bluuebunny/crossref_metadata_2025 huggingface dataset:
1-3-η-Allylpalladium(II) and Platinum(II) Complexes Containing Tris(2,6-dimethoxyphenyl)phosphine Ligand
Authors: Kurosawa Hideo , Tsuboi Aki , Kawasaki Yoshikane , Wada Masanori
Published: July 2006

Neutral and cationic 1-3-η-(2-methylallyl) complexes of Pd and Pt containing tris(2,6-dimethoxyphenyl)phosphine (abbreviated as P(2,6)3), M(1-3-η-CH2CMeCH2)Cl{P(2,6)3} and [M(1-3-η-CH2CMeCH2){P(2,6)3}]BF4, were prepared. The latter contained a weakly coordinated OMe group of P(2,6)3 which was readily replaced by carbon monoxide to afford [M(1-3-η-CH2CMeCH2)(CO){P(2,6)3}]BF4. Owing to large steric bulk and high nucleophilicity of P(2,6)3, addition of P(2,6)3 to these complexes did not result in coordination of the second molecule of the phosphine to the metal atom but ready attack at the metal-bound 2-methylallyl and methoxyl carbon atoms to give the corresponding (2-methylallyl)phosphonium and methylphosphonium ions. From these reactions were isolated a neutral 1-3-η-(2-methylallyl)platinum(II) complex involving chelate coordination of a tertiary phosphine ligand which was derived from the loss of methyl of one methoxyl group in P(2,6)3 and the resulting phenoxo ligand, and a cationic, binuclear Pt(I) carbonyl complex bridged by the 2-methylallyl group. Also prepared in this study were 1-3-η-(2-methylallyl)(acetylacetonato) complexes of Pd and Pt, M(1-3-η-CH2CMeCH2)(acac){P(2,6)3}. In the platinum analog, the acetylacetonato ligand was suggested to coordinate to the metal in a monodentate fashion via the central carbon atom. Both complexes afforded moderate yields of CH2=CMeCH2CH(COMe)2 upon treatment with carbon monoxide, while the reaction of M(1-3-η-CH2CMeCH2)(CO){P(2,6)3}+ with sodium acetylacetonate failed to give the same coupling product.
Possible Fluorescence from the Polycyclic Aromatic Hydrocarbons in the Interstellar Medium
Authors: Aihara Jun-ichi
Published: July 2006

Large compact polycyclic aromatic hydrocarbons (PAHs) are photochemically very stable. These PAHs have been considered as excellent candidates for explaining the interstellar infrared emission lines. Since the large compact PAHs exhibit the first electronic absorption band in a rather low-energy region, it is possible and very probable that fluorescence from such PAHs are responsible for the red emission humps of several nebulae such as the Red Rectangle, a nebula surrounding the binary star HD 44179.
Alkaline Hydrolysis of N-Methyl-2,4-dinitroacetanilide and N-Alkyl-N-(5-nitro-2-pyridyl)acetamides
Authors: Kijima Atsushi , Sekiguchi Shizen
Published: July 2006

The kinetics of the alkaline hydrolysis of N-methyl-2,4-dinitroacetanilide (2), N-ethyl- (3), and N-methyl-N-(5-nitro-2-pyridyl)acetamide (4) was carried out. The reaction path consists of two stages: the first one is the rate-limiting formation of the first tetrahedral intermediate (monoanionic) and the second one the fast decomposition of the intermediate. The latter fast decomposition of the intermediate (monoanionic) involves two processes: one is the direct decomposition of the intermediate to the products and the other is a proton abstraction of the hydroxyl group of the intermediate by −OH giving the second tetrahedral intermediate (dianionic), followed by its deconposition to the products. For the alkaline hydrolysis of 2–4, the decomposition of the first intermediate occurred predominantly via the latter process.
Syntheses of Bis(vinylenedithio)tetrathiafulvalene and Bis(methylvinylenedithio)tetrathiafulvalene
Authors: Nakamura Tadashi , Iwasaka Shin-ichi , Nakano Hideyuki , Inoue Kazuhiko , Nogami Takashi , Mikawa Hiroshi
Published: July 2006

Bis(vinylenedithio)tetrathiafulvalene (BVDT-TTF) and bis(methylvinylenedithio)tetrathiafulvalene (BMVDT-TTF) were synthesized as attractive donor molecules for highly conductive organic salts. These molecules have analogous structures to BEDT-TTF, but are expected to possess more planar structures. They have higher oxidation potentials than BEDT-TTF. The synthetic method of BVDT-TTF by using a phase-transfer catalyst was also studied.
Molecular Recognition in the Formation of Conglomerate Crystal. The Role of Cinnamic Acid in the Conglomerate Crystals of 1-Phenylethylamine and 1-(4-Isopropylphenyl)ethylamine Salts
Authors: Saigo Kazuhiko , Kimoto Hiroki , Nohira Hiroyuki , Yanagi Kazunori , Hasegawa Masaki
Published: July 2006

The Crystal structures of (+)-1-phenylethylamine·cinnamic acid salt and (+)-1-(4-isopropylphenyl)ethylamine·cinnamic acid salt were determined by X-ray analysis. The crystal structures of these two salts provided for the first time some insights into the mechanism of the formation of a conglomerate crystal. In each crytal, two amine components and two acid components form a helical column by hydrogen bonds. On the basis of this similarity in the molecular arrangements, the role of cinnamic acid, an achiral acid, is discussed, and the criteria for the choice of an achiral acid in the transformation of the racemic modification of an amine into a conglomerate crystal is proposed.
Asymmetric Radical Reaction in the Coordination Sphere. III. Asymmetric Addition of Trichloromethanesulfonyl Chloride and Carbon Tetrachloride to Olefins Catalyzed by a Ruthenium(II) Complex with Chiral Ligand
Authors: Kameyama Masayuki , Kamigata Nobumasa
Published: July 2006

