bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Crystal and Molecular Structures of trans-Dichlorobis(dimethyl-neomenthylphosphine)palladium(II) and trans-Dichloro-bis(dimethylmenthylphosphine)palladium(II), Asymmetric Hydrosilylation Catalysts of Olefin
Authors: Kan Kojiro , Miki Kunio , Kai Yasushi , Yasuoka Noritake , Kasai Nobutami 
Published: July 2006

Abstract
The molecular structures of [PdCl2{(Me2neoMen)P}2] and [PdCl2{(Me2Men)P}2], asymmetric hydrosilylation catalysts of olefin, were determined by means of X-ray diffraction. Both complexes form yellow prismatic crystals. The former belongs to the monoclinic system: a=13.512(5), b=13.082(1), c=8.472(1) Å, and β=97.00(2)°, space group P21 with Z=2; the latter belongs to the tetragonal system: a=9.662(1) and c=32.459(2) Å, space group P43212 with Z=4. Both structures were determined by the heavy atom method and have been refined anisotropically by a least-squares procedure (R=0.0697 for 2606 non-zero reflections for the former and R=0.0713 for 1388 non-zero reflections for the latter). The former molecules is not iso-structural with its nickel analog. The central palladium atom has trans-square planar geometry [Pd–Cl 2.304(5) and 2.297(5), Pd–P 2.344(4) and 2.361(5) Å]. The molecule has an approximate two-fold symmetry around the normal to the coordination plane. The neomenthyl groups are on the same side of the co-ordination plane. The latter molecule has exact C2 symmetry: the two-fold axis passes through the Cl(1), Pd, and Cl(2) atoms which lie on the co-ordination plane. The geometry around the palladium slightly deviates from the trans-square planar [Pd–Cl 2.296(9) and 2.267(9) Å and Pd–P 2.310(6) Å]. The menthyl groups are located on either side of the co-ordination plane.
Spectrophotometric Determination of Iron(III) and Aluminium with Semimethylxylenol Blue
Authors: Ueda Joichi 
Published: July 2006

Abstract
Semimethylxylenol Blue (SMXB) reacts with iron(III) and aluminium to form water-soluble colored complexes. The colored solution of the iron(III) complex shows a maximum absorption at 580–581 nm, while that of the aluminium complex shows it at 554–555 nm. The absorbances of the solutions are constant over the pH range from 1.2 to 1.5 and from 2.5 to 2.9, respectively. Beer’s law is obeyed up to 1.4 μg cm−3 of iron(III) and 1.0 μg cm−3 of aluminium. Their molar extinction coefficients are 3.38×104 and 2.91×104, respectively. As a result of the investigation of the composition of the iron(III) or aluminium complex, the mole ratio of metal and SMXB was estimated to be 1 : 1. Among the 45 diverse ions examined, gallium, tin(IV), bismuth(III), zirconium, and vanadium(V) interfered with iron(III) determination, and gallium, indium, bismuth(III), scandium, titanium(IV), zirconium, vanadium(V), iron(III), fluoride, and oxalate interfered with aluminium determination. Consecutive determination of iron(III) and aluminium was also studied.
Experimental Studies of the Liquid Junction Potential between Electrolyte Solutions in Different Solvents. I. Water–Organic Solvent Junctions
Authors: Izutsu Kosuke , Nakamura Toshio , Kitano Toshihiko , Hirasawa Chieko 
Published: July 2006

Abstract
The liquid junction potential (ljp) between water and organic solvents was investigated by measuring the emfs of cells with free-diffusion junctions of various electrolyte solutions. In most experiments, the concentration of the electrolyte on one side of a junction was kept much larger than that on the other side (c MX in S⁄⁄c′ M′X′ in S′; S or S′ is H2O and c&gt;&gt;c′; thus the ljp was mainly determined by MX. The ljp may practically be expressed by the sum of Ej,ion (concn)(I), Ej,ion (ion-solv.)(II), and Ej,solv. (III). I and II are contributions from ionic species: I is the concentration term, which can be estimated approximately from the Henderson equation, and II is the term due to the difference in ionic solvations in S and S′. III is the contribution from the transfer of solvent molecules. The sum of II and III for the case in which S=H2O is approximately equal in absolute value but opposite in sign to that for the case in which S′=H2O. The change of II with the anion X− is in linear relation with free energy of transfer of the anion from S to S′. The change of III with the bridge solvent is also a linear function of the heat (or free energy) of solution of S into S′. The rate of the change with the heat of solution can be divided in two classes by the species of the cation M+: the rate for R4N+ ions is just a half of that for such ions as Li+, Na+, Mg2+, and Ba2+. The effect of the mixed bridge electrolytes and the mixed bridge solvents was also examined.
Regioselective, Abnormal Ring Opening of the Epoxide of Quinone Epoxide–Cyclopentadiene Adducts
Authors: Ichihara Akitami , Kobayashi Makio , Oda Kengo , Sakamura Sadao 
Published: July 2006

