bluuebunny/crossref_metadata_2025 huggingface dataset:
Determination of the Non-stoichiometry of Zeolite A
Authors: Ohgushi Tatsuo
Published: July 2006

Zeolite A was synthesized in the sodium form with the composition Na12(AlO2·SiO2)12(NaAlO2)δ·nH2O, 0≤δ≤1. A new method was developed for the determination of the δ-value of the non-stoichiometric part in the product. It consists of repeated ion exchanges of zeolite with TINO3 (or BaCl2), and determination of the residual amount of Na+ in the zeolite as a function of the number of treatments. The Kδ/δ value was determined from a linear plot, where Kδ is a selectivity coefficient of the ion exchange reaction between Tl+ (or Ba2+) and Na+ in the non-stoichiometric part. The Kδ value was taken from the observed Kδ/δ value, the δ-value being obtained by chemical analysis. The δ-value of a sample can be determined by introducing the Kδ-value into Kδ/δ. An approximate δ-value can be estimated from a break point of the curve, log(residual amount of Na+) vs. the number of times of treatment.
The Fluidity and Electrolytic Conductivity of Alkali-metal Chloride/Poly(ethylene oxide)–H2O Systems. The Effects of the Polymer Concentration and the Temperature
Authors: Isono Toshiaki , Takahashi Katsuo , Tamamushi Reita
Published: July 2006

The fluidities of poly(ethylene oxide) (PEO)–H2O mixtures and the electrolytic conductivities of alkali-metal chlorides in the PEO–H2O mixtures were measured at different PEO compositions and temperatures (25–50 °C). The extended Walden’s rule was found to be satisfied when the fluidity and conductivity were changed by the temperature variation at a constant composition, whereas a large deviation from Walden’s rule was observed upon the isothermal variation of the PEO composition. The Arrhenius activation parameters were determined from the temperature dependence of the fluidities and conductivities, and some correlations between pairs of parameters were examined.
4-Dimethylaminopyridine N-Oxide as an Efficient Oxidizing Agent for Alkyl Halides
Authors: Mukaiyama Shigemi , Inanaga Junji , Yamaguchi Masaru
Published: July 2006

Various types of alkyl halides were converted into aldehydes or ketones in high yields with 4-dimethylaminopyridine N-oxide in the presence or absence of DBU.
Alkylation of Thioureas and Related Compounds by Use of Alcohols, Diethyl Azodicarboxylate, and Triphenylphosphine
Authors: Nagasawa Hiroshi , Mitsunobu Oyo
Published: July 2006

The alkylation of ambident nucleophiles having a thiocarbonyl group by use of alcohols, diethyl azodicarboxylate, and triphenylphosphine was studied. Selective S-alkylation took place in the cases of N-benzoyl-N′-mono- and -disubstituted thioureas, while selective N-alkylation occurred in the reaction of N-phenyl-N′,N′-diethylthiourea. 1-Methoxymethyl-2-thiouracil afforded both N-alkylated and S-alkylated products.
Stereochemical Studies of the Hydrogenation with an Asymmetrically Modified Raney Nickel Catalyst. The Hydrogenation of Acetylacetone
Authors: Tai Akira , Ito Kazuhisa , Harada Tadao
Published: July 2006

The hydrogenation of acetylacetone (I) over asymmetrically modified Raney nickel (MRNi) proceeded, step by step, as follows: acetylacetone (I)\oversetStep 1→ 4-hydroxy-2-pentanone (II) \oversetStep 2→ 2,4-pentanediol (III). It was demonstrated that the optical yield of Step 1 and the diastereomer excess of Step 2 are governed by the ratio of the stereo-differentiating reaction site to the non-stereo-differentiating reaction site on the catalyst. The stereochemistry of each step was also discussed based on the mode of the intermolecular hydrogen bondings between the substrate and tartaric acid adsorbed on the catalyst. RNi modified with a mixture of tartaric acid and NaBr (TA–NaBr–MRNi) gave the best result with respect to both Step 1 and Step 2.
Synthesis of Hypacrone
Authors: Sakan Fujio , Minami Yukio , Shirahama Haruhisa , Matsumoto Takeshi
Published: July 2006

Hypacrone, an illudoid sesquiterpene, was synthesized from 2,2-dimethyl-4-(3,3-ethano-4,4-ethylenedioxy-1-methylsulfinyl-2-oxopentyl)-1-cyclopentanone which is a key intermediate also in the synthesis of illudins.
Molecular Structure of Trimethylphosphine–Boron Tribromide as Determined by Gas Electron Diffraction
Authors: Iijima Kinya , Koshimizu Eiichi , Shibata Shuzo
Published: July 2006