The asymmetric addition of trichloromethanesulfonyl chloride to styrene in the presence of a catalytic amount of a ruthenium(II) complex with chiral ligands, Ru2Cl4[(−)-diop]3 or Ru2Cl4[(+)-diop]3, proceeds under mild conditions to give optically active 1:1 adducts, 1,1,1,3-tetrachloro-3-phenylpropane (2), with the extrusion of sulfur dioxide. When (−)-DIOP or (+)-DIOP was used as a chiral ligand of the ruthenium(II) complex, (R)-(+)-(2) or (S)-(−)-(2), was obtained with about 10% enantiomeric excess, respectively. A reaction mechanism involving a radical redox transfer mechanism was proposed; the asymmetric induction was attributed to the restricted configuration of the radical intermediates confined in the coordination sphere of the ruthenium complex with chiral ligands.
A Convenient One-Pot Cyanosilylation of Aldehydes and Ketones Using Potassium or Sodium Cyanide Impregnated on Amberlite XAD Resin and Trimethylsilyl Chloride
Authors: Sukata Kazuaki
Published: July 2006

In the cyanosilylation of benzaldehyde, the combination of potassium or sodium cyanide impregnated on Amberlite XAD resin and trimethylsilyl chloride has been found to be a good one-pot cyanosilylation agent. Although acetonitrile is the best solvent, substantial yields of the product is obtained even in a nonpolar solvent or without any solvent. In the reaction with other aldehydes or ketones, this method gives the corresponding silylated cyanohydrins in extremely high yields.
Polymer-Protected Metal Complex for Gas Separation. III. Water-Resistivity of Polystyrene Resin-Supported Aluminium Copper(I) Chloride as Solid Carbon Monoxide Adsorbent
Authors: Hirai Hidefumi , Hara Susumu , Komiyama Makoto
Published: July 2006

Solid adsorbents of carbon monoxide are prepared from aluminium chloride, copper(I) chloride, and a macroreticular type polystyrene resin by use of various solvents, and their resistivities against water vapor are investigated. The adsorbing capacities of the adsorbents prepared by use of carbon disulfide and dichloromethane remain virtually unchanged even after repeated (3–5 times) contacts of the adsorbents with nitrogen gas containing 10 mol% water with respect to the charged copper(I) chloride (water contents: 5600 and 4600 ppm). The adsorbents obtained with the use of benzene and toluene as preparation solvents, however, exhibit small but gradual decreases in the adsorbing capacities on the repeated contacts with nitrogen gas containing water. Scanning electron microscopy and energy dispersive X-ray microanalysis on the water-resistant adsorbents, prepared with the use of carbon disulfide and dichloromethane, show that the active species for the adsorption, aluminium copper(I) chloride, uniformly distributes in the beads of the polystyrene resin without formation of aggregates. Almost all of aluminium copper(I) chloride is located in the apolar microporosities of the polystyrene resin here, and is effectively protected from water vapor.
Energetics of the Sequential Electroreduction and Electrooxidation Steps of Benzenoid Hydrocarbons
Authors: Kubota Tanekazu , Kano Kenji , Uno Bunji , Konse Tomonori
Published: July 2006

The first and second reduction (E1⁄2.1red, E1⁄2.2red) and the first oxidation (E1⁄2.1oxd) standard potentials of benzenoid alternant hydrocarbons (BAH) were experimentally determined by means of cyclic voltammetry (CV) in nonaqueous solvents. The second standard oxidation potential (E1⁄2.2oxd) was however, estimated by checking the scan rate dependence of the irreversible CV curve. The equations pertinent to these potentials and their mutual relations were formulated from the points of view of the Born–Haber-type thermodynamic energy cycle and SCFMO calculations. Of the SCFMO calculations, the MO-paring property established in the PPP-type π-electron theory was very successful in the discussion of the equations given above. Under the acceptable assumptions that the solvation energies due to mono- and dications are put equal to those of the mono- and dianions respectively, and using the MO-pairing property, the equation of (E1⁄2.1oxd+E1⁄2.1red)=(E1⁄2.2oxd+E1⁄2.2red) was derived. The experimental results were well described by this equation. The solvationenergy values were evaluated by applying the experimentally determined reduction or oxidation potentials to the theoretical equations. An examination of the solvation energies has shown that these values can be interpreted by means of the Born-type equation.
Entropy Changes in the Inclusion Complex Formation of α-Cyclodextrin with Alcohols as Studied by the Titration Calorimetry
Authors: Fujiwara Hideaki , Arakawa Haruyuki , Murata Saburo , Sasaki Yoshio
Published: July 2006

The inclusion complex formation of α-cyclodextrin(α-CD) with various alcohols has been studied by means of titration calorimetry. The titration curve was analyzed successfully by the formation of a 1:1 hostguest complex, and the thermodynamic parameters were determined. The entropies of reaction are estimated from the statistical thermodynamics of molecules. However, the estimated values are found to deviate by an order of magnitude from the experimental ones. To resolve such a discrepancy, α-CD in solution is assumed to include a definite number(n) of water molecules which are replaced by a guest molecule with the progress of reaction. The entropies thus estimated depend extensively on the value of n, and a value of n is determined for each alcohol so that it reproduces just the experimental entropy. The resulting n values are nearly constant for various alcohols studied and are within a reasonable range expected from the data reported in crystal, supporting the model of interpretation.
Optical Resolution of Alcohols as Carbamates by HPLC on Cellulose Tris(phenylcarbamate) Derivatives
Authors: Okamoto Yoshio , Cao Zun-Kui , Aburatani Ryo , Hatada Koichi
Published: July 2006

The optical resolutions of various alcohols as phenylcarbamates were examined by HPLC on chiral stationary phases derived from sixteen cellulose tris(phenylcarbamate) derivatives. The optical resolving power of chiral stationary phases was greatly influenced by substituents on the phenyl groups of the cellulose derivatives. Also, cellulose tris(3,5-dimethylphenylcarbamate) could very efficiently resolve many racemic phenylcarbamates, including the carbamates of 2-butanol, 3-buten-2-ol, and 1-phenylethanol. Racemic phenylcarbamates having electron-donating substituents on the phenyl group were better resolved than those having electron-withdrawing substituents. The benzoates of most alcohlos were not resolved as efficiently as the carbamates.
New Synthetic Method of [2.2]Cyclophanes via Diselena[3.3]cyclophanes
Authors: Higuchi Hiroyuki , Tani Keita , Otsubo Tetsuo , Sakata Yoshiteru , Misumi Soichi
Published: July 2006

