bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infrared Absorption Spectra of Silica Gel-H216O, D216O, and H218O Systems
Authors: Hino Masao , Sato Toshio 
Published: July 2006

Abstract
Infrared absorption spectra of the systems of silica gel - H216O,D216O,H218O, and some organic vapors were measured in order to assign the bands senstive to adsorption at 870 and around 950 cm−1. Deuteration of silica gel caused the absorption decrease at 870 cm−1 and the appearance of a band at 620 cm−1. The band around 950 cm−1 appearing by adsorption not only of water but also of organic vapors showed no shift on deuteration, but shifted toward low frequency side by 25 cm−1 on the substitution of 16O of surface silanol groups with 18O. From these facts the bands at 870, 620 and 950 cm−1 were assgned to Si–OH bending, Si–OD bending and Si–O stretching vibrations of surface silanol groups, respectively. The oxygen atom of silanol groups of silca gel was found to exchange with that of adsorbed water molecules even at room temperature for a sample treated at temperature below 300°C. On the other hand, higher reaction temperature of ca. 200°C was necessary for a sample calcined at 800°C. mechanism of the oxygen atom exchange recation was discussed.
A Nuclear Magnetic Relaxation of 139La in Ionic Aqueous Solutions
Authors: Nakamura Keikichi , Kawamura Kazutaka 
Published: July 2006

Abstract
The nuclear magnetic relaxation rates of the 139La ion in aqueous solutions of halides, nitrate, sulfate, and perchlorate have been measured. The observed relaxation rates increased as the concentration of the salts increased. However, in the low concentration range, the relaxation rate divided by the relative viscosity, Δv/ηr increased only in the cases of nitrate and sulfate, while it decreased in the cases of halides and perchlorate. It was found that the formation of inner-sphere complexes is a satisfactory explanation of the increase in the Δv/ηr of nitrate and sulfate solutions in the low to middle concentration range. With the fact, proved by various authors, that the lanthanide ions have several coordination numbers, the decrease in the Δv/ηr of halide and perchlorate solutions in the same concentration range can be explained in terms of the existence of an equilibrium between two hydrated species, such as:
La(H2O)93+\ightleftharpoonsLa(H2O)83++H2O
and the symmetrical species, La(H2O)83+, contributes to the decrease in Δv/ηr. At a high nitrate concentration, after reaching the maximum value Δv/ηr decreases, demonstrating that a symmetrical trinitrato species may be formed in the solution.
Dynamic Behaviors of the Electron Donor-Acceptor Complex in its Lowest Excited Singlet State
Authors: Masuhara Hiroshi , Shimada Motoo , Tsujino Nobuyuki , Mataga Noboru 
Published: July 2006

Abstract
Dynamic behaviors of the weak electron donor-acceptor (EDA) complex in its lowest excited singlet state have been investigated by the nsec flash photolysis method and measurements of fluorescence and transient photocurrent. In polar solvents the weak EDA complex in its lowest excited singlet state dissociates spontaneously into ions. The dynamic behaviors of s-tetracyanobenzene(TCNB)-benzene and TCNB-toluene complexes were studied in some solvents and the existence of the direct radiationless process at the excited Franck-Condon (FC) state as well as in the course of relaxation process from the excited FC state to the fluorescent state has been confirmed in the case of 1,2-dichloroethane solution. The nature of the intra-complex radiationless processes was discussed on the basis of this result. It has been pointed out that the lifetime of excited states is of crucial importance for understanding the dynamic behaviors of excited weak EDA complexes.
Charge-Transfer and Proton-Transfer in the Formation of Molecular Complexes. I. The Complex Isomerization of Some Anilinium Picrates by Melting
Authors: Saito Gunzi , Matsunaga Yoshio 
Published: July 2006