The molecular structure of trimethylphosphine–boron tribromide (CH3)3P·BBr3 has been determined from gas electron-diffraction and vibrational-spectroscopic data. The molecular parameters and their uncertainties were rg(B–Br)=2.010±0.009 Å, rg(P–B)=1.946±0.029 Å, rg(C–P)=1.804±0.004 Å, rg(C–H)=1.098±0.010 Å, ∠BrBBr=111.7±0.7°, and ∠CPC=108.0±0.7°. The potential barrier around the P–B bond was also estimated to be about 10 kcal mol−1 (1 cal=4.184 J).
Computer Counting of the Number of Water Molecules in the First Layer of Crystalline Water Clathrate
Authors: Tabushi Iwao , Kiyosuke Yo-ichi , Yamamura Kazuo
Published: July 2006

Semiempirical calculation of the number of water molecules in the first layer of water clathrates in crystalline state was developed by computer aided construction of hydrogen-bonded network of water molecules. In the generalized thermodynamic considerations on four possible types of “unit clathrate,” van der Waals stabilization energy, “strain” energy of the unit clathrate, and entropy term due to the motional freedom of the guest were taken into account for the calculation of free energy change for the formation of the water clathrate. The results of calculations on 37 hydrophobic organic molecules well represented the trend of the reported experimental data of X-ray studies. The present calculation also disclosed such a large unfavorable strain energy (8.72 kcal·mol−1) of pentakaidecahedron that it counteracts the van der Waals stabilization. The result is in a good agreement with the fact that pentakaidecahedral cavity is rarely seen in the gas hydrates. Most importantly, these semiempirical calculations of the energetics of water clathrates afforded valuable new insights into water assembly and may be extended to give better understandings of structured water in biological system and of water clusters that develop around apolar solutions in water.
Determination of the Specific Heat Capacities of Aqueous Solutions of Pentose
Authors: Kawaizumi Fumio , Kushida Shigemi , Miyahara Yutaka
Published: July 2006

A laboratory-constructed isoperibol twin calorimeter of dry shield type (J. Chem. Thermodyn., 13, 89 (1981)) was used for measurements of the specific heat capacities of aqueous solutions of d-xylose, d-ribose, d-, and l-arabinose at ca. 30 °C. The partial molar heat capacity at infinite dilution, Cp.2∞ was determined. Values of Cp.2∞ obtained are: d-xylose 281±2, d-ribose 271±2, d-arabinose 278±3, and l-arabinose 270±4 J K−1 mol−1. Measurements of the heat capacity of these pentoses in the solid state, Cp.2* were carried out and the parameter ΔCp.2∞≡Cp.2∞–Cp.2* was evaluated. Values of ΔCp.2∞ are smaller than the corresponding values for hexose obtained previously. Similarly as had been the case for hexose, the additivity parameters of the group contribution on Cp.2∞ of solute estimated from the data on other nonelectrolytes were not acceptable for pentose. From this point the interactions working between solute of saccharide and the solvent water are considered to have characters largely different from those of other nonelectrolyte.
Structure and Properties of Diaquabis(methylthioacetato)cobalt(II), [Co(C3H5SO2)2(H2O)2], and Its Anhydride
Authors: Ouchi Akira , Shimoi Mamoru , Takeuchi Toshio , Saito Hideo
Published: July 2006

The crystal and molecular structure of the title complex has been determined by the X-ray diffraction method. The crystal was triclinic, space group P\bar1, a=6.750(2), b=9.214(4), c=5.206(2) Å, α=102.57(6), β=103.44(6), γ=100.70(3)°, Z=1, DX=1.702(3), Dm=1.72(3) mg m−3, μ(Mo Kα)=1.89 mm−1, and the final R value was 0.034 for 1175 reflections. The molecular arrangement has a center of symmetry and a distorted octahedron is formed around the central cobalt(II) atom; each methylthioacetato ligand forms a chelate ring by coordinating through a sulfur atom and a carbonyl oxygen atom, and two water molecules also coordinate to the central metal. Its amorphous anhydride as well as the other type anhydride, which resembles the bis(propylthioacetato)cobalt(II) hexamer in its infrared and visible spectra, is obtained by the dehydration process.
Transition-metal Complexes of Pyrrole Pigments. XXI. One-electron Oxidation of Water Mediated by a Cobalt(III)–Tetradehydrocorrin Complex
Authors: Murakami Yukito , Aoyama Yasuhiro , Tada Toshito
Published: July 2006

