bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereoselective syn-Reduction of (R)-4-Acyl-2,2-dimethyl-1,3-dioxolanes with Metal Hydride Reagents
Authors: Chikashita Hidenori , Nikaya Toshiki , Uemura Hiromitsu , Itoh Kazuyoshi 
Published: July 2006

Abstract
Lithium tri-s-butylborohydride and lithium aluminum hydride were found to be efficient reducing agents for the stereoselective preparation of syn-glycerol derivatives from (R)-4-acyl-2,2-dimethyl-1,3-dioxolanes. The scope and limitation of the stereoselective l-Selectride reduction of (R)-4-acyl-2,2-dimethyl-1,3-dioxolanes were also described.
A Mechanistic Study of a Gas-Phase Ion/Molecule Reaction between CH2NH2+ and CH4
Authors: Okada Satoshi , Abe Yasuo , Taniguchi Setsuo , Yamabe Shinichi , Minato Tsutomu 
Published: July 2006

Abstract
A gas-phase ion/molecule reaction starting from (CH4+ and N2O)/(CH4 and N2O+) is studied using a pulsed-discharge high-pressure mass spectrometer and the ab initio MO calculation. Two dominant ions, C2H6N+ and C3H8N+, are recognized; they are formed by the methylation of CH4N+. The C2H6N+ is formed via the following two reactions:
CH2NH2+(or CH3NH+)+CH4 → (CH3)2NH2+ (5)
(CH3)2NH2+ → CH3NHCH2++H2 (7)
The methylation is composed of the heterolytic CH3+–H− addition to the C=N bond of CH4N+ and the subsequent H2 elimination. The growth of the ion by the methylation is largely exothermic, while the H2 elimination has a large energy barrier on the potential energy surface.
The Addition Effects of Methyl Halides on Ethane Ignition Behind Reflected Shock Waves
Authors: Takahashi Kazuo , Inomata Tadaaki , Moriwaki Takao , Okazaki Satiko 
Published: July 2006

Abstract
Ignition delay times were measured in C2H6–O2–CH3X(X:Cl, Br or I) mixtures highly diluted with argon behind reflected shock waves. The measurements covered a temperature range of 1200–1900 K and the pressure range of 1.4–2.9 atm. The times were longer than those without CH3X, indicating that CH3X inhibits ethane ignition. This was contrary to the previous results which showed that CH3X promoted methane ignition. To clarify the addition effects of CH3X from the viewpoint of the reaction mechanism, computational analyses were performed in C2H6–O2–CH3Br and CH4–O2–CH3Br mixtures. The analytical results showed that different chain cycles for Br-containing species were formed in the two mixtures. The opposite effects of CH3Br on ethane and methane ignitions could be interpreted in terms of these different cycles.
Dynamics of Exciplex Formation in Cholesteric Liquid Crystals Containing Carbazolyl and Terephthaloyl Group
Authors: Kawaguchi Koji , Sisido Masahiko , Imanishi Yukio , Kiguchi Masashi , Taniguchi Yoshio 
Published: July 2006

Abstract
Dynamics of exciplex formation was studied on cholesteric liquid crystals consisting of cholesteryl 3-(9-ethyl-3-carbazolyl)propanoate (3Cz-2), cholesteryl 5-phenylpentanoate (Ph-4), and cholesteryl methyl terephthalate (CMT) with different amounts of CMT. Transient fluorescence spectrum and the analysis of fluorescence rise and decay curves of the exciplex emission indicated that two types of exciplex are present at low temperatures. Rate constants of exciplex formation were obtained at different temperatures in the cholesteric and isotropic phases. The activation energy for the rate constant was nearly zero in the cholesteric phase, but it was positive (3–6 kcal mol−1) in the isotropic phase. The difference was interpreted in terms of different mechanisms of exciplex formation in the two phases.
Electronic Spectra of Square-Planar Bis(biuretato)cobaltate(III)-Type Complexes
Authors: Komorita Takashi , Fujita Masanori B , Kanamori Kan , Hayashi Sawako , Shimura Yoichi 
Published: July 2006