Abstract
o-Chloroaniline, m-nitroaniline, 3-nitro-4-methylanilme, and N,N-dimethylamino-p-benzaldehyde form true phenolates with picric acid. However, their electronic and vibrational spectra were found to be drastically modified by melting. The appearance of a new electronic absorption located near the place where the corresponding s-trinitrobenzene complex exhibits the charge-transfer band is noted above the melting point. At the same time, the vibrational bands due to the anilinium ion observed at room temperature are replaced by those due to the aniline. On the basis of these observations, it was concluded that complex isomerization from a true phenolate to a charge-transfer complex takes place by melting in these cases. On the other hand, the spectra of N,N-diethylanilinium and m-chloroanilinium picrates were shown to remain the same below and above the melting points.
The Electron Spin Resonance of Binuclear Vanadyl Tartrates
Authors: Hasegawa Akinori , Yamada Yoshio , Miura Masaji 
Published: July 2006

Abstract
The ESR spectra of aqueous solutions of binuclear vanadyl tartrates remarkably varied with their pH values. This variation was found to be directly correlated with the change in the form of the carboxyl group, i.e. whether it was dissociated or acidic. Thus, the frozen solution spectra were observed in water-ethylene glycol at 77°K and analyzed in terms of several magnetic parameters containing the parameter of magnetic dipolar interaction, D. From these D values, the intramolecular V···V distances were estimated to be ca. 4.2, 5.2, and 6.5Å in the solutions at pH 9, 4.8, and 2.8 respectively. Such a remarkable change in the V···V distances as interpreted to be caused by the dissociation of the coordinate bonds between the vanadium atom and the carboxyl oxygen atom and the change in the molecular structure of the tartrates, brought about the change in the form of the carboxyl groups.
The Semiconductive Property and the Phase Transition of the [(C6H5)3PCH3]+(TCNQ)2\ewdot Anion Radical Salt. The Entropy Change Due to Electrons and Holes
Authors: Iida Yôichi 
Published: July 2006

Abstract
The semiconductive organic crystal of [(C6H5)3PCH3]+(TCNQ)2− is known to undergo a first-order phase transition at 315.7°K. The discontinuity in the temperature dependence of the electrical conductivity takes place at the transition temperature, above which the populations of the electrons and the holes in the electrical conductivity increase abruptly. A theoretical consideration of the system of conduction carriers in an intrinsic semiconductor was developed in order to evaluate the entropy change of the electrons and holes at the phase transition. For [(C6H5)3PCH3]+ (TCNQ)2−, this kind of entropy change was found to be much less than the total entropy change determined from the heat-capacity measurements by Kosaki et al. In view of these results, it was concluded that the anomaly in the electrical conductivity was induced by the change in the crystal structure.
The Solvent Effect on the Electron-Transfer Reactions of Cobalt(III) Complexes. The Reduction of the cis-Chloro-2-aminoethanolbis(ethylenediamine)cobalt(III) Ion by Iron(II) in Aqueous Solutions of Organic Solvents
Authors: Ohashi Kousaburo , Yamamoto Katsumi , Suzuki Toshio , Kurimura Yoshimi 
Published: July 2006

Abstract
The solvent effect on the reduction of the textitcis-chloro-2-aminoethanolbis(ethylenediamine)cobalt(III) ion by iron(II) was investigated in aqueous solutions of dimethylsulfoxide (DMSO), dimethylformamide (DMF), ethanol, and acetone. The second-order rate constants for the reduction are 4.4×10−5 m−1sec−1 in the absence of an organic solvent, 1.4×10−3 m−1sec−1 in 0.20 Mf DMSO, 7.3×10−4 m−1sec−1 in 0.20 Mf DMF, 1.1×10−4 m−1sec−1 in 0.20 Mf ethanol, and 1.0×10−4 m−1sec−1 in 0.20 Mf acetone, at 25°C and at 0.16 m HClO4 and Σ[ClO4−]=0.60 m (Mf= mol fraction of organic solvent). From the kinetic and spectral data, it is suggested that the increase in the rate upon the addition of an organic solvent may be mainly due to a change in the solvation sphere of the reductant by replacing the water molecules by the organic molecules.
Gas-Chromatographic Determination of Ultramicro Amounts of Selenium in Pure Tellurium Metal
Authors: Shimoishi Yasuaki 
Published: July 2006