The cobalt(III) complex of tetradehydrocorrin (TDHC), having pKa1 6.15 and pKa2 11.50 for successive acid-dissociation of axial aqua ligands, undergoes auto-reduction to the cobalt(II) complex in aqueous carbonate solutions. Kinetic analysis of the reaction indicates the following mechanism: a one-electron transfer from the axial hydroxo ligand to the metal site, subsequent homolytic cleavage of the Co–OH bond, and finally scavenging of the resulting hydroxyl radical with the carbonate ion. At relatively low concentrations of the carbonate ion, the scavenging step is rate-determining; while at [CO32−]≥1.0×10−2 mol dm−3 for [CoIII(TDHC)] of 7.62×10−5−1.27×10−5 mol dm−3, the initial bond homolysis becomes rate-determining. Analysis of the kinetic data in reference to relevant electrode potentials indicates that the powerful oxidation ability of CoIII(TDHC) is responsible for one-electron oxidation of the hydroxo ligand. Reduction of CoIII(TDHC) also takes place in the absence of the carbonate ion, the apparent rate increasing with rise of pH in the range 11–12; deprotonation of the hydroxyl radical, which may prevent the hydroxyl radical and the cobalt(II) species from backward recombination, takes place. The one-electron oxidation of the hydroxo ligand was also significantly accelerated by addition of acetonitrile or t-butyl alcohol.
Iminodimagnesium Reagents. Condensation Reaction with Ketones. Direct Preparation of Anils and a Hydrazone of Xanthone
Authors: Okubo Masao , Hayashi Saeko , Matsunaga Mayumi , Uematsu Yumiko
Published: July 2006

The condensation reaction of ketones with iminodimagnesium reagents (RN(MgBr)2) derived from various primary amines as well as 1,1-disubstituted hydrazines was investigated. N-Arylimines and 1-methyl-1-phenylhydrazones of diaryl ketones were prepared, their yields being affected by the electronic and positional effects of substituents of reagent and substrate. Direct preparation of some anils of xanthone and its 1-methyl-1-phenylhydrazone was achieved by use of the corresponding iminodimagnesium reagents.
The Adsorption of Nucleic Acid Bases by Raney-nickel, -cobalt, and -copper
Authors: Mita Keisuke , Hotta Kazuhiko , Watanabe Shoji
Published: July 2006

The order of the relative affinity of adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U) to Raney-nickel, Raney-cobalt and Raney-copper was determined in an alkaline solution by means of a columnchromatographic method. These bases could be placed in these orders: G>A>C>U>T for Raney-nickel, G>C>A>T∼U for Raney-cobalt, and A∼G∼C>T∼U for Raney-copper. It was also found that these Raney-metals could be placed in the following order as to ability to distinguish those bases: Raney-nickel>>Raney-cobalt>Raney-copper.
Reaction of Organic Tin(II) Compound with Carbonyl Compound
Authors: Wakeshima Ikuko , Kijima Ichiro
Published: July 2006

The reactions of organic tin(II) compounds bearing Sn–OC bonds with carbonyl compounds, C6H5COR (R=C6H5CO, C6H5, and H) and p-benzoquinone, have been investigated. The tin(II) compound reacted with benzil and p-benzoquinone to yield the corresponding oxidative addition products. However, the oxidative addition reaction did not occur in benzophenone and benzaldehyde.
Proton Equilibria of 5-Dimethylamino-1-naphthalenesulfonyl Group Conjugated to Bovine Serum Albumin. II. Neighboring Effects in Urea and Guanidinium Chloride Solutions
Authors: Ikuta Nobuo , Nomura Eisaku , Koga Joichi , Kuroki Nobuhiko
Published: July 2006

Protonation to the fluorescent probe, 5-dimethylamino-1-naphthalenesulfonyl group, which had been conjugated to bovine serum albumin, was investigated in aqueous solutions of urea and guanidinium chloride. pK values not less than those of the free probe were present even in the positive range of net charge on the protein at high concentration of the denaturants. This was interpreted in terms of the electrostatic and nonpolar effects based on short-range interaction between the probe and its neighboring residues. These effects were substantiated by the reduction of the disulfide bonds in the protein and by the variation of the dielectric constant of the local environment surrounding the probe.
The Oxidation of 3,3-Diphenyl-2-propenoic Acid with Manganese(III) Acetate
Authors: Kurosawa Kazu , Tsujita Tsuyoshi
Published: July 2006

The oxidation of 3,3-diphenyl-2-propenoic acid with manganese(III) acetate in boiling acetic acid gave 3,3-diphenyl-2-propenyl acetate, 4-acetoxymethyl-5,5-diphenyltetrahydro-2-furanone, 3,3-diphenyl-2-propenal, 5,5-diphenyl-2,5-dihydro-2-furanone, 4-acetoxy-5,5-diphenyltetrahydro-2-furanone, benzophenone, and 2-oxo-5,5-diphenyltetrahydro-4-furancarboxylic acid. The reaction pathways are discussed.
The Crystal Structure of the Charge-transfer Complex of Dibenzotetrathiafulvalene-Tetracyanoquinodimethane, DBTTF–TCNQ
Authors: Kobayashi Hayao , Nakayama Jyuzo
Published: July 2006