Abstract
Several square-planar cobalt(III) complexes of bis(biuretato)-type were synthesized with new quadridentate ligands, alkylenebis(biuret)’s, where alkylene bridging group is (R,S)- or (R)-propylene, 1,1-dimethylethylene, cis-1,2-cyclohexylene, or tetramethylethylene. Faraday parameters for possible CT transitions in the complexes were expressed as functions of MO coefficients and energies. From the examination of the magnetic circular dichroism, the intense absorption band observed at ca. 20×103 cm−1 was assigned to ligand-to-metal charge-transfer transitions of ligand π(au of D2h) to metal dyz and dzx′, and the ground state was inferred to be one close to D4h symmetry. The band assignment was also consistent with the resonance Raman spectrum of potassium bis(biuretato)cobaltate(III). Absorption spectra of the complexes occasionally lost intensity with decrease of temperature. Origin of the thermochromism, which was found to be reversible, was also discussed.
The Polymerization of Toluene and Its Analogs Catalyzed by a Copper(I) Chloride–Aluminum Chloride–Oxygen System
Authors: Toshima Naoki , Kanaka Keiichi , Ishiyama Naoko , Hirai Hidefumi 
Published: July 2006

Abstract
The polymerization of aromatic compounds other than benzene (such as toluene, xylene, ethylbenzene, mesitylene, and biphenyl) was performed by using a copper(I) chloride–aluminum chloride–oxygen system which caused benzene to polymerize. Excess aluminum chloride, with respect to copper(I) chloride, was required for these compounds to polymerize, as was also true for benzene. For example, the treatment of toluene with aluminum chloride and copper(I) chloride (15:3:1 in molar ratio) under 1 atm of oxygen at 50°C for 24 h gave toluene polymer in 204% yield based on copper(I) chloride. This fact suggests that copper(I) chloride also worked as a catalyst in the case of the polymerization of toluene. The toluene polymer was obtained as both solid and liquid products, both of which were soluble in various organic solvents. The solid product has a complicated, crosslinked and “quinonoid-like” structure. On the other hand, the liquid product has a structure that is nearly identical with that of methylated poly(1,4-phenylene). Other alkylbenzenes gave the only liquid polymerization products, except for o-xylene which gave a small amount of solid products. The polymerization of biphenyl gave a low-molecular-weight poly(1,4-phenylene).
Substituent Effect on the Enantiomer-Differentiating Reaction of Lithiomethyl p-Tolyl Sulfoxide with Meta- or Para-Substituted (R)-(−)-Menthyl Benzoates
Authors: Kunieda Norio , Nakanishi Takeshi , Kinoshita Masayoshi 
Published: July 2006

Abstract
Treatment of (R)-(−)-menthyl benzoates, which have a variety of meta- or para-substituents, with 2 equivalents of racemic lithiomethyl p-tolyl sulfoxide displays the feature of an enantiomer-differentiating reaction, affording the corresponding optically active β-keto sulfoxides. The degree and the direction of enantioselectivity were affected by the nature of the substituent on benzene ring. The electron-releasing substituents trend to increase the %e.e. value. The reversal in the configuration with the variation in the substituent which has a high electron-withdrawing p-CN group was also observed. The R⁄S values thus obtained gave a good correlation with Hammett’s a values (r=0.975), affording a negative straight line. Based on these observations, a plausible stereochemical course of this reaction has been discussed.
Structure and Optical Properties of a Thermochromic Schiff Base. Low-Temperature Structural Studies of the N,N′-Disalicylidene-p-phenylenediamine and N,N′-Disalicylidene-1,6-pyrenediamine Crystals
Authors: Inabe Tamotsu , Hoshino Naomi , Mitani Tadaoki , Maruyama Yusei 
Published: July 2006

Abstract
The crystal structure of N,N′-disalicylidene-p-phenylenediamine (BSP) has been determined at 108 K. This compound shows a thermochromic-type behavior in the crystalline state; this chromism has been interpreted in terms of an intramolecular proton transfer from the hydroxyl oxygen to the imine nitrogen through the O–H···N hydrogen bond. In comparison with the room-temperature structure, no significant differences in the molecular structure and the molecular packing in the lattice have been observed. The room-temperature and low-termperature structures of another N,N′-salicylideneaniline derivative, N,N′-disalicylidene-1,6-pyrenediamine (DSPY), have also been determined. In contrast to BSP, the absence of a thermal proton-transfer process in DSPY is suggested by optical measurements. Comparative studies of these two compounds indicate that a conjugation system which is not included in a π-electron configurational change by the proton transfer must be coplanar with the hydrogen-bonded chelate ring for the thermal proton transfer.
Crystal Structures and Electrical Properties of Tetrakis(methylseleno)tetrathiafulvalene (TSeC1-TTF) and Two Phases of (TSeC1-TTF)I3
Authors: Wang Ping , Inabe Tamotsu , Nakano Chikako , Maruyama Yusei , Inokuchi Hiroo , Iwasawa Naoko , Saito Gunzi 
Published: July 2006