Syntheses of cyclic diselenides through diselenolates and the following deselenation reactions by means of three ways were studied. The preparation of the cyclic diselenides in the presence of excess sodium borohydride gave thirty-eight diselenides containing diselena[3.3]cyclophanes and alicyclic diseleno compounds in high yields in addition to two triple-bridged selenacyclophanes. Photodeselenation of the diselenides in tris(dimethylamino)phosphine afforded series of [2.2]cyclophanes in much higher yields than those of the other two methods, i.e. benzyne-Stevens rearrangement/Raney nickel hydrogenolysis and pyrolytic deselenation at ca. 650 °C. The present study demonstrates that the photodeselenation method, combined with the synthesis of their precursor diselenides, is much superior to the conventional dechalcogenation methods.
Synthesis and Electrocatalytic Properties of Rare Earth Platinum or Palladium Bronzes
Authors: Machida Ken-ichi , Enyo Michio , Adachi Gin-ya , Shiokawa Jiro
Published: July 2006

Dysprosium platinum and palladium bronzes, DyM3X4 (M=Pt or Pd; X=O, S, Se, or Te) were synthesized, except for DyPt3S4, by a solid state technique. They were found to have a high electric conductivity with ρ=0.3–2.6×10−5Ω cm and among them, the oxide bronzes crystallized in NaxPt3O4 type structure. The platinum oxide bronzes in particular showed a high activity for the methanol electrooxidation as compared with ordinary platinum electrodes.
Kinetic Studies on Dehydrogenation Reaction of 5,6-Dihydro-2,4(1H,3H)-pyrimidinediones in Aqueous Solution Induced by Argon Arc Plasma or Hydrogen–Oxygen Flame
Authors: Naraoka Hiroshi , Takasaki Michiaki , Nomoto Shinya , Harada Kaoru
Published: July 2006

5,6-Dihydro-2,4(1H,3H)-pyrimidinediones underwent dehydrogenation at the 5- and 6-position producing 2,4(1H,3H)-pyrimidinediones in aqueous solution induced by argon arc plasma or flames. From consideration based on the kinetic study of this reaction, it was found that abstraction of a hydrogen atom took place preferentially at the 6-position of the dihydropyrimidinediones.
[2π+2σ] and [4π+2σ] Type Cycloaddition Reactions of Furan and Benzofurans with Benzocyclopropene
Authors: Saito Katsuhiro , Ishihara Hiraku , Kagabu Shinzo
Published: July 2006

Reactions of benzocyclopropene with furan and benzofuran afforded [2π+2σ]-type cycloaddition products, where the furans act as 2π-components and benzocyclopropene acts as a 2σ-component. A similar reaction with 1,3-diphenylisobenzofuran gave a [4π+2σ]-type cycloaddition product using the furan as a 4π-component.
Modified Solubility Parameter as an Index to Correlate the Solubility in Supercritical Fluids
Authors: Ikushima Yutaka , Goto Tomio , Arai Masahiko
Published: July 2006

The conventional solubility parameter was modified so that it could be applied to supercritical fluids. It was found that the parameters could correlate the experimental solubility data of some hydrophobic solutes in carbon dioxide, ethylene, and carbon dioxide-entrainer systems.
Preparation and Structures of Acetylene Adducts of 4,6-O-Isopropylidene- and 4-O-Acetyl-6-O-triphenylmethyl-1,5-anhydro-2-deoxy-d-erythro-hex-1-en-3-uloses
Authors: Matsui Takanao , Morooka Takashi , Nakayama Mitsuru
Published: July 2006

Cyclobutene adducts were formed stereoselectively in good yields by the irradiation of acetone solutions of 4,6-O-isopropylidene- and 4-O-acetyl-6-O-triphenylmethyl-1,5-anhydro-2-deoxy-d-erythro-hex-1-en-3-uloses, derived from d-glucal triacetate, in the presence of acetylene. The stereochemistry at the ring junction was achieved by a single-crystal X-ray analysis and a chemical correlation with the derived compounds.
Kinetic Studies on the Oxidation of Thiols by Coenzyme PQQ
Authors: Itoh Shinobu , Kato Nobuyuki , Mure Minae , Ohshiro Yoshiki
Published: July 2006

Kinetic studies on the oxidation of thiols by coenzyme PQQ are carried out under anaerobic conditions. A bell shaped pH-rate profile having a maximum rate at around pKa of the thiol is observed. The rate-determining step changes between acidic and basic sides of the profile indicating the existence of at least one intermediate in the course of the reaction.
Monolayer Formation of Dilauroylphosphatidylcholine at the Polarized Nitrobenzene–Water Interface
Authors: Kakiuchi Takashi , Yamane Masataka , Osakai Toshiyuki , Senda Mitsugi
Published: July 2006

Double layer capacitance of the polarized nitrobenzene–water interface has been measured in the presence of the adsorption of l-α-dilauroylphosphatidylcholine (DLPC). The double layer capacitance was lowered with the increase of the DLPC concentration in the negative branch of the potential range where the aqueous phase was in negative potential with respect to the nitrobenzene phase. A saturated monolayer of DLPC was formed at a concentration of DLPC above 20 μmol dm−3. The area occupied by a DLPC molecule at the saturated monolayer was 0.73 nm2 which was estimated by comparing the capacitance data with those obtained from a spread monolayer of DLPC at the interface. In the negative branch the monolayer was stable over 100 mV of the applied potential across the monolayer. The adsorption was described by the Frumkin adsorption isotherm. The interaction between the adsorbed DLPC molecule was weak, corresponding to the penetration of nitrobenzene molecules and, possibly, ions between the hydrocarbon chains of DLPC. This penetration also explains the high capacitance value of 11 μF cm−2 for the saturation monolayer. In the potential range where the aqueous phase is positive, the capacitance increased with the DLPC concentration.
Application of the SPE Method to Organic Electrochemistry. VIII. The Incorporation of an Iron Redox Couple into Pt–Nafion and Its Behavior as a Mediator
Authors: Ogumi Zempachi , Mizoe Toshiyuki , Yoshida Naoki , Takehara Zen-ichiro
Published: July 2006