The crystal of the charge-transfer complex of dibenzotetrathiafulvalene-7,7,8,8-tetracyanoquinodimethane, DBTTF–TCNQ, belongs to the triclinic system; a=10.309(8), b=8.281(2), c=7.727(3) Å, α=110.03(4), β=109.80(4), γ=72.05(3)°, space group P\bar1 with Z=1. The structure has been determined by the X-ray method. DBTTF and TGNQstack alternately along [011] to form mixed columns; this phenomenon is responsible for the low electrical conductivity of DBTTF–TCNQ. The intermolecular distance between DBTTF and TCNQ is 3.303 Å. The charge-transfer complexes of DBTTF with TNB, TCNE, DDQ,and fluoro-TCNQ, were examined by means of X-ray photographs. It is shown that the DDQ, complex, exhibiting a high conductivity, has segregated uniform columns of donors and acceptors, such as were not found in the other complexes.
Molecular Structure of Bromotrichloromethane as Determined by Gas Electron Diffraction
Authors: Konaka Shigehiro , Yamagata Kiyo , Kimura Masao
Published: July 2006

The molecular structure of CBrCl3 has been determined by gas electron diffraction to be as follows: rg(C–Cl)=1.7654(l7) Å, rg(C–Br)=1.944(4) Å, and ∠ClCCl=109.74(l3)°. The mean amplitudes have been fixed at the calculated values in the data analysis. The result has been compared with the structures of related halomethanes.
An Alternative Display of Potentiostatic Measurements. I. Instrumental Design and Verification of Modified Pulse Polarograph
Authors: Kato Yoshikiyo , Anzai Yoshio , Yamada Akifumi , Tanaka Nobuyuki
Published: July 2006

A modified instrument for the potentiostatic method (modified pulse polarograph) has been developed, which uses techniques of the time-to-voltage converter. The modified pulse mode and the modified differential pulse mode have been tested as tools for quantitative analysis. The determination of kinetic parameters of electrode reactions is presented, together with the characteristics of the modified pulse polarograph.
Circular Dichroism of Chromium(III) Complexes. VI. Preparation, Optical Resolution, and Circular Dichroism Spectra of (Amino acidato)bis(ethylenediamine)chromium(III) Complexes
Authors: Kaizaki Sumio , Ito Mieko
Published: July 2006

Three (amino acidato)bis(ethylenediamine)chromium(III) complexes were prepared and resolved into their optically active isomers, their absorption and circular dichroism spectra being measured in the spin-forbidden and spin-allowed d-d transition regions. The amino acids used were glycine, l-alanine, and l-phenylalanine, the latter two yielding pairs of diastereomeric, not enantiomeric, isomers in their complexes. The configurational and vicinal CD curves were obtained from the observed CD of each pair of diastereomers. The additivity of configurational and vicinal contributions to the optical activity in the whole region of the d-d transitions was substantiated. The configurational and vicinal CD peaks in the spin-forbidden band region were assigned in connection with those in the first spin-allowed band region.
Studies of the Generation of Excited Singlet Products in the Oxidation of the –CO–CH– Containing Molecules. The Chemiluminescence of Acylcarbazoles
Authors: Kamiya Isao , Sugimoto Takashi
Published: July 2006

Direct chemiluminescence emissions have been found from the air oxidation of 3-acyl-9-methyl- (1), 3,6-diacyl-9-methyl- (2), and 9-acylcarbazoles (3) due to the generation of an excited singlet state of monocarboxylate ions (from 1 and 2) and the carbazole anion (from 3). The relative intensities vs. the reaction time for the luminescent reaction of 3-isobutyryl-9-methylcarbazole could be interpreted by a reaction scheme involving consecutive reactions. Using this reaction scheme, the values of the decomposition rate of intermediates at 30, 40, and 50 °C were determined to be 0.19, 0.42, and 0.98 min−1 respectively, which were comparable to the values reported for the decomposition rates of isolated dioxetanes giving excited singlet products.
The Measurement of the Solubility of Metallic Mercury in Hydrocarbons by Means of the Cold-vapor Atomic Absorption Method
Authors: Okouchi Shoichi , Sasaki Sokichi
Published: July 2006

The metallic mercury solubility in hydrocarbons (pentane, hexane, heptane, and octane) was determined in the temperature range from 5 to 40 °C by the cold-vapor atomic absorption method. The results, for pentane at 25 °C, were found to agree well with Kuntz’s result obtained by means of the ultraviolet absorption method, while those for hexane, heptane, and octane were found to agree well with Spencer’s results, which were obtained using a radioactivetracer technique in the above temperature range. The liquid-liquid distribution constant for metallic mercury between the above hydrocarbons and water was measured at 25 °C, and in each case was found to be equal to the ratio of the independent solubility in the hydrocarbon and in water.
Electronic Spectra of Some Aromatic Free Radicals
Authors: Izumida Tatsuo , Inoue Kunihiko , Noda Shoji , Yoshida Hiroshi
Published: July 2006