Abstract
The crystal structure and the electrical property of TSeC1-TTF as well as those of the new complex (TSeC1-TTF)I3 with two kinds of phases are reported. The crystal structure of TSeC1-TTF was determined to be monoclinic, space group P21⁄a, a=7.728(1), b=20.952(4), c=5.315(1) Å, and β=90.57(2)° having a unit cell volume of 860.6(3) Å3. By an electrochemical method and a diffusion method, TSeC1-TTF gave two forms of single crystals of (TSeC1-TTF)I3. The crystal data of one form; monoclinic, space group P2⁄a, a=24.359(1), b=11.831(3), c=7.842(6) Å, β=96.71(4), V=2244(1) Å3 and those of the other; monoclinic, space group P2⁄a, a=23.174(5), b=11.727(3), c=8.960(5) Å, β=110.54(2)°, a=2280(1) Å3. The former complex has lower resistivity, 4.1×104Ω cm, compared with the latter one 1.1×108Ω cm. The dimerization is more noticeable in the latter complex than in the former one.
The Ab Initio Modeling of Hammett-Type Correlations. The Separation of Inductive Effects from Mesomeric Effects in Aromatic Systems
Authors: Niwa Jun 
Published: July 2006

Abstract
Substituent effects have been modeled using both substituted hydrogens and substituted benzenes perturbed with point charges in order to separate the inductive (field) effect from the mesomeric effect with the use of ab initio techniques. Several pure dipole ‘substituents’ have been introduced to derive the scale of inductive effects common to both aliphatic and aromatic systems. In the above systems the interaction energies have been estimated by dividing into electrostatic interaction and polarization. Calculations with the use of 4-31G basis set show satisfactory correlations with the experimentally determined substituent constants. The propriety of the present approach has also been examined for the gas-phase acidities of phenols.
Chelate Stability Constants of N-(o-Hydroxybenzyl)iminodiacetic Acid (HBIDA) with Yttrium and Lanthanoid Ions
Authors: Yoshida Isao , Sagara Fumio , Ueno Keihei 
Published: July 2006

Abstract
Chelate stability constants of N-(o-hydroxybenzyl)iminodiacetic acid with yttrium and some lanthanoid ions (M3+) were determined by the potentiometric method at 25 °C and at an ionic strength of 0.1 with potassium nitrate. The computation of the titration data indicated that four kinds of complexes, ML, ML23−, M(HL)+, and M(HL)2− (except for thulium and lutetium) were formed on each metal ion and the values of the stability constants increased with the increase of atomic number of the element. The values found for the stability constants of yttrium complexes are between those for gadolinium and terbium ions.
Thermotropic Behavior of Proteins and Acylated Proteins in Monolayers
Authors: Mita Tomoyoshi 
Published: July 2006

Abstract
In order to obtain information concerning the effect of proteins on the thermotropic properties of biological membranes, the temperature-dependences of monolayers of different proteins and some acyl derivatives of bovine serum albumin (BSA) have been investigated. The hydrophobic proteins such as hemoglobin, β-lactoglobulin, and β-casein formed dilute monolayers, whereas the hydrophilic proteins such as cytochrome C and lysozyme formed concentrated monolayers. BSA showed an intermediate isotherm between those of dilute and concentrated films. The monolayers of BSA, cytochrome C, and lysozyme were gradually expanded with increasing temperatures. However, the temperature-dependences of the monolayers of hemoglobin, β-lactoglobulin, β-casein, and acyl derivatives were significantly different from those of the monolayers of hydrophilic proteins. In detail, the monolayers of hemoglobin and β-lactoglobulin formed the most compact structures around 20 °C and 30 °C, respectively, while the monolayers of β-casein formed the most expanded structure around 30 °C. In addition, the monolayers of acetyl and propionyl derivatives formed the most compact structures around 30 °C. These results suggest that the hydrophobicity of protein is an important factor relating to thermal stability of proteins in monolayers.
The Synthesis and Oxidation of Mixed Cobalt(III) Complexes with Dimethyldithiocarbamato and Diamine Ligands, and the Crystal Structure of (+)500CD-Dimethyldithiocarbamatobis(ethylenediamine)cobalt(III) Bis[μ-(R,R)-tartrato]dianxtimonate(III) Pentahydrate
Authors: Kita Masakazu , Yamanari Kazuaki , Shimura Yoichi 
Published: July 2006