Abstract
Selenium (IV) reacts with 4-nitro-o-phenylenediamine to form 5-nitropiaselenol, which is detected by means of a gas chromatograph equipped with an electron-capture detector. By this highly sensitive method, the selenium in pure tellurium metal (99.9–99.999%) can easily be determined. Aqua regia oxidizes both selenium and tellurium to the quadrivalent state, and no loss of selenium is found upon this treatment. This method requires only 10–30 mg of a tellurium sample, and the presence of foreign ions does not interfere. It was found that pure tellurium, commercially available, always contains 10−3–10−4% selenium.
The Stereochemistry of Nucleophilic Addition. II. The Reformatsky Reaction of Methyl (+)-α-Bromopropionate, 2-Phenylpropanal, and 3-Phenyl-2-butanone
Authors: Matsumoto Takashi , Tanaka Isao , Fukui Kenji 
Published: July 2006

Abstract
The Reformatsky reaction of methyl (+)-α-bromopropionate with benzaldehyde was carried out in order to study the reaction mechanism, and two epimeric methyl 3-hydroxy-2-methyl-3-phenylpropionates (IIa and IIb) were obtained in a 59 : 41 ratio. From a comparison of the optical activity of IIb with that of pure (−)-IIb, it was estimated that lib consists only seven percent of an optically-active compound; this results supports the hypothesis of the enolate anion mechanism. Subsequently, the stereochemistry of this reaction with 2-phenyl-propanal (IV) and 3-phenyl-2-butanone (VIII) was studied. The condensation of IV with methyl bromo-acetate gave a mixture of the epimeric methyl 3-hydroxy-4-phenylvalerates (Va and Vb), which were separated in a 26 : 74 ratio by means of column chromatography on silica gel. Similarly, VIII was also condensed with methyl bromoacetate to give the epimeric methyl 3-hydroxy-3-methyl-4-phenylvalerates (IXa and IXb) in a 31 : 69 ratio. The configurations of these esters were assigned by correlation with the products of the Grignard reaction, the stereochemistry of which is well known. From the present study, it is clear that the Reformatsky and the Grignard reactions of the carbonyl compound having an asymmetric α-carbon atom proceed in a similar fashion; that is, the entering group predominantly approaches the carbonyl group from the least-hindered side. Therefore, Gram’s rule of asymmetric induction can be applied in the stereochemistry of the Reformatsky reaction.
Stereochemical Studies in Friedel-Crafts Reactions. I. The Reactions of cis-and fraws-4-Tetrahydrophthalic Acid and Its Dimethyl Ester with Benzene
Authors: Sugita Kaichiro , Tamura Shuzi 
Published: July 2006

Abstract
The aluminum chloride-catalyzed reactions of cis-Δ4-tetrariydrophthalic acid (1A) and its dimethyl ester (3A) with benzene gave, stereoselectively, t-4-phenyl-cis-bexahydrophthalic acid (2A) and its dimethyl ester (12) respectively. Similarly, the reactions of trans-Δ4-tetrahydrophthalic acid (1B) and its dimethyl ester (3B) with benzene gave, stereoselectively, c-4-phenyWrtrans-hexahydrophthalic acid (2B) and its dimethyl ester respectively, accompanied by a small amount of the c-4,t-2,r-1-isomer. The mechanism can be explained by presuming the interaction of the lone-pair electrons of carbonyl oxygen in the axial carboxyl group with a vacant p-orbital of the carbonium ion, which is produced by protonation to the double bond of the cyclohexenes (1A, 1B, 3A, 3B).
Stereochemical Studies in Friedel-Crafts Reactions. II. The Reactions of 4-Substituted Cyclohexenes with Benzene
Authors: Sugita Kaichiro , Tamura Shuzi 
Published: July 2006