Electronic spectra are reported for 1-indanyl, 1-tetralyl, and 1-indenyl radicals generated photolytically or radiolytically in rigid matrices; the former two radicals show spectral features similar to those of benzyl radical, whereas the latter radical has a different spectrum because of its non-alternant π electron system.
Studies on Biologically Active Pteridines. VII. Absolute Configuration of (−)-6-Methyltetrahydropterin Produced by Enzymic Reduction
Authors: Matsuura Sadao , Sugimoto Takashi
Published: July 2006

The C-6 configuration of (−)-6-methyltetrahydropterin, produced by enzymic reduction of the 7,8-dihydro precursor, is shown to be S by a synthesis. Condensation of 2,4-diamino-5-bromo-6-hydroxypyrimidine with (S)-1,2-propanediamine gave (S)-6-methyltetrahydropterin. Examination of CD spectra of the 6-methyltetrahydropterins from the two origins led to the above conclusion.
Preparation of Aryl Hydrazonates and 1,2-Diacylhydrazines by Phase Transfer Catalysis
Authors: Shawali Ahmad Sami , Hassaneen Hamdi Mahmoud , Pagni Richard , Sherif Mourad Sherif
Published: July 2006

A series of aryl hydrazonates has been prepared in excellent yield (>90%) by phase-transfercatalysis technique from the corresponding phenol and hydrazonoyl bromides in dichloromethane in the presence of tetrabutylammonium iodide. 1,2-Diacyl derivatives of arylhydrazines were also prepared by the same technique using carboxylic acids in place of phenols.
PTFE-bonded Raney Nickel Hydrogen Electrodes in Alkaline Fuel Cells
Authors: Kenjo Tadao
Published: July 2006

Polytetrafluoroethylene (PTFE)-bonded Raney nickel hydrogen electrodes have been prepared and their polarizations have been measured at 62 °C, using 6 M KOH (1 M=1 mol dm−3) as an electrolyte. The electrodes were reproducible in polarization characteristics from electrode to electrode. The polarization resistance was found to be 0.29 Ω cm−2 for the electrode loaded with a 48-mg cm−2 catalyst. The limiting current density was 600 mA cm−2 for the electrode loaded with a 45.4-mg cm−2 catalyst. The influences of the pressure of the press machine and of the PTFE content on the polarizations have been investigated. The polarization resistance decreases with the catalyst loading in the manner to be expected from the reaction mechanism of the gas diffusion through electrolyte film. An experimental evidence for this reaction mechanism has been obtained by measuring the polarization of an electrode of a triple-layered structure containing a silver powder layer.
Isomorphism in the High-temperature Forms of Molecular Complexes between Aromatic Hydrocarbons and Various Electron Acceptors Arising from Molecular Motion
Authors: Inabe Tamotsu , Matsunaga Yoshio , Nanba Mikiko
Published: July 2006

In addition to the six crystalline pyrene complexes reported earlier, the high-temperature forms of the following nineteen 1:1 molecular complexes have been found to be isomorphous to each other; the pyrene complexes with 1,3,5-trinitrobenzene, 2,4,6-trinitrophenol, 4-nitrophthalic anhydride, pyromellitic dianhydride, 5-nitrobenzofuroxan, 4,6-dinitrobenzofuroxan, and benzotrifuroxan, the fluoranthene complexes with 2,4-dinitrophenol, 1,3,5-trinitrobenzene, 2,4,6-trinitrochlorobenzene, 2,4,6-trinitrophenol, 2,4,6-trinitrotoluene, 4-nitrophthalic anhydride, pyromellitic dianhydride, 4,6-dinitrobenzofuroxan, and benzotrifuroxan, and the phenanthrene complexes with 1,3,5-trinitrobenzene, 2,4,6-trinitrophenol, and 4,6-dinitrobenzofuroxan. Furthermore, metastable isomorphous forms were obtained in the process of the solidification of the melt of the following three complexes: fluoranthene-5-nitrobenzofuroxan, phenanthrene-2,4,6-trinitrotoluene, and phenanthrene-4-nitrophthalic anhydride. Rather large entropies of the transitions to these unique high-temperature forms, up to 57 J mol−1 K−1, are often comparable with the entropies of melting, 46–67 J mol−1 Kr−1. The isomorphism in these twenty-eight complexes is demonstrated by essentially identical and very simple X-ray diffraction patterns and/or by the formation of continuous solid solutions between pairs of these forms. A trigonal lattice is proposed as the probable structure of these high-temperature forms. A broad-line 1H NMR study clearly showed that the unusual features of these isomorphous forms are mostly associated with the onset of a large degree of molecular motion at the transition temperatures.
Formation of H(n=4) and CH(A2Δ) by the Electron Impact Dissociation of Benzene, Pyridine, and Pyrazine
Authors: Tokue Ikuo , Ikarashi Masami
Published: July 2006