Abstract
Dithiocarbamato complexes, [Co(dtc)3−n(diamine)n]n+ (n=1 and 2 and dtc=dimethyldithiocarbamate) were newly prepared and characterized by means of their absorption, CD, and MCD spectra. (+)500CD-[Co(dtc)(en)2][Sb2(R,R-C4H2O6)2]·5H2O crystallized in the monoclinic space group of P21 with a=14.630(3), b=9.300(1), c=12.023(5) Å, β=110.78(3)°, V=1529.4(8) Å3, and Z=2. The refinement of 3346 reflections (Mo Kα radiation) led to R=0.073. The dtc complex had a Λ configuration. The Co–N bond trans to the dtc sulfur atom was longer by 0.026 A than the cis one. A novel oxidation derivative, [Co{(dimethylamino)thioxomethanesulfinato-O,S}(en)2]2+, was prepared and characterized by means of its XPS spectrum.
The Esterification of Carboxylic Acid with Alcohol over Hydrous Zirconium Oxide
Authors: Takahashi Kyoko , Shibagaki Makoto , Matsushita Hajime 
Published: July 2006

Abstract
The esterification of carboxylic acids with alcohols proceeded efficiently with hydrous zirconium oxide to give the corresponding esters in the vapor phase, in the liquid phase, and in an autoclave. The steric hindrance of carboxylic acids and alcohols affected the esterification by lowering the reactivity. With a rise in the reaction temperature, the conversion of the carboxylic acid increased. The dehydration of alcohols was prevented by using hydrous zirconium oxide in spite of the high reaction temperature. The reaction rate is first-order with respect to the concentration of the catalyst and an alcohol and is inversely proportional to that of the carboxylic acid. Transesterification also proceeded efficiently.
A Resonance Raman Study of Polymeric Thiolato Cobalt(III) Complexes: Possible Bridging Modes
Authors: Kanamori Kan , Ino Sonomi , Mizuno Yumiko , Kanesaka Isao , Kawai Kiyoyasu , Hidaka Jinsai 
Published: July 2006

Abstract
The resonance Raman spectra of polymeric CoIII {SCH2CH(NH2)COOH-S}3 and Na3CoIII (SCH2COO-S)3 complexes were investigated. The complexes gave two totally symmetric Co–S stretchings, indicating the presence of two different Co–S–Co bridging modes in the complexes. Possible bridging modes are discussed in relation to their structures.
Adsorption-Assisted Desorption and Cross Desorption of CO and H2 on Nickel Polycrystalline Surfaces
Authors: Yamada Taro , Zhai Runsheng , Iwasawa Yasuhiro , Tamaru Kenzi 
Published: July 2006

Abstract
The rates of adsorption and desorption during co-adsorption process of CO and H2 on the Ni polycrystalline surface were measured. The desorption rate of CO(a) was enhanced by the presence of CO(g) or H2(g) in the gas phase. The desorption rate of adsorbed hydrogen was accelerated by CO(g) but not by H2(g).
A Flow-Through Detector Based on the Photoelectrochemical Reaction of an Anthraquinone-2,6-disulfonate Dianion/Cationic Perfluoro Polymer Complex
Authors: Egashira Naoyoshi , Fujisawa Toshirou , Ohga Kazuya 
Published: July 2006

Abstract
A glassy carbon electrode modified with an anthraquinone-2,6-disulfonate dianion/cationic perfluoro polymer complex was used as the working electrode of a flow-through detector based on a photoelectrochemical reaction. Several α-amino acids gave anodic photocurrents. The photocurrent-peak area of proline increased linearly with the concentration in the range of 0.5–10 mmol dm−3 and the detection limit (S/N=2) was 5×10−5 mol dm−3.
Photoreaction of (E)-1-Mesityl-2-(2,4,6-tri-t-butylphenyl)diphosphene
Authors: Yoshifuji Masaaki , Sato Takahiro , Inamoto Naoki 
Published: July 2006