Abstract
Treatment of quinone epoxide–cyclopentadiene adducts with sulfuric acid gave abnormal ring opening products, whose structures were determined by the spectral data and identification of the degradation product. Regioselectivity of the reaction was confirmed. The mechanism of the reaction is discussed.
Evidence of Existence of Two Stereospecific Control Mechanisms in Asymmetric Transformation of 2-Phenylpropanal via Enamines
Authors: Matsushita Hajime , Tsujino Yasuko , Noguchi Masao , Saburi Masahiko , Yoshikawa Sadao 
Published: July 2006

Abstract
The temperature dependence of asymmetric transformation of 2-phenylpropanal via achiral enamine salt of d-10-camphorsulfonic acid was examined. The relation between the rotation of 2-phenylpropanal obtained and reaction temperature showed a notable change in specific rotation of the aldehyde obtained. Two courses are postulated for the optical activation.
Nucleoside Analogs. 5. Synthesis of Carbocyclic Pyrimidine Nucleoside Analogs
Authors: Tadano Kin-ichi , Horiuchi Sumio , Suami Tetsuo 
Published: July 2006

Abstract
Six carbocyclic analogs of uridine and thymidine in which the pentofuranosyl groups are replaced by a carbocyclic cyclopentane system have been synthsized. Their biological activities were determined against HeLa S3 cells.
Photochemical Reactions of 2-(Alkoxycarbonyl)-, 2-Cyano-, and 2-(Phenylthio)-cycloalkanones in Alcoholic Solution. Formation of ω-Substituted Esters
Authors: Tokuda Masao , Watanabe Yasuyuki , Itoh Mitsuomi 
Published: July 2006

Abstract
Photochemical reaction of ethyl 2-oxo-1-cyclohexanecarboxylate (3) in methanol gave ethyl methyl heptanedioate, trans- and cis-ethyl 7-oxo-2-heptenoate, and ethyl 7-oxo-3-heptenoate in 25, 7, 8, and 21% yields, respectively. Photochemical reactions of 3 in ethanol, isopropyl alcohol, and t-butyl alcohol gave the corresponding ω-alkoxycarbonyl esters. Other 2-(alkoxycarbonyl)-cyclopentanones and -cycloheptanone underwent similar reactions to give the corresponding ω-alkoxycarbonyl esters. Photochemical reactions of 2-cyanocyclohexanones in methanol similarly gave ω-cyano esters and ω-formyl α,β-unsaturated nitriles. However, photochemical reactions of 2-(phenylthio)- and 2-(methylthio)cyclohexanones in methanol did not give the corresponding ω-phenylthio or ω-methylthio carboxylic acid esters, products resulting from a preferential cleavage of a carbon-sulfur bond being obtained.
Fluorescence of the Hindered Phenoxyl Radical
Authors: Okamura Tadashi , Yip R W 
Published: July 2006

Abstract
Fluorescence and excitation spectra of the 2,4,6-tritertiarybutylphenoxyl radical which is stabilized by a steric hindrance have been measured in benzene at room temperature. The emitting state seems to correspond with a state visualized in the excitation spectrum.
Magnetic Study of α- and β-Diamminecopper(II) Chlorides and Bromides
Authors: Asai Takeshi , Saheki Hiroshi , Hori Kayako , Kiriyama Ryôiti 
Published: July 2006