Abstract
The addition reactions of benzene to the double bonds of 4-substituted cyclohexenes, such as 4-benzoyl-cyclohexene (5), 4-acetylcyclohexene (6), methyl 4-cyclohexenecarboxylate (7), and 4-cyclohexenecarboxylic acid (8) have been studied in the presence of aluminum chloride. In all cases, the reactions gave mainly 1,4-disubstituted cyclohexane with the trans configuration stereoselectively. A possible mechanism for this reaction is suggested.
Studies on Separation of Amino Acids and Related Compounds. V. A Racemization Test in Peptide Synthesis by the Use of an Amino Acid Analyzer
Authors: Izumiya Nobuo , Muraoka Masako , Aoyagi Haruhiko 
Published: July 2006

Abstract
Several tripeptides, H-Gly-Dl-Ala-B-OH, in which B residues are Dl-alanine, l-valine, l-leucine, l-phenyl-alanine, l-proline, and l-serine have been synthesized and the separation of each glycyltripeptide diastereomers by an amino acid analyzer have been studied. Among six peptides studied, diastereomeric mixtures of H-Gly-Dl-Ala-l-Val-OH and H-Gly-Dl-Ala-l-Leu-OH were separated completely. A procedure to determine the amounts of Ll and Dl diastereomer of H-Gly-Ala-Leu-OH by the use of the analyzer was developed, and this procedure was applied to examine the influence of coupling reagents for racemization during coupling of benzyl-oxycarbonyl-glycyl-l-alanine and l-leucine benzyl ester by several reagents.
The Carboxylation Reaction using Nickel Catalysts. V. The Catalytic Reaction of Propene with Nickel Carbonyl and Nickel Carbonyl-Triphenylphosphine
Authors: Kunichika Sango , Sakakibara Yasumasa , Okamoto Tadashi , Takagi Kentaro 
Published: July 2006

Abstract
The carboxylation reaction of propene catalyzed by nickel carbonyl was studied undeer various conditions. Iso- and n-butyric acids were obtained in good yields under mild conditions in the presence of a large amount of an organic acid. The catalytic carboxylation area was examined in detail. The carboxylation reaction proceeded smoothly in tetrahydrofuran, acetic acid, and dioxane. The proportion of isobutyric acid was largest in acetic acid (72.5–77.5%). Triphenylphosphine (TPP) had a great effect on the reaction rate, the catalytic reaction area, and the product distribution. On the reaction mechanism, an active species (HNi(CO)(TPP)X) was taken to account for the experimental results.
Mechanistic Studies on the Photochemical Oxidation of Phenothiazine with Oxygen in Ethanol
Authors: Iwaoka Teiki , Kokubun Hiroshi , Koizumi Masao 
Published: July 2006

Abstract
It has been established that phenothiazine (PTH) undergoes photooxidation, PTH+O2\oversethν→PT·+HO2 in the aerated ethanol (dehydrated!) yielding a neutral radical as a stable product. The reaction is a one photon process and the reactive state is triplet PTH. It has further been established that the reaction occurs via a molecular complex (PTH-O2) most likely of C-T type, which has the absorption at ∼385 nm and decays with the first order rate constant of 1.6×102 sec−1. A similar transient C-T complex has been found to be produced from triplet PTH and dimethylisophthalate (weak electron acceptor) (absorption ∼385 nm, decay constant 2×103sec−1) with almost the diffusion controlled rate constant, although the eventual reaction does not occur. Thus in case of (PTH-O2), reaction (PTH-O2)→PT·+HO2 occurs while in case of (PTH-DMIP), the analogous reaction does not. Behavior of radical species (containing radical cation and (PTH-O2)) produced in the rigid aerated ethanol at 77°K has also been studied. The present C-T complex is interesting in the point that it is produced via triplet state of donor and has a rather long lifetime.
Conformations of the Esters. V. The Conformations of Carbonates
Authors: Oki Michinori , Nakanishi Hiroshi 
Published: July 2006