Abstract
Photoirradiation of (E)-1-mesityl-2-(2,4,6-tri-t-butylphenyl)diphosphene gave 1,2-bis(2,4,6-tri-t-butylphenyl)diphosphene via a cyclotetraphosphane.
Convenient Syntheses of Condensed Phenalenones. The Synthesis of Indeno[1,2-a]phenalene-6,8-dione and Its Dication
Authors: Kuroda Shigeyasu , Hirooka Syuzi , Tanaka Eishi , Fukuyama Yuriko , Tsuchida Tomohiko , Nakagawa Koichi 
Published: July 2006

Abstract
Convenient and general syntheses of condensed phenalenones with various ring systems fused at the 7 and 8-positions are described together with the synthesis of indeno[1,2-a]phenalene-6,8-dione (quinone) and the formation of its di-cationic species in strong acidic media.
Insolubilizing Studies of Water-Soluble Poly(Lys Tyr) by Tyrosinase
Authors: Nagai Akira , Yamamoto Hiroyuki 
Published: July 2006

Abstract
Insolubilization of water-soluble synthetic poly(Lys Tyr) was examined using tyrosinase in water and simulated seawater systems. Tyrosinase oxidized tyrosine aromatic nuclei, causing intermolecular crosslinking reactions. The salinity, system pH and α-chymotrypsin are considered to play roles in the insolubilizing reaction.
Nucleophilic Displacement of Bis(perfluoroalkanoyl) Peroxides with Perfluoroalkanoate
Authors: Yoshida Masato , Sasage Shyuichi , Kamigata Nobumasa , Sawada Hideo , Nakayama Masaharu 
Published: July 2006

Abstract
Bis(perfluoroalkanoyl) peroxide ((RFCO2)2) suffered a nucleophilic displacement with perfluoroalkanoate (RF′CO2−) to give new mixed peroxide (RF(CO)OO(CO)RF′). When thiophene was reacted with bis(perfluoroalkanoyl) peroxide in the presence of pyridinium perfluoroalkanoate, not only the perfluoroalkyl group (RF) of the peroxide, but also perfluoroalkyl group (RF′) of perfluoroalkanoate, was introduced into thiophene.
Nitrogen-15 NMR Chemical Shifts in Metal–Ammine Complexes. II. Cobalt(III) Ammine and Amine Complexes
Authors: Nakashima Yoshiaki , Muto Masayuki , Kawano Keiichi , Kyogoku Yoshimasa , Yoshikawa Yuzo 
Published: July 2006

Abstract
15N nuclear magnetic resonance spectra were measured for [CoX(15NH3]n+ (X=CN−, 15NH3, H2O, and Br−) and cis-[CoX2(en-15N,15N)2]n+ (X2=(CN−)2, (NO2−)2, en-15N,15N, ox2−, and (H2O)2; en-15N,15N and ox2− represent the 15N-enriched ethylenediamine and oxalate ion, respectively). Two sharp signals of 15N NMR were observed for [CoX(15NH3)5]n+ except for the cases of X=15NH3 and NO2−. The signals of 15N NMR in cis-[CoX2(en-15N,15N)2]n+, were assigned on the basis of the selectively proton irradiated spectra at frequencies which had been already assigned to each amino proton. The chemical shifts of 15N NMR are correlated to the Co–N bond strength; it is expected that the stronger is the Co–N bond, the greater is the shift of the 15N NMR signal to a higher field. When we express [CoX(15NH3)5]n+ and cis-[CoX2(en-15N,15N)2]n+ as [CoXN5]n+ and cis-[CoX2N4]n+, the effect on the 15N NMR chemical shifts by the substituent X is roughly additive.
A Complex Generated in a Cationic Surfactant-Aromatic Additive System
Authors: Hirata Hirotaka , Kanda Yumi , Sakaiguchi Yuko 
Published: July 2006