Abstract
The magnetic susceptibilities, χ, of α- and β-Cu(NH3)2X2(X=Cl, Br) were measured from 4.2 to 360 K. Those of β-Cu(NH3)2X2 obeyed the Curie-Weiss law above 50 K. The Weiss constants and effective Bohr magneton numbers are −3.5(±1) K and 1.75(±0.01) for X=Cl, and −9.7 K and 1.82 for X=Br. α-Cu(NH3)2Cl2 showed a rounded maximum for χ at 30 K. A linear Heisenberg model with the parameters, J=−23.5(±1) K and g=2.03(±0.03), gave good agreement with observations. α-Cu(NH3)2Br2 had a peak for χ at 47(±2) K. This temperature is probably a Neèl temperature. The strong magnetic interaction of the α-form compounds is related to the compressed coordination octahedron of [Cu(NH3)2X4]2−. All samples used were solid solutions of Cu(NH3)2X2 and NH4X. An analysis of χ suggests that the Cu2+ cations in α-Cu(NH3)2Cl2 are distributed inhomogeneously over a short range. A similar inhomogeneity was also found for the β-Cu(NH3)2X2 samples. In this sense, the β-form may be better described as a solid solution of α-Cu(NH3)2X2 and NH4X rather than as a dimorph.
ESR Studies of Oxygen, Sulfur Oxide, and Sulfur Radicals Adsorbed on NaX Zeolite
Authors: Kanzaki Natsuko , Yasumori Iwao 
Published: July 2006

Abstract
The states of O2 and SO2 adsorbed on NaX zeolite were investigated by means of ESR. No oxygen anion radicals were formed thermally on NaX up to 773 K. The adsorption of O2 on γ-irradiated NaX in a vacuum, however, resulted in an ESR spectrum due to O2−. Several kinds of O2− species and O3− were found to be formed on NaX by γ-irradiation in the presence of O2. These oxygen anion radicals showed different reactivities with N2O, ethylene and propylene, and transferred electrons to SO2 to form SO2−. The SO2− radical was also produced on NaX by raising the temperature from 298 to 573 K after the introduction of SO2. This reacted with O2 to form a radical, like SO4−, but upon evacuating the O2, the reaction was reversed to give the original SO2−. When the temperature of NaX was further raised to 773 K in the presence of SO2, a spectrum assigned to a polyatomic sulfur radical appeared indicating that SO2 decomposition occurred at high temperature. This polymer radical was stable in an O2 atmosphere at room temperature.
Far-infrared Spectra of Low- and High-temperature Phases of CsCuCl3
Authors: Akiyama Kenji , Morioka Yoshiyuki , Nakagawa Ichiro 
Published: July 2006

Abstract
Polarized far-infrared reflection spectra of the CsCuCl3 single crystal have been recorded with the electric vector parallel and perpendicular to the c axis at room temperature. Polarized far-infrared transmission spectra have been measured at liquid-nitrogen temperature. The observed spectra have been interpreted using the factor group analysis based on the space group D62. Far-infrared transmission spectra of the powder sample have also been measured over the temperature range from 175 °C to liquid-nitrogen temperature. The spectrum at 175 °C consists of five bands and reveals a typical feature characteristic of the CsNiCl3 structure (D6h4). The spectral change due to the phase transition has been interpreted based on the structural distortion of the crystal.
Fluorescence Quenching of Naphthalene and Its Derivatives by Acetyl Chloride
Authors: Tamaki Takashi 
Published: July 2006

Abstract
The fluorescence of naphthalene and its methyl or methoxy derivatives has been found to be quenched by acetyl chloride. The quenching constants, determined by the Stern-Volmer treatment of the emission intensity and lifetime have been found to be in good agreement within experimental error. The quenching rate constants have been correlated with the energy terms of electron-donating forces in the excited states of these naphthalenes. The results suggest that the quenching mechanism involves a charge-transfer stabilized complex, in which the excited naphthyl compounds act as donors. Exciplex formation has been supported by oxygen quenching experiments.
Preparative Study on Chiral Orthotelluratobis(diamine)cobalt(III) Complexes and Their Condensation Products
Authors: Hosokawa Yutaka , Shimura Yoichi 
Published: July 2006