Fe2+ and Fe3+ were incorporated into Pt–Nafion. The full incorporation of Fe2+ into H+-type Nafion was attained beyond 0.3 M FeSO4. The ion-exchange selectivity of Fe2+ was estimated to about 2 to H+. The incorporated ions exhibited diffusional behavior inside the composite electrode. The formal potential of the incorporated iron(III/II) redox couple was dependent on both the H2SO4 and the Fe3+ and Fe2+ concentrations. The potential shift was, however, not so large as that reported on some redox systems on polymer-coated electrodes. The incorporated redox couple was revealed to behave as a mediator in the oxidation of l-ascorbic acid.
Equilibrium Studies on the Species Formed in the Extraction of Divalent Transition Metal Ions with 8-Quinolinethiol and Its 2-Methyl Derivative
Authors: Yuchi Akio , Sugiura Kiminari , Wada Hiroko , Nakagawa Genkichi
Published: July 2006

The equilibria were studied in the extraction of divalent transition metal ions (M2+: Co2+, Ni2+, Cu2+, Zn2+, Cd2+) with 8-quinolinethiol(Hqt) and its 2-methyl derivative (Hmqt). Precipitates form in the Cd–Hqt and Cu–Hmqt systems. In other systems except the Co–Hqt, ML2(L−: qt− or mqt−) is responsible for the extraction. Effects of anions and solvents were examined in the Zn–Hqt system. The Ni(qt)2, Ni(mqt)2, and Co(mqt)2 complexes hold the capacity to form the adduct with 1,10-phenanthroline. A mixture of diamagnetic Co(III) complexes is extracted in the Co–Hqt system. The main species was assigned as mer(S)-Co(qt)3 by the 13C NMR spectrum. The structures of other complexes are also discussed.
The Thermal Decomposition of Ammonium cyclo-Hexaphosphate (NH4)6P6O18·1.5H2O and Ammonium cyclo-Tetraphosphate (NH4)4P4O12
Authors: Takenaka Atsushi , Motooka Itaru , Nariai Hiroyuki
Published: July 2006

Ammonium cyclo-hexaphosphate 1.5-hydrate (NH4)6P6O18·1.5H2O was prepared. Under conditions similar to those in the thermal analysis (TG–DTA), the hydrate was heated in an electric furnace. The atmospheres used then were streams of humid air, dried air and dry ammonia gas. The products were characterized by the X-ray diffraction method and by HPLC-flow injection analysis (HPLC-FIA). The thermal decomposition of anhydrous ammonium cyclo-tetraphosphate (NH4)4P4O12 was also investigated. From each ammonium cyclo-phosphate, very analogous ammonium polyphosphate was produced. Its formation was considered to result from the polymerization of some lower-condenced phosphate radicals, which were generated on the cleavage of the ring anions of the cyclo-phosphates. The radicals incorporated water molecules in the atmosphere, which causes less formation of the ammonium polyphosphate and exhibited a TG gain and an exothermal DTA break. The exotherm could be attributed theoretically to the incorporation in case of the cyclo-tetraphosphate. Moreover, the release of ammonia from the starting material was supposed to be a trigger for the cleavage of the ring anions.
Effect of Ru3(CO)12 and Triisopropylphosphine on the Catalytic Activity of CO Hydrogenation by Co2(CO)8
Authors: Murata Kazuhisa , Matsuda Akio , Masuda Takashi , Ishino Masaru , Tamura Mitsuhisa
Published: July 2006

A catalyst system, containing Co2(CO)8 coupled with Ru3 (CO)12 and triisopropylphosphine((i-Pr)3P), was found to be effective for the ethylene glycol formation by homogeneous hydrogenation of CO: The most active catalyst, the activity of glycol formation of which was ca. 3 times higher than that of Co2(CO)8 alone, was obtained at phosphorus: Co: Ru ratio of 2 : 1 : 1.
Interaction between Copper(I) Chloride and Active Carbon in Active Carbon-Supported Copper(I) Chloride as Solid Carbon Monoxide Adsorbent
Authors: Hirai Hidefumi , Wada Keiichiro , Komiyama Makoto
Published: July 2006

Magnetic susceptibility (−4.7×10−9 m3 kg−1) of the carbon monoxide adsorbent prepared from 10.0 g of active carbon and 1.4 g of copper(I) chloride is in paramagnetic side with respect to the value (−10.1×10−9 m3 kg−1) estimated from the susceptibilities of the components. Almost all the copper atoms are in their monovalent states, as shown by X-ray photoelectron spectroscopy. These results have indicated specific interaction between active carbon and copper(I) chloride in the adsorbent.
The Control of the Particles of Magnetite
Authors: Matsuda Keizo , Sumida Masami , Fujita Kazumi , Mitsuzawa Shunmei
Published: July 2006

Fine particles of magnetite were prepared by the hydrolysis of urea. The effects of the amount of urea on the particles were investigated. The expected particles were prepared in the range 0.8 to 2.2 μm in size by controlling the amount of urea. Fine particles of magnetite of 0.8 μm in size were prepared from a solution with R=60 (R=urea/iron(III) mol ratio).
Fluorinated Tertiary Thio- and Selenoethers from the Reaction of Sulfenyl or Selenenyl Chloride with Perfluoropropene Dimers in the Presence of Alkali Fluoride
Authors: Suzuki Hitomi , Satake Hiroshi , Uno Hidemitsu , Shimizu Hiroaki
Published: July 2006

Perfluoro(1,1-dimethylbutanide) anion generated from hexafluoropropene dimers and alkali fluorides in dry N,N-dimethylformamide, reacts with arenesulfenyl or areneselenenyl chloride to give the corresponding aryl perfluoro(1,1-dimethylbutyl) sulfides or selenides in low to good yields.
1H NMR Studies on the Motion of Cations in the Three Solid Phases of Methylammonium Perchlorate Including Cationic Self-Diffusion in Its Highest-Temperature Solid Phase
Authors: Ishida Hiroyuki , Ikeda Ryuichi , Nakamura Daiyu
Published: July 2006

