasonic absorption in various monohydroxy alcohol aqueous solutions was carried out from the present data. In order to further confirm the participation of the solvent water molecule in the observed relaxation process, absorption measurements were carried out in methanol, dimethyl sulfoxide, and their mixed solvents with water for 3-(3-methoxypropoxy)propanol.
The Synthesis of Transition-Metal Salts of 2-Oxo-1,3-dithiole-4,5-dithiolate (dmio)
Authors: Ikegawa Shunjiro , Nogami Takashi , Shirota Yasuhiko
Published: July 2006

Transition-metal salts of 2-oxo-1,3-dithiole-4,5-dithiolate (dmio) were synthesized in order to develop highly conducting organic complexes. Their redox potentials were measured and compared with those of the related 1,2-dithiolate salts.
Mechanisms and Rate Constants for the Quenching of Singlet Oxygen by Nickel Complexes
Authors: Shiozaki Hisayoshi , Nakazumi Hiroyuki , Takamura Yoshikazu , Kitao Teijiro
Published: July 2006

An iterative numerical determination of the rate constants for both quenching of, kq, and reaction with, kr, singlet oxygen by dithiolato nickel complexes is developed. This numerical method gives accurate rate constants for a small number of kinetic runs. The substituent effects of these complexes on rate constants lead us to conclude that the complexes quench singlet oxygen by an energy-transfer mechanism. This numerical method developed for solution systems was applied to the estimation of the photofading rate of a cyanine dye on an epoxy resin plate.