Abstract
Five chiral cobalt(III) complexes coordinating an orthotellurate or a ditellurate ligand have been prepared and their optically active isomers isolated. They belong to one of the three following types: first a “mononuclear” [Co(TeO6H4)(diamine)2]+ type (diamine=ethylenediamine (en) and (R)-(−)-1,2-propanediamine); second a “dinuclear” [Co(diamine)2(Te2O10H4)Co(diamine)2]2+ one (diamine=en and (R,R)-(−)-trans-1,2-cyclohexane-diamine); and lastly a “tetranuclear” [{Co(diamine)2}2(Te2O10){Co(diamine)2}2]4+ one (diamine=en). The structures of these complexes have been discussed from the visible to ultraviolet absorption and circular dichroism spectra.
Synthesis and Electrical Resistivity of Bis(dialkyldithiocarbamato)gold(III) Cation-TCNQ Radical Anion Salts
Authors: Yumoto Yoshiji , Kato Futoshi , Tanaka Toshio 
Published: July 2006

Abstract
Seven simple salts and one complex salt of TCNQ\ewdot radical anion with bis(dialkyldithiocarbamato)gold(III) cations, [Au(S2CNR2)2]+TCNQ\ewdot (R=Me, Et, n-Pr, n-Bu, n-C6H13, n-C8H17, and CH2C6H5) and [Au(S2CN(CH2C6H5)2)2]+(TCNQ)2\ewdot, were prepared. The complex salt was also obtained as an acetonitrile solvate, [Au(S2CN(CH2C6H5)2)2]+(TCNQ)2\ewdot·MeCN. The electrical resistivity of the simple salt with R=CH2C6H5 (2.9×104 ohm cm in compacted sample) is much lower than those of the remaining simple salts (1.1×107–2.2×1010 ohm cm). The resistivities of two complex salts are in the order of 102 ohm cm. Electronic absorption spectra and magnetic susceptibility measurements in the solid state indicate that the simple salts with R=Me, Et, n-Pr, n-C6H13, and CH2C6H5 involve the TCNQ\ewdot radical anion monomer, whereas those with R=n-Bu and n-C8H17 involve dimeric (TCNQ)22−. The interaction between TCNQ\ewdot radical anion and neutral TCNQ in the complex salts is extremely weak, as suggested from no appreciable absorption band in the near-infrared region.
Formose Reactions. VI. Formose Synthesis in Methanol
Authors: Shigemasa Yoshihiro , Matsuda Yoshinobu , Sakazawa Chikahiro , Nakashima Ruka , Matsuura Teruo 
Published: July 2006

Abstract
The formose reaction in methanol was compared with that in an aqueous solution. The reaction can occur in aqueous methanol even at a low [CaO]/[HCHO] ratio (0.05), at which the reaction does not take place in an aqueous solution, and the formaldehyde consumption rate decreases with an increase in the methanol concentration. Contrary to the formose reaction in an aqueous solution, the sugar yield in methanol becomes higher with an increase in the formaldehyde concentration. The rates of the sugar degradation and the formaldehyde consumption increase with an increase in the pH. The distribution of products is different from that in an aqueous solution, but both of them are very complex and essentially nonselective.
Effect of Pressure on the Rates of Solvolysis. Hydrolysis of Some Sterically Hindered Chlorides
Authors: Sera Akira , Takeuchi Shinichi , Tachikawa Noboru , Maruyama Kazuhiro 
Published: July 2006

Abstract
The effect of pressure on the rates of solvolyses of substituted 1-phenylethyl and benzyl chlorides has been investigated in an ethanol–water mixture at 25 °C. The activation volumes have been calculated and the dependence of these values on the number and size of the substituents have been interpreted in terms of the competitive contribution of the steric inhibition of resonance and steric hindrance to solvation in the transition states.
Reactive Troponoids and o-Aminophenol. III. The Reaction of 2-Bromo-7-methoxytropone
Authors: Nozoe Tetsuo , Someya Taichi , Okai Harue 
Published: July 2006