Abstract
In alkyl or aryl carbonates, the presence of conformational isomers (s-cis and s-trans) has been confirmed by infrared and nuclear magnetic resonance spectroscopic techniques. The dipole-moment measurements also support the conclusions obtained from the spectroscopic data.
Preparation of Carboxylic Esters and Phosphoric Esters by the Activation of Alcohols
Authors: Mitsunobu Oyo , Eguchi Masahiko 
Published: July 2006

Abstract
The reaction of dibenzyl hydrogen phosphate with alcohols in the presence of diethyl azodicarboxylate and triphenylphosphine, followed by catalytic hydrogenation, resulted in the formation of the corresponding alkyl dihydrogen phosphates. When p-tolyl dihydrogen phosphate and ethanol were allowed to react with diethyl azodicarboxylate and triphenylphosphine, ethyl p-tolyl hydrogen phosphate and diethyl p-tolyl phosphate were obtained. On the other hand, dipyridinium p-tolyl phosphate gave ethyl p-tolyl hydrogen phosphate and di p-tolyl pyrophosphate. The reaction of alkyl N,N′-tetraethylphosphorodiamidites with carboxylic acids in the presence of diethyl azodicarboxylate resulted in the formation of corresponding carboxylic esters. When these reactions (benzoylation) were carried out with the use of optically active 2-octanol, 2-octyl benzoate was obtained with inverted configuration.
Synthesis and the Iodine-Catalyzed Rearrangement of Isohibaene
Authors: Kitadani Masayuki , Ito Ken , Yoshikoshi Akira 
Published: July 2006

Abstract
A partial synthesis of isohibaene (VI) starting with nezukol (V) has been accomplished. It involves, as the key step, the intramolecular insertion reaction of a ketocarbene generated by cuprous oxide-catalyzed decomposition of diazoketone (XI) under irradiation. It has been found that isohibaene undergoes rearrangement into a mixture of phyllocladene (XIV) and isophyllocladene (XV) by iodine catalytically.
Studies of Hydroxy Amino Acids. II. The Separation of Diastereoisomers of Hydroxy Amino Acids
Authors: Ariyoshi Yasuo , Sato Naotake 
Published: July 2006

Abstract
It has been found that erythro-β-hydroxy-Dl-norvaline, and erythro-β-hydroxy-Dl-norleucine, and threo-β-hydroxy-Dl-leucine form scarcely-soluble compounds in water with α-naphthylphosphoric acid, tetrachlorophthalic acid, and chlorendic acid, respectively. On the other hand, the compounds of their diastereoisomers with the reagents were soluble in water. On the basis of these facts, β-hydroxy-Dl-norvaline, β-hydroxy-Dl-norleucine, and β-hydroxy-Dl-leucine were successfully separated into their diastereoisomers. The configurational assignment of α-amino-β-hydroxy acids without a branched side chain on the γ-carbon atom was established by means of NMR spectroscopy.
The Photochemistry of Large-ring Cycloalkanones
Authors: Matsui Kiyohide , Mori Takasi , Nozaki Hitosi 
Published: July 2006

Abstract
The photoreactions of 11-, 12-, and 13-membered cycloalkanones (Ia, Ib, and Ic) are described. The major products are cis, trans isomers of bicyclo[n.2.0]alkan-1-ol (n=7, 8, and 9; II, III). The stereochemistry and multiplicity of the reactive species have been discussed with emphasis on the effect of the ring size. The Ib cyclododecanone is most readily susceptible to the photochemical cyclization via its S1 state, affording the cis-cyclobutanol IIb stereoselectively.
Decomposition of Saturated Gaseous Hydrocarbons in Induction-Coupled Argon Plasma Jet
Authors: Nishimura Yukio , Satoh Arata , Takeshita Kenjiro , Sakai Wataru 
Published: July 2006