Benzene, pyridine, and pyrazine were excited by electron impact (0–70 eV) under low pressure conditions. In the wavelength region of 250–510 nm, emissions from H, CH, C2, and CN (except for benzene) fragments were observed. Formations of H(n=4) and CH(A2Δ) from benzene, pyridine, and pyrazine were investigated. The appearance potentials for the hydrogen Balmer β emission were determined to be 19.5±1.0 eV in benzene, 19.7±1.0 eV in pyridine, and 19.6±1.0 eV in pyrazine. The appearance potentials for the CH(A-X) emission were also determined to be 12.7±1.0 and 21.4±1.0 eV in benzene, 20.1±1.0 eV in pyridine, and 18.5±1.0 eV in pyrazine. No emissions from the excited parent species of pyridine and pyrazine were observed.
Formation of Electron-Donor-Acceptor Complex and 1,4-Cycloadduct of Tetracyanoethylene with Styrene and Its α- or β-Substituted Derivatives
Authors: Uosaki Yasuhiro , Nakahara Masaru , Osugi Jiro
Published: July 2006

EDA-complex formation and 1,4-cycloaddition of tetracyanoethylene (TCNE) with styrene,α-methylstyrene, 1,1 -diphenylethylene, cis-stilbene, and trans-stilbene were studied spectrophotometrically in chloroform at 25 °C. Formation constants of the EDA complexes were found to be in the order, trans-stilbene>styrene>α-methylstyrene>cis-stilbene>1,1-diphenylethylene. The difference in the formation constants was discussed in terms of both electronic and steric effects of the donors studied. α-Methylstyrene and 1,1-diphenylethylene underwent thermal cycloaddition to TCNE faster than styrene. It is suggested that some charge separation took place in the transition state. The fact that trans- and cis-stilbenes do not react with TCNE was explained in terms of the difference in stability of the 1,4-cycloadducts estimated from the 1,4-bislocalization energy obtained by Dewar’s perturbation molecular orbital method.
Determination of Local Structure and Moving Unit Formed in Binary Solution of t-Butyl Alcohol and Water
Authors: Ito Nobuyuki , Kato Tadashi , Fujiyama Tsunetake
Published: July 2006

The concentration dependences of the mutual diffusion coefficients at 24, 37, and 63 °C were observed for a binary solution of t-butyl alcohol (TBA) and water by the use of the light scattering method. The observed concentration dependences of the mutual diffusion coefficients were explained well by postulating the existence of a “moving unit”–a group of molecules which move together for a time much longer than the velocity correlation time. The structure of the moving units which are formed in the solution are (H2O)11TBA at 24 °C and (H2O)20TBA at 63 °C in the concentration range of 0<xTBA<0.1, where xTBA is the mole fraction of TBA. Taking into account the local structures, which had been determined from the concentration dependences of the mean-square concentration fluctuation values, we could conclude that water molecules form a polyhedron which encages a TBA molecule and that these cages then gather together to form an aggregate. It is essential that these polyhedra do not share their faces with each other in the aggregate. It was also concluded that the number of cages which form an aggregate increases with an increase in the temperature. This suggests the existence of a pseudo-critical temperature for this system. That is to say, the TBA–water solution can separate into two phases under high pressures, a TBA-rich phase and a water-rich phase, in the latter of which almost all the molecules form polyhedra.
The Electrical Conductivity of Graphite Filaments and Their Alkali-metal Intercalation Compounds
Authors: Sano Mizuka , Sato Naoki , Inokuchi Hiroo , Tamura Shohei
Published: July 2006

A bundle of carbon filaments, each about 20 cm in length and 7 μm in diameter, could be grown from purified graphitic material in argon plasma generated in a d.c. arc. The filaments were converted into softer filaments on heat-treatment to 3000–3400 °C. The filaments formed intercalation compounds of potassium, rubidium, and caesium. The electrical resistivities were found to be 1300, 610–660, 23–25, and 28–30 μΩ cm at 300 K for the original filament, the heat-treated filament, and the first stage golden and the second stage dark-blue intercalation compounds of the heat-treated filament, respectively.
Structural Studies of Fortimicins. IV. The Crystal Structure of Fortamine Sulfate Trihydrate and the Anion Effect on Fortamine Conformation
Authors: Hirayama Noriaki , Shirahata Kunikatsu , Ohashi Yuji , Sasada Yoshio
Published: July 2006

The molecular and crystal structure of fortamine sulfate trihydrate, C8H18N2O4·H2SO4·3H2O, was determined by X-ray analysis. The space group is P21 with a=7.2516(9), b=11.193(1), c=9.022(1) Å, β=90.55(2)°, and Z=2. The structure was solved by direct methods, and least-squares refinement using 1679 reflexions led to the final R value of 0.063. The ring conformation of fortamine sulfate is a chair form which corresponds to a chair obtained by inversion of that in the dihydrochloride. This is an extraordinary example of the cyclohexane ring inversion caused by the anion exchange in the crystal. The ring conformation of fortamines in solution and in crystal are compared and discussed.
Determination of Ultratrace Zinc by Enzymatic Activity of Carbonic Anhydrase. II. Use of Carbonate Hydro-lyase Activity
Authors: Kobayashi Kensei , Fujiwara Kitao , Haraguchi Hiroki , Fuwa Keiichiro
Published: July 2006