Abstract
The reaction of 2-bromo-7-methoxytropone with o-aminophenol gave 2-bromo-7-(o-hydroxyanilino)tropone (9), besides small amounts of cyclohepta[b][1,4]benzoxazin-6(11H)-one (10) and 15H-[1,4]benzoxazino[3′,2′ : 3,4]cyclohepta[2,1-b][1,4]benzoxazine (11). The heating of 9 with a strong acid afforded 6-bromocyclohepta[b][1,4]benzoxazine (13) quantitatively. On the other hand, the heating of 13 with o-aminophenol in ethanol gave 10, while in acetic acid a mixture of 10 and 11 was obtained. The mechanism of the formation of these products is discussed.
Optical Activity and Absolute Configuration of 5,6,11,12-Tetrahydro-2,3,8,9-tetramethoxy-5,11-methanodibenzo[a,e]cyclooctatetraene
Authors: Ogura Fumio , Nakao Akio , Nakagawa Masazumi 
Published: July 2006

Abstract
The title compound (VII) was synthesized in an optically active form and the chiroptical properties were recorded. The absolute configuration was determined by chemical correlation method.
Carbon-13 NMR Spectra of Di-t-alkyl Ethers and Related Hindered Ethers
Authors: Masada Hiromitsu , Murotani Yoshiharu 
Published: July 2006

Abstract
The C-13 NMR spectra of hindered t-alkyl ethers and dineopentyl ether have been presented and the electronic and steric effects discussed. The resonances for the α-, methylene β-, and methyl β-carbons of di-t-alkyl ethers shifted downfield by +45, +1.2, and −0.2 ppm, respectively, relative to the corresponding alkanes.
An X-Ray Diffraction Study on the Structure of Hexa-amminecadmium(II) Ion in Aqueous Solution
Authors: Yamaguchi Toshio , Ohtaki Hitoshi 
Published: July 2006

Abstract
The structure of the hexaamminecadmium(II) ion in an ammoniacal aqueous solution of cadmium chloride was determined by the X-ray diffraction method at the NH3/Cd mole ratio of 9.9. The result showed that a cadmium(II) ion is octahedrally surrounded by six ammonia molecules at the distance of (2.37±0.03) Å.
Asymmetric Synthesis of Alanine by Hydrogenolytic Asymmetric Transamination between (R)-2-Amino-2-phenylethanol and Ethyl Pyruvate
Authors: Harada Kaoru , Tamura Minoru 
Published: July 2006

Abstract
Hydrogenolytic asymmetric transamination between (R)-2-amino-2-phenylethanol and ethyl pyruvate was studied. The optical purity of the resulting alanine was in the range 10–62 %. The effect of solvents and the asymmetric moieties in the syntheses were explained by the chelation hypothesis based on the substrate-catalyst complex.
The Reductions of Carbonyl Compounds with Sodium 1-Benzyl-3-carbamoyl-1,4-dihydropyridine-4-sulfinate
Authors: Inoue Hiroo , Sonoda Ichiro , Imoto Eiji 
Published: July 2006

Abstract
It is found that sodium 1-benzyl-3-carbamoyl-1,4-dihydropyridine-4-sulfinate reduces α-keto carbonyl compounds to α-hydroxy carbonyl compounds with the assistance of MgCl2 and reacts with 9-fluorenone to give an adduct.
High Performance Liquid Chromatographic Analysis of Individual Bile Acids: Free, Glycine- and Taurine-conjugated Bile Acids
Authors: Okuyama Sumihiko , Uemura Daisuke , Hirata Yoshimasa 
Published: July 2006

Abstract
High performance liquid chromatographic analyses of individual bile acids (cholic, chenodeoxycholic, deoxycholic, and lithocholic acids), free and conjugated with glycine and taurine, are described. The analyses of the free and glycine-conjugated bile acids are based on the esterification of the carboxyl group of bile acids with O-(p-nitrobenzyl)-N,N′-diisopropylisourea(PNBDI). The bile acids in the biological samples were extracted by an Amberlite XAD-2 column, and separated by DEAE-Sepharose CL-6B into free, glycine and taurine-conjugated bile acids. After separation, the free and glycine-conjugated bile acids were directly esterified with PNBDI. Taurine-conjugated bile acids are unable to be esterified with PNBDI, the bile acids were hydrolyzed with NaOH to produce the free bile acids, and then esterified. The p-nitrobenzyl ester of bile acids has a characteristic ultraviolet absorption. Consequently the compounds were separated into the individual bile acids by high performance liquid chromatography, and detected by an UV-detector. An analysis of the individual bile acids in human bile is given for an example.
The Silver(I) Salt-promoted Benzylation of Silyl Enol Ethers
Authors: Takagaki Hidetsugu , Yasuda Nobuyoshi , Asaoka Morio , Takei Hisashi 
Published: July 2006