The temperature dependences of the second moment of 1H NMR absorptions, the 1H spin-lattice relaxation time, T1, and the 1H spin–spin relaxation time, T2, of CH3NH3ClO4 (CH3ND3ClO4) were observed in the three solid phases existing over a wide range of temperature. In the phase I stable above 451 K, the onset of the isotropic reorientation as well as the self-diffusion of the cations with the activation energy of 36 kJ mol−1 was observed. In the phase II stable between 451 and 321 K, no remarkable change in the motional state of the cation was observed, but the dynamical orientational disorder of perchlorate anions was expected to occur. In the phase III stable below 321 K, the correlated reorientation defined as the C3 reorientation of the cation having the rigid structure, was observed at lower temperatures for two nonequivalent cations in the crystal with small activation energies of 4.4 and 2.0 kJ mol−1. The uncorrelated reorientation in which both CH3 and NH3+ groups perform C3 reorientation independently could be observed at a higher temperature with the activation energy of 6.4 kJ mol−1. Nonexponential behavior appearing in the observation of T1 below 40 K could be explained by the presence of a contribution to 1H T1 from the rotational tunneling of the cation.
The Solubility of Benzene–Hydrocarbon Binary Mixtures in Water
Authors: Sanemasa Isao , Miyazaki Yoshiko , Arakawa Seiji , Kumamaru Masaya , Deguchi Toshio
Published: July 2006

The solubility in water at 25.0°C of benzene–hydrocarbon binary mixtures has been studied for different ratios between benzene and toluene, ethylbenzene, (o-, m-, p-)xylene, propylbenzene, chlorobenzene, and cyclohexane. Aqueous solutions saturated with mixed solutes were prepared by making use of the solute vapor. The solubility of individual constituent in the binary mixture was found to change linearly with mole fraction over a whole range of the composition. This is not the case for the benzene–cyclohexane system: the solubility of each component deviates positively from the linear change of solubility with composition. The solubility of each component of benzene–1-octanol mixture in water was also measured by adding the mixture of various compositions directly to water. The positive deviation for the solubility of each component was observed. The relationship between the 1-octanol/water partition coefficient of a solute and the aqueous solubility of pure liquid solute which forms a nonideal solution in 1-octanol was discussed.
The Synthesis and Crystal and Molecular Structures of [Pentaaquabis(1-hydroxy-2-naphthoato)neodymium(III)] (1-Hydroxy-2-naphthoate) Dihydrate, [Nd{C10H6(OH)CO2}2(H2O)5][C10H6(OH)CO2]·2H2O
Authors: Ohki Yoshiyuki , Suzuki Yasuo , Shimoi Mamoru , Ouchi Akira
Published: July 2006

The title complex was synthesized, and its crystal and molecular structures were determined by the single-crystal X-ray-diffraction method. It is triclinic, with the space group of P\bar1; the cell constants are a=20.621(4), b=22.288(5), c=7.724(1) Å, α=93.30(2), β=96.78(2), γ=107.43(2)°, Z=4, and the final R value is 0.048. Although there are two kinds of crystallographically independent complexes, their structures are almost the same, with only a slight difference in the orientations of the naphthalene rings of the ligands. Both of the central metal atoms are ennea-coordinated and are in the tricapped trigonal-prism geometry: two carboxylato ligands make four-membered chelate rings, and they are also ligated five water oxygen atoms. No carboxylate ions bridge the metal atoms, but the oxygen atoms of the ligands, isolated carboxylate ions, and the crystalline water molecules are linked through hydrogen bondings along the bc-plane. The metal atoms lie on a plane parallel to (100), and the planes are separated by the layers of the naphthalene rings of the naphthoate ions.
Isomerization and Racemization of the Tris(2,2′-bipyridine N,N′-dioxide)chromium(III) Complex
Authors: Kanno Hideaki , Fujita Junnosuke
Published: July 2006

Both racemic and optically active [Cr(bpdo)3](ClO4)3·1.5H2O (bpdo=2,2′-bipyridine N,N′-dioxide) were found to crystallize in the lel2·ob(Δ(λλδ), Λ(δδλ)) isomer. The complexes isomerized spontaneously to the lel3(Δ(λλλ), Λ(δδδ)) isomer upon dissolution in water with a rapid absorption spectral change, and then racemized (Δ\ightleftarrowsΛ) slowly. The rate constant for isomerization was 5.33×10−3 s−1 at 303.2 K, and that for racemization 1.93×10−4 s−1 at the same temperature. An intramolecular conformational inversion of the bpdo chelate ring (δ\ightleftarrowsλ) and an intramolecular twist mechanism were proposed for the isomerization and the racemization of the complex, respectively. Neither isomerization nor racemization was observed for [Cr(en)(bpdo)2]3+ in aqueous solution.
Methylation of Alcohols and Phenols Adsorbed on Silica Gel with Diazomethane
Authors: Ogawa Haruo , Hagiwara Toshikazu , Chihara Teiji , Teratani Shousuke , Taya Kazuo
Published: July 2006

Alcohols and phenols adsorbed on silica gel react with diazomethane and quantitatively afford the corresponding methyl ethers. Alumina and titanium dioxide are also effective adsorbents for the reaction.
Stereoselective Formation of Allyl Ethers by Reaction of Epoxides with Organic Chlorides under Liquid-Solid Phase-Transfer Catalysis
Authors: Gu Xue-Ping , Ikeda Isao , Okahara Mitsuo
Published: July 2006

A series of trans-3-chloroallyl ethers and trans-3-thioallyl ethers were stereoselectively synthesized in one step by the reaction of 1-chloro-2,3-epoxypropane or 2,3-epoxypropyl sulfides with alkyl chlorides in the presence of solid sodium hydroxide and quaternary ammonium salt as a phase-transfer catalyst. Phase-transfer catalytic hydroxide ion-initiation followed by stereoselective isomerization of the epoxide ring through β-elimination is postulated as the important part of the reaction pathway.
The Synthesis of 1,3-Dithiolane-2-thione Derivatives
Authors: Taguchi Yoichi , Yanagiya Koshin , Shibuya Isao , Suhara Yasuo
Published: July 2006