Abstract
The decomposition of methane, ethane, and isobutane has been studied in an induction-coupled argon plasma jet at atmospheric pressure. Methane was decomposed to give mainly acetylene, soot, and hydrogen, and to give the traces of ethylene and ethane. From the dependence of both the conversion of methane and the product distribution on methane feed rate, the input and argon flow rate, it was concluded that methane was not completely mixed with the plasma jet but the decomposition of methane took place mainly in the outer flame of the plasma jet and its surroundings. In the decomposition of ethane, ethylene, and methane were formed in 20–27% and 3–5% selectivity based on carbon, respectively, in addition to acteylene, soot, and hydrogen. In the decomposition of isobutane, propylene was produced in 10–14% selectivity based on carbon, besides the above mentioned products. From these results together with those on propane and n-butane,it was suggested that radicals formed by a fission of C–H or C–C bond played the main role in the decomposition of saturated gaseous hydrocarbons in the induction-coupled argon plasma jet.
The Electronic Structure of Zeise’s Salt, [PtCl3C2H4]−
Authors: Katô Hajime 
Published: July 2006

Abstract
A semiempirical SCF MO method including all the valence electrons in a molecule has been applied to Zeise’s salt, which is one of the most simple metal-olefin π-complexes. The electron-repulsion integrals are included explicitly in the present method. The results agree well with the available experimental data, indicating that the C-C bond order is equal to 1.545 and that the ethylene is tightly bound to platinum. An attempt to assign the observed bands to particular electron transitions has been made on the basis of a calculation of the transition energies and transition moments. We identify the band at 40700 cm−1 as the charge-transfer band corresponding to the electronic transition from ethylene to platinum. Several properties of Zeise’s salt are calculated, and much information on the bonding is obtained.
Diffuse Reflection Spectra of Filter Papers Dyed with 1-Arylazo-2-naphthols
Authors: Matsunaga Yoshio , Miyajima Nobuhiko 
Published: July 2006

Abstract
The diffuse reflection spectra of filter papers dyed with sixteen 1-arylazo-2-naphthols were examined in the range from 350 to 700 mμ. The absorption bands due to both the azo and hydrazone tautomers were observed in this state. Appreciable changes in the hue of the dyed papers caused by moisture were attributed to the deviation from the Kubelka-Munk theory due to the increased regular reflection; however, the movement of the tautomeric equilibrium caused by moisture was also clearly demonstrated in many cases. The direction was found to depend upon the kind and position of the substituents, e.g., towards the azo tautomer in the case of the p-Cl and o-NO2 derivatives and towards the hydrazone tautomer in the case of the m-Cl and o-MeO derivatives.
Low Frequency Infrared Absorption Bands of Water of Crystallization at Low Temperature
Authors: Fukushima Kunio 
Published: July 2006

Abstract
The low temperature infrared absorption spectra of water of crystallization of BaCl2·2H2O, CuCl2·2H2O and K2C2O4·H2O, which have water of crystallization in different bound states, were measured and compared with the room temperature spectra. Corresponding to the change of temperature of the samples, remarkable change in frequencies and intensities was observed for the bands due to the lattice vibrations associated with water of crystallization.
The Recombination of Iodine Atoms Generated by a C. W. Argon Ion Laser
Authors: Harada Naohiko , Mori Yuji , Tanaka Ikuzo 
Published: July 2006

Abstract
The rate constants of iodine-atom recombination in various foreign gases were determined by measuring the relative concentrations of iodine atoms in the photostationary state, through irradiation by a c.w. argon-ion laser at 4880 Å. The relative concentration has been obtained from the absorption intensity for the emission line from an iodine discharge lamp at 1830 Å. The rate constants have been given for the diffusion of iodine atoms and for the second-order recombination of iodine atoms. The values of the diffusion rate constants in various foreign gases have been compared with the calculated values. The logarithmic second-order rate constants in various gases were plotted against their ionization potentials. The plot yielded a straight line, indicating that the formation of the charge-transfer complex between iodine atoms and foreign gas molecules is important in the recombination process, as has been suggested by Porter et al.