Abstract
Various silyl enol ethers gave the corresponding mono benzyl products in moderate to good yields by the reaction with benzyl bromide in the presence of silver perchlorate in dichloromethane at −78–0 °C.
Investigation of CdS Photoanode Reaction in the Electrolyte Solution Containing Sulfide Ion
Authors: Inoue Tooru , Watanabe Tadashi , Fujishima Akira , Honda Kenichi 
Published: July 2006

Abstract
The study of the photoanodic reaction in the CdS/S2− system was carried out by means of the rotating ring-disk electrode (RRDE) technique. The photoanodic reactions at an n-type CdS electrode are divided into two types; the photoanodic oxidation of redox agents in the electrolyte solution and the photoanodic dissolution of CdS electrode surface. The stabilization of a CdS photoanode could be attained through the preferential progress of the former of these two processes. The ratio between these two processes depends upon the concentration of S2− in the electrolyte solution and the light intensity. Sulfide ion in the electrolyte solution stabilizes CdS photoanode and gives rise to the shift of the flatband potential of CdS electrode by ca. −60 mV/log[S2−]. This dependence of the flatband potential on sulfide ions can be explained by an adsorptive dissociation equilibrium at a CdS electrode surface. The results of the photoanodic reaction were disscussed referring to the charge transfer process with the participation of some surface energy state within a bandgap.
The Visible-UV Absorption and Circular Dichroism Studies of Poly(α-l-glutamic acid)–Copper(II) Complexes with Emphasis on the Extrinsic Cotton Effect
Authors: Yamaoka Kiwamu , Masujima Tsutomu 
Published: July 2006

Abstract
The visible-UV absorption and circular dichroism, CD, of poly(α-l-glutamic acid)–Cu(II) solutions have been measured at 25 °C in the pH range 7 to 3.5 and at the mixing ratio, R, (Glu residues-to-Cu2+) 32 to 4. Complex formation between poly (Glu) and Cu2+ was evident from the three absorption bands of bound Cu(II) around 700, 370, and 250 nm. The molar absorption coefficients, ε, varied with pH and R in a complicated but systematic manner. The pH dependence of ε, however, was not in parallel with the helix-coil transition of poly(Glu)–Cu(II) complexes. The extrinsic CD bands of bound Cu(II) have been detected in the three absorption band regions, and found to depend on both pH and R. The optical dissymmetry factor indicated that the 700 and 250 nm absorption bands of bound Cu(II) are associated with multiple CD bands of opposite signs. The intrinsic CD showed that the Cu(II)- and pH-induced helices of the poly(Glu)–Cu(II) complex are alike regarding the polymer backbone.
Electrical Properties of a One-dimensional Conductor, NaxV2O5
Authors: Kobayashi Hayao 
Published: July 2006

Abstract
The resistivity measurement, DTA analysis, refinement of the crystal structure, and examination of the X-ray diffuse scattering have been carried out on the β-phase of the sodium vanadium bronze. A resistivity minimum was observed around 200 K. The peak position of the logarithmic derivative of the resistance and an anomaly in the DTA curvature indicate that a metal-insulator transition occurs at about 130 K. The X-ray diffuse scattering shows a tendency of the sodium atoms toward cluster formation. It is concluded that the β-phase of sodium vanadium bronze is neither a simple one-dimensional metal nor a simple semiconductor, but can be-have partly as a one-dimensional metal and partly as an anisotropic semiconductor.
Precise Coulometric Titration of the Potassium Hydrogen Phthalate (NBS-SRM 84d). The Use of the Faraday Constant as an International Standard
Authors: Yoshimori Takayoshi , Tanaka Tatsuhiko 
Published: July 2006

Abstract
The purity of the potassium hydrogen phthalate (NBS SRM 84d) was determined by precise coulometric titration. The purity obtained was 99.995±0.002% (standard deviation: 0.003%), and was in excellent agreement with the purities of the same SRM determined already in three laboratories in U.S.A. These results support the recommendation on the use of the Faraday constant as an international standard for titrimetric analysis.