The reaction of 2,2-dimethylthiirane with carbon disulfide in the presence of triethylamine was accelerated under high pressure to give 4,4-dimethyl-1,3-dithiolane-2-thione nearly quantitatively. The activation volume of this reaction at 40 °C was estimated to be −41 ml mol−1. The rate of the reaction was proportional to the amount of triethylamine when a limited amount of triethylamine was used. The reaction of 2-methylthiirane, 2-hexylthiirane, 1,2-epithiocyclohexane, and 2-phenylthiirane with carbon disulfide gave the corresponding 1,3-dithiolane-2-thione derivatives in good yields. 2-Chloromethylthiirane was less reactive to carbon disulfide than other thiiranes under high pressure. Tertiary amines such as N,N-dimethylethylamine, pyridine, and N-methylmorpholine were good catalysts of the reaction.
New Birch Type Reduction. Halogen or Halides-Activated Reduction of Disulfides to Thiols with Aluminium in Liquid Ammonia
Authors: Sato Ryu , Akaishi Ryouichi , Goto Takehiko , Saito Minoru
Published: July 2006

Aromatic and aliphatic disulfides were reduced to the corresponding thiols in high yields by new halogen or halides-activated Birch type reduction with aluminium in liquid ammonia.
Thermal and Photochemical Electron-Transfer Reactions of 4-Chlorobiphenyl with Lithium Diisopropylamides and Diisopropylamine
Authors: Tanaka Yoshio , Tsujimoto Kazuo , Ohashi Mamoru
Published: July 2006

A reaction of 4-chlorobiphenyl with lithium diisopropylamide in a polar solvent gave 3- and 4-(diisopropylamino)biphenyl together with biphenyl, similar to the case of photoinduced reactions of 4-chlorobiphenyl with diisopropylamine. A common electron-transfer mechanism is proposed.
Electrogenerated Chemiluminescence. 50. Electrochemistry and Electrogenerated Chemiluminescence of Micelle Solubilized Os(bpy)32+
Authors: Ouyang Jiangbo , Bard Allen J
Published: July 2006

The oxidative electrochemistry and electrogenerated chemiluminescence (ECL) of Os(bpy)32+ were studied in the presence of sodium dodecyl sulfate (SDS), Triton X-100, and cetyltrimethylammonium bromide (CTAB) in aqueous solutions. Variation of supporting electrolyte (NaCl) concentration affected the interaction between Os(bpy)32+ and the surfactants. The measurement of oxidation peak current (ipa) and ECL intensity at different NaCl concentrations suggested a strong interaction of Os(bpy)32+ with SDS. Above the critical micelle concentration (cmc) the strong hydrophobic interaction of Os(bpy)32+ and the SDS micelle core greatly suppresses both ipa and the ECL intensity. The interaction of Os(bpy)32+ with CTAB micelle is much weaker because of electrostatic effects. Triton X-100 micelles do not interact with Os(bpy)32+.
Structural Studies of Liquid 1,1,1-Trichloroethane by Means of X-Ray Diffraction
Authors: Nishikawa Keiko , Iijima Takao
Published: July 2006

The X-ray scattering intensities from liquid 1,1,1-trichloroethane (TCE) were measured at room temperature by the energy-dispersive method. By the use of the real space expansion and the reciprocal space expansion based on the local lattice structure model, structure simulation studies for TCE were carried out. A bcc model with a random orientation of the methyl group reproduces the experimental intensities well. The number of molecules in the structure region, n, was determined by a trial-and-error method, and a least-squares refinement was carried out to determine the following four parameters; the lattice constant of the bcc cell, a; the Prins parameter, D; the radius up to the continuous region, Rc; and its damping factor, lc. The refined parameters with the standard deviations in parentheses are: a=6.78 (0.11) Å, D=0.049 (0.009) Å, Rc=12.70 (0.48) Å, and lc=1.76 (1.22) Å with n=51.
The Chiral Recognition of Optically Active Poly(triphenylmethyl methacrylate) Derivatives as Stationary Phases for HPLC
Authors: Okamoto Yoshio , Yashima Eiji , Ishikura Motoshi , Hatada Koichi
Published: July 2006

Four meta-halogen- or meta-methyl-substituted optically active poly(triphenylmethyl methacrylate) [poly(TrMA)] derivatives with a one-handed helical structure were coated on macroporous silica gel and their chiral-recognition abilities as stationary phases for high-pherformance liquid chromatography were investigated with methanol or hexane–2-propanol (95:5(v/v)) as the eluent. The chiral-recognition abilities of poly(m-fluorophenyldiphenylmethyl methacrylate) and poly(m-chlorophenyldiphenylmethyl methacrylate) were slightly low compared with that of poly(TrMA) when methanol was used as the eluent. Poly[tris(m-chlorophenyl)methyl methacrylate] [poly(m-Cl3TrMA)] showed no resolving ability, although poly[tris(m-tolyl)methyl methacrylate] [poly(m-Me3TrMA)] had an effective chiral recognition ability and resolved some racemates more efficiently than poly(TrMA). When hexane–2-propanol (95/5) was used as the eluent, the optical-resolution abilities of all these chiral polymers except for poly(m-Cl3TrMA) were rather similar to that of poly(TrMA) under the same eluent system. The chiral-adsorbing sites are considered to be the chiral triarylmethyl propellers in the methanol system; carbonyl groups may also be involved in the hexane–2-propanol system. The difference in the chiral-recognition abilities of the two tri-substituted chiral polymers were ascribed to their different propeller structures and/or the different conformations of their carbonyl groups. The optical-resolution abilities of poly[TrMA-co-(m-Cl3TrMA)] and poly[TrMA-co-(m-Me3TrMA)] were also investigated. From the results, the mechanism of the separation of enantiomers on poly(TrMA) was discussed.
Kinetics of Substitution of Aqua-Ligands from cis-Diaquobis(ethylenediamine)cobalt(III) Complex by β-Alanine and Dl-Valine in Various EtOH–Water Mixtures
Authors: Chatterjee Debabrata , De G S
Published: July 2006

The kinetics of above titled reaction has been studied spectrophotometrically in various water–ethanol mixtures at different temperatures (45–60 °C). The following rate law has been established in the pH range 3.2 to 4.5.