Abstract
Aqueous binary solutions of hexadecyltrimethylammonium bromide (HTAB) and o-iodophenol (OIPh) exhibit remarkable viscoelasticity. From the centrifuged sediment of such a solution a crystalline product was isolated on long standing. Elementary analysis of the crystals for C, H, and N gave an estimated composition consistent with a one-to-one molar ratio of the two substances. Comparisons with DSC and IR measurements on the crystal and equimolar mechanical mixtures suggested that a crystalline complex was formed characterized by low thermal stability.
Solution Properties of Sodium Perfluoroalkanoates. Heats of Solution, Viscosity B Coefficients, and Surface Tensions
Authors: Tamaki Kunio , Ohara Yoko , Watanabe Sumiko 
Published: July 2006

Abstract
The heats of solution, the viscosity B coefficients, and the surface activities of sodium perfluoroalkanoates, F(CF2)nCOONa, n=1–4, 6, 7), in water were measured. The changes in the heat capacity for dissolution in water, ΔCp∞, calculated from the heats of solution at 15, 25, and 35 °C, were positive for the salts, and the ΔCp∞ values increased with an increase in n. The increment in the ΔCp∞ values per CF2 group was 93 J K−1 mol−1. The viscosity B coefficients increased with the chain length at a definite temperature, and the increment in the viscosity B coefficients per CF2 group was 0.119 dm3 mol−1 at 25 °C. Further, the viscosity B coefficients for all the salts decreased with the increase in the temperature between 15 and 35 °C. Traube factors, as obtained from the surface tensions, were found to be 3.0 for the homologs from C2 salt to C7 salt. The results are discussed in comparison with those of sodium alkanoates, H(CH2)nCOONa.
Effects of Temperature on the Solvent Extraction of Zinc and Cadmium Complexes with 8-Quinolinol and 2-Methyl-8-quinolinol into 1,1,2,2-Tetrachloroethane, 1-Octanol, and p-Xylene
Authors: Nakayama Eiichiro , Sohrin Yoshiki , Isshiki Kenji , Karatani Hajime , Yamada Etsu 
Published: July 2006

Abstract
The effects of temperature on the extraction of zinc(II) and cadmium(II) complexes with 8-quinolinol (HQ) and 2-methyl-8-quinolinol (HR) into three different types of organic solvents whose boiling points are relatively high were studied. 1) In the case of 1,1,2,2-tetrachloroethane (TCE), the extraction equilibrium can be written as follows (except for that of zinc with 2-methyl-8-quinolinol):
2M2++6HQ(o)+X−\ightleftarrowsM2Q3(HQ)3+(o)+X−(o)+3H+,
where X− refers to various inorganic anions. An ion-pair of the binuclear complex (complex ion pair) dissociates into a complex cation and an inorganic anion in the organic phase. The distribution ratios decrease remarkably with an increase in temperature. 2) In the 1-octanol (S) extraction system, zinc and cadmium are extracted as solvent-adducts, such as MQ2·S2. The distribution ratios are almost constant with a change in temperature. 3) In the p-xylene extraction system, a hydrated metal complex, MQ2·2H22H2O, may precipitate and be deposited at the interface of both phases, except for the extraction of zinc with 2-methyl-8-quinolinol. 4) The zinc complexes of 2-methyl-8-quinolinol are extracted into TCE and p-xylene as anhydrous complexes, such as MR2. The distribution ratios increase with an increase in temperature. Moreover, zinc can be separated from cadmium at high temperatures using 2-methyl-8-quinolinol and TCE.
Solvent Effect on the Liquid–Liquid Partition of 21H,23H-Porphine between Various Organic Solvents and Acidic Aqueous Solutions
Authors: Wakui Yoshito , Imura Hisanori , Suzuki Nobuo 
Published: July 2006

Abstract
The liquid–liquid partition equilibrium of 21H,23H-porphine has been investigated at 25 °C. Organic phases were heptane, dodecane, carbon tetrachloride, benzene, toluene, chloroform, dichloromethane, and 1-octanol. The acidic aqueous phases were 5×10−2–5×10−1 M hydrochloric acid. Porphine is present in such acidic solutions as a diprotonated form and no dimerization was found in any of the systems. The organic solvent effect on the partition coefficient of porphine is discussed with the aid of regular solution theory, and the solubility parameter of porphine is estimated as 10.7±0.6 cal1⁄2 cm−3⁄2.