A method for the determination of trace zinc has been investigated using hydro-lyase activity of carbonic anhydrase. It was proved theoretically and experimentally that the activation rate of the apo-carbonic anhydrase with zinc is proportional to the amount of zinc present in the solution. Hydro-lyase activity was measured electrochemically using sodium hydrogencarbonate as a substrate. The limit of detection was 0.89 ng/ml or 40 pg of zinc, lower than that obtained by the esterase activity method. Application of the present method to the determination of zinc in real samples has been examined in order to evaluate its analytical feasibility.
The Biosynthesis of Monoterpenoids in Higher Plants. The Biosynthetic Pathway Leading to the Monoterpenoids from Amino Acids with a Carbon-skeleton Similar to Mevalonic Acid
Authors: Tange Keiji
Published: July 2006

Radioisotopically labeled l-leucine, l-valine, Dl-alanine, sodium acetate, and Dl-mevalonic acid were incorporated into linalool by the intact plant of Cinnamomum camphora Sieb. var. linalooliferum Fujita and into geraniol and citronellol by that of Pelargonium roseum Bourbon. The uptake of leucine and valine resulted in the preferential location of the radioactivity on the 3,3-dimethylallyl pyrophosphate-derived moiety of these acyclic monoterpenoids, whereas the uptake of alanine resulted in the preferential location on the isopentenyl pyrophosphate-derived moiety, much as in the cases of mevalonic acid and sodium acetate. A biosynthetic pathway leading to the monoterpenoids from the amino acids is discussed.
Dynamic NMR as a Nondestructive Method for the Determination of Rates of Dissociation. III. Ionic Dissociation of α-Chlorodibenzyl Sulfide
Authors: Shimizu Atsushi , Sakamaki Yoshitaka , Azuma Kazufumi , Kihara Hiroshi , Nakamura Nobuo , Oki Michinori
Published: July 2006

Rates of dissociation of α-chlorodibenzyl sulfide have been determined by dynamic NMR technique. Examination of the rates at various concentrations of chloroform-d solutions has confirmed that the rates are not dependent on concentration, thus establishing that the NMR measurement affords data of unimolecular dissociation. The salt effect seems to be very small since addition of tetraethylammonium bromide hardly affects the rates of dissociation. Rates of dissociation in o-dichlorobenzene are smaller than in chloroform-d. The main contribution to the decrease in rates is given by the increase in enthalpy of activation, indicating that the hydrogen-bonding ability of chloroform is favorable for ionic dissociation.
Chiroptical Properties of 10,11-Dihydro-5,10-methano-5H-dibenzo[a,d]cycloheptene Derivatives
Authors: Hagishita Sanji , Kuriyama Kaoru
Published: July 2006

The titled compounds have been prepared from (+)-(9R,10R)-dimethyl 11-oxo-9,10-dihydro-9,10-ethanoanthracene-1,5-dicarboxylate. Their absolute configurations were determined by chemical reaction, and by IR and CD spectra. Although the CD spectra of 2 and 3 (R=NH2) were expected to show an antipodal pattern from analysis of the simple coupling mechanism, they showed approximately the same magnitude of the positive Cotton effect in both regions of the 1Lb and 1La benzenoid transitions. Their CD spectra were calculated by the point-dipole exciton treatment and by the π-SCF approximation using the dipole velocity procedure with and without the charge transfer transition between the aromatic chromophores. Thus, the electric transition dipole moment should not be treated as a point dipole at any place and the rotational strength should be calculated by the dipole velocity procedure since a local magnetic transition dipole moment was produced perpendicular to the benzene ring in the region of the 1Lb transition. The charge transfer transition can not be neglected in the calculation of the MO, though it does not cause the alteration of the sequence of the coupling mode.
The Correlation between the Electron-capture Detector Response and the Chemical Structure for Polychlorinated Biphenyls
Authors: Hattori Yukikazu , Kuge Yoshio , Nakamoto Masao
Published: July 2006

The relative sensitivities of an electron-capture detector for various polychlorinated biphenyls were measured at different temperatures. Generally, the sensitivities of these compounds become larger as the number of the chloro substituent increases. The temperature dependence of the electron-capture coefficients (K) for these compounds was also determined. These results show that the electron-capture reactions of polychlorinated biphenyls containing less than four chlorine atoms proceed dissociatively, while for four chlorine atoms the reactions proceed either dissociatively or non-dissociatively. For more than five chlorine atoms, the reactions almost always proceed non-dissociatively.
The Far-infrared Absorption Intensities and the Dipole Moments of Acetone and Dimethyl Sulfoxide in Solutions
Authors: Ohkubo Yusei , Kimura Masao
Published: July 2006