\fracd[Co(en)2(H2O)(LH)3+]dt=\frackaKE[Co(en)2(H2O)23+]T[LH]1+KE[LH]

where LH represents the zwitterionic form of the amino acids viz. β-alanine and Dl-valine. KE is the ion-pair equilibrium constant between substrate complex ion and zwitterionic ligand the values of which increase with the increase of organic component of medium, where reverse is true for ka, the interchange rate constant from outersphere complex to innersphere product. It was observed that at higher ligand concentration a limiting rate is attained, which has been explained due to completion of ion-pair formation. Increasing effect of pH and special catalytic effect of NO3− have been observed. Activation parameters (ΔH\eweq and ΔS\eweq) have been calculated and compared with isotopic water exchange reaction and other deaquation reactions. A dissociative interchange mechanism (Id) involving ion-pair formation has been suggested.
Selective Synthesis of Ethylene by Dehydrogenative Coupling of Methane by Use of Thermal Diffusion Column
Authors: Yamaguchi Tatsuaki , Saito Chiaki
Published: July 2006

Ethylene was found to be obtained dehydrogenatively from methane in extremely high selectivities (91.5% at 9.4% conversion of methane) with the downward introduction to the modified thermal diffusion column with electrically heated tungusten wire at 1200 °C.
X-Ray Crystal Structure and Electrochemical Property of a Novel Monohydroxo-Bridged Binuclear Cobalt(II) Complex with N,N′,N″,N'″-Tetrakis(2-aminoethyl)-1,4,8,11-tetraazacyclotetradecane
Authors: Mikuriya Masahiro , Kida Sigeo , Kohzuma Takamitsu , Murase Ichiro
Published: July 2006

The crystal structure of a binuclear cobalt(II) complex of N,N′,N″,N'″-tetrakis(2-aminoethyl)-1,4,8,11-tetraazacyclotetradecane (taec), [Co2(taec)(OH)](ClO4)3, was determined by the single-crystal X-ray diffraction method. The two cobalt ions are bridged by a single hydroxide ion in the cavity of taec. The cyclic voltammogram showed an irreversible profile with two anodic peaks at ca. 1.4 and 1.8 V vs. SCE.
Stereospecific Synthesis of 3-Oxo-α-bourbonene and the Cisoid Isomer for Structural Determination of the Toxic Component of Lansium domesticum
Authors: Uyehara Tadao , Suzuki Ichiro , Yamamoto Yoshinori
Published: July 2006

The cis-cisoid-cis isomer of 3-oxo-α-bourbonene, (1), the original structure proposed for the toxic principle of Lansium domesticum, has been prepared from (−)-mintsulfide. Neither spectral data of 1 nor of 3-oxo-α-bourbonene itself, derived from β-bourbonene, are not identical with those of the toxic componet.
A Systematic Investigation of the Effects of Axial Ligands and Peripheral Substituents on the Electronic Structures of Zinc(II) Tetraphenylporphyrin π-Cation Radicals: Electrochemical EPR and Spectroscopic Observation
Authors: Ichimori Kohji , Ohya-Nishiguchi Hiroaki , Hirota Noboru
Published: July 2006

A detailed study of the effect of axial ligand and peripheral substituent on the π-system of zinc(II) tetraphenylporphyrin π-cation radical has been made using an electrochemical EPR technique. It is confirmed from the EPR spectra that most of the anions and bases examined coordinate the radicals axially. The spin density on the nitrogen nuclei in the radicals increases with the polarizability of the axial ligand estimated from the optical spectra of the parent neutral complexes. For the fourteen complexes with different substituents on the phenyl groups examined here, there is a linear correlation between the Hammett substituent constant and the spin density. It is also shown that the para position of the phenyl group carries the spin density comparable to that of the ortho position, which indicates considerable conjugation between the porphyrin ring and the phenyl groups. In most cases, there exist two kinds of radical species which give rise to broad and sharp EPR spectra at low temperature. It is suggested that the difference in the motional states of the phenyl groups in the radicals is responsible for the different EPR spectra.
Effect of the N-Methylation of Dodecylammonium Chloride on the Adsorption from Its Micellar Solution
Authors: Aratono Makoto , Okamoto Toru , Ikeda Norihiro , Motomura Kinsi
Published: July 2006

The surface tension of the aqueous solution of dodecylmethylammonium chloride (DMAC) and dodecyldimethylammonium chloride (DDAC) was measured as a function of temperature under atmospheric pressure at concentrations below and above the critical micelle concentration (cmc). The entropy and energy of adsorption from the monomeric state in the aqueous solution and the micellar state were evaluated by applying the thermodynamic equations of adsorption to the surface tension values. The thermodynamic quantities were compared with those of the aqueous solutions of dodecylammonium chloride (DAC) and dodecyltrimethylam-monium chloride (DTAC). It was found that the successive N-methylation of DAC has a considerable effect on the adsorbed film with changes in its surface density, entropy, and energy brought about by changes in the geometry and the hydrophilicity of the polar head group.
The Solubility of Peptide Intermediates in Organic Solvents. Solubilizing Potential of Hexafluoro-2-propanol
Authors: Narita Mitsuaki , Honda Shinya , Umeyama Hiroshi , Obana Satoshi
Published: July 2006

The solubility of peptides to be insoluble in EtOH, MeOH, DMF, DMA, NMP, DMSO, and HMPA was examined in HFIP, sulfolane, TMP, PC, and a mixture of 5–10% HFIP–CH2Cl2 (v/v). HFIP has the highest solubilizing potential, followed by HMPA and DMSO, while the solubilizing potential of sulfolane, TMP, and PC is lower than that of HMPA, DMSO, DMF, and NMP and is close to that of MeOH and EtOH. The solubility of the peptides in the mixture of HFIP–CH2Cl2 marvelously is as high as that in HFIP alone. The solvent-titration study in CH2Cl2–polar solvents clearly indicated that the solubility of peptides having a β-sheet structure in organic solvents was independent of the polarity of the solvents but was strongly dependent on their hydrogen donating and accepting ability. The conformation of the peptides in the mixture of HFIP–CH2Cl2 and in HFIP alone was examined using the IR and CD spectroscopies, respectively.
Synthesis and Acid-Catalyzed Ring Opening of 1-Alkenyl Cyclopropyl Ketones
Authors: Tsuge Otohiko , Kanemasa Shuji , Otsuka Tatsuya , Suzuki Toshiro
Published: July 2006

1-Alkenyl cyclopropyl ketones, when activated by cation-stabilizing substituents at the ring carbon or at the terminal carbon of the enone moiety, undergo polyphosphoric acid-catalyzed ring enlargement producing cyclopentanone or cyclohexenone derivatives. Similar acid-catalyzed ring opening of 1-alkenyl 2-phenoxycyclopropyl ketones offers a convenient and effective synthesis of 4-oxo-5-alkenals and their dioxolaneprotected derivatives.
An Ab Initio Molecular Orbital Study of Pyridyl Radicals
Authors: Kikuchi Osamu , Hondo Yuji , Morihashi Kenji , Nakayama Mitsunobu
Published: July 2006

Open-shell RHF and UHF ab initio calculations were carried out for 2-, 3-, and 4-pyridyl radicals in order to determine their molecular structures and relative energies. The minimal STO-3G basis set was used for the structure optimization, while the 4-31G basis set was used for the energy evaluation. The 2-pyridyl radical has the lowest energy, although the energy differences among these three isomers were very small. The possibility of a Π-ground state in pyridyl radicals was rejected.
Kinetics of the Denaturation of Ovalbumin and S-Ovalbumin by Alcohols
Authors: Murakami Kiyofumi
Published: July 2006

The kinetics of denaturation of ovalbumin and S-ovalbumin by butyl alcohol isomers (butyl alcohol, isobutyl alcohol, s-butyl alcohol, and t-butyl alcohol) have been studied. The reactions were characterized as first order with respect to the protein and 11th order for the alcohols, irrespective of the kind of protein or alcohol. The rate constant was, however, significantly reduced by the branching of the alcohol structure and by the conversion of native ovalbumin to S-ovalbumin. The measurements were also performed on ovalbumin and S-ovalbumin whose SH groups were blocked from SH\ightleftharpoonsS–S exchange reactions by modification with iodoacetamides. By the conversion to S-ovalbumin, the modified protein also exhibited a considerable resistivity against denaturation, suggesting that SH\ightleftharpoonsS–S exchange reactions play no essential role in the formation of S-ovalbumin. On the basis of these results as well as determined activation parameters, the mechanism of the denaturation is discussed in the light of a combination of the hydrophobic interactions, between hydrophobic residues of the proteins and the alcohol molecules, and the fluctuations of the protein structures.
Pulse Radiolysis Studies of Solvent Radical Cations in Liquid 1,2-Dichloroethane
Authors: Sumiyoshi Takashi , Sugita Naoki , Watanabe Kazuyuki , Katayama Meiseki
Published: July 2006

Transient absorption spectra with maxima at 270 and 550 nm were observed in liquid pure 1,2-dichloroethane by means of ps and ns pulse radiolysis. The broad absorption band with a maximum around 550 nm decayed according to a first-order reaction with t1⁄2=0.2 ns in ps pulse radiolysis and t1⁄2=200 ns in ns pulse radiolysis. These short lived species were attributed to solvent cations on the basis of scavenger experiments. The slowly decaying species with t1⁄2=1.2 μs which absorbs around 400 nm superimposed on the 550 nm band, was tentatively assigned to carbocations. The 270 nm band formed during and after the electron pulse decayed over several microseconds by second-order kinetics. Those radicals which were produced by the dissociative electron attachment to the solvent and by the reaction of cations were responsible for this UV band.
The Heat of Immersion in Water and the Nature of the Surface Hydroxyl Group of Maghemite and Hematite
Authors: Watanabe Haruo , Seto Jun’etsu
Published: July 2006

The heats of immersion in water of maghemite (γ-Fe2O3) were measured in comparison to those of hematite (α-Fe2O3) prepared from the same maghemite by crystal transformation with heat treatment, and outgassing up to 200 °C. The heats of immersion and the heat of hydration of maghemite were lower than those of hematite throughout the measurement conditions. These differences were concluded to be due to the differences in bulk crystal structure, especially the density of the crystal. That is, the heat of hydration at the stage of physisorption depends on the surface hydroxyl group density, corresponding to the bulk crystal density. Also the surface hydroxyl groups are strongly affected by the polarization of the bonds in the bulk, this results in the difference of the heat of hydration at the stage of chemisorption (formation of the hydroxyl groups) and the acidity of the hydroxyl groups. This view is confirmed on the polymorphs of other metal oxides.
Novel Racemization of Atropisomeric Flavins and 5-Deazaflavins via Adduct Formation
Authors: Shinkai Seiji , Nakao Hideki , Yamaguchi Toshiro , Manabe Osamu
Published: July 2006

The molecular structures of covalent adducts derived from flavins and 5-deazaflavins are discussed on the basis of racemization of atropisomeric flavins and 5-deazaflavins. The 5-adducts with SO32− and CN− underwent facile racemization, indicating that the molecular structure changes from the “tense” planar state to the “relaxed” bent state. On the other hand, the 4a-adduct prepared by the photo-alkylation method did not racemize at room temperature. This indicates that the structure of the 4a-adduct is different from the bent 5-adduct. These results provide an information useful to discuss the reduced state of flavoproteins.
Topological Index and Thermodynamic Properties. IV. Size Dependency of the Structure-Activity Correlation of Alkanes
Authors: Gao Ying-duo , Hosoya Haruo
Published: July 2006

Correlation coefficients between twelve thermodynamic properties (ΔS, ΔHf, ΔGf, bp, d, nD, Rm, Vm, pc, Tc, Vc, dc) of 624 isomers of nonane through dodecane and five different topological indices (Z, p3, w, p2, A3) were calculated, where the new index A3 is proposed to be defined as the half sum of the off-diagonal elements of the cube of the adjacency matrix A. These properties can be classified into several types, according to the behavior of the two correlation coefficients, ρ(Z) and ρ(p3), against the change of the size of molecules. ΔS and bp depend largely on Z, while d and nD on p3, irrespective of the size change of molecules. On the other hand, ΔHf of smaller alkanes is largely dependent on Z, but for larger alkanes it turns out to be a p3-dependent property. Various interesting behaviors of the structure-activity relationships including the “pentane effect” were observed and discussed.