The effective dipole moments of acetone and dimethyl sulfoxide in nonpolar solutions were obtained from the far-infrared absorption intensities on the basis of an extended Onsager model with an eccentric point dipole.
Excess Thermodynamic Functions of the Systems Cyclohexane+Isomeric Xylenes
Authors: Rajagopal Eyunni , Subrahmanyam Saraswatula Venkata
Published: July 2006

The excess volumes VE, excess heat capacities CPE and excess isothermal compressibilities βTE of cyclohexane+ isomeric xylenes have been determined at 25, 40, and 50 °C. The results are discussed in the light of Flory’s theory.
An Improved Oxidation Method of Pyridoxine
Authors: Iwata Masaaki
Published: July 2006

Manganese dioxide oxidation in the presence of primary amine was found to be an efficient oxidation system for pyridoxine.
Wittig Reaction of 1,3-Benzodithiol-2-ylidenetriphenylphosphorane with Carbon Disulfide
Authors: Nakayama Juzo , Maruyama Sanae , Hoshino Masamatsu
Published: July 2006

1,3-Benzodithiol-2-ylidenetriphenylphosphorane reacted with carbon disulfide to give 1,3-benzodithiole-2-thione, dibenzotetrathiafulvalene, and an unidentified crystalline red compound in addition to triphenylphosphine sulfide. The same products were also obtained by treatment of 1,3-benzodithiol-2-ylthiocarbonyl chloride with base.
A Mild and Convenient Procedure for Conversion of Aromatic Compounds into Their Iodides Using Ammonium Hexanitratocerate(IV)
Authors: Sugiyama Takashi
Published: July 2006

Polymethylbenzenes, polymethoxybenzenes, and naphthalene are iodinated with tetrabutylammonium iodide, alkali metal iodides, or molecular iodine in the presence of ammonium hexanitratocerate(IV). Ammonium hexanitratocerate(IV) behaves as a catalyst in the latter system, whereas it is a reagent in the fomer two.
Possibility of the Intramolecularity of Triazene Rearrangement
Authors: Ogata Yoshiro , Nakagawa Yoshiaki , Inaishi Morio
Published: July 2006

The mechanism for the ortho-rearrangement of diaryltriazenes still remains equivocal. An interesting result suggesting an intramolecular nature of the triazene rearrangement was obtained on the basis of the effect of concentration of added N,N-dimethylaniline in the ortho-rearrangement of 1,3-bis(4-methylphenyl)triazene (1). The ortho/para ratio for the rearrangement of 1,3-diphenyltriazene (4) tends to increase with an increase of the viscosity. The results are discussed on the basis of increasing nucleophilicity of free amine by H-bonding with dimethylaniline and favoring ortho-migration with viscosity, respectively.
On the Continuous Slowing Down Approximation for the Degradation Spectra of Secondary Electrons
Authors: Kowari Ken-ichi , Sato Shin
Published: July 2006

The degradation spectra of secondary electrons produced in helium irradiated with high energy electrons have been calculated by two methods. In the first method, the direct integration of the basic formula was carried out and in the second one, the continuous-slowing-down-approximation (CSDA) was used. When the energy of incident electrons is 1 keV (1 eV=9.648×104 J/mol), the second method gave a G-value of ionization, 2.17, while the first method gave 2.29. With the decrease in the energy of incident electrons, the CSDA was found to become less reliable. With the incident electrons of 100 eV, the error in the G-value of ionization exceeded 15%. The implication of these calculations to the theoretical treatment of the initial process of radiation chemistry is discussed. As an example, the spatial distribution of ion-pairs in γ-irradiated water has been recalculated.
Preparation and Analytical Evaluation of Liquid Membrane Electrodes Based on Solid-solvents
Authors: Hara Hirokazu , Okazaki Satoshi , Fujinaga Taitiro
Published: July 2006

A new type of liquid membrane electrode has been developed in which organic compounds solidified at room temperature were used as solvents of an ion-sensing membrane. The electrode performance of a p-toluenesulfonate ion-sensitive electrode was examined and compared with that of a corresponding liquid membrane electrode, no remarkable difference being observed in sensitivity and response time. However, a distinct difference in selectivity was observed between the 1-octadecanol (solid) and 1-decanol (liquid) membranes. The difference was interpreted on the basis of the solvation energy of interfering anions. The effects of ion-pair concentration, membrane thickness, and pH on the electrode potentials of the 1-octadecanol membrane were investigated in comparison to those of the 1-decanol membrane. The electrodes responsive to various anions such as iodide, nitrate, bromide, and chloride were prepared with an 1-octadecanol membrane.
The Determination of Antimony in Water by Atomic-absorption Spectrophotometry Following Flotation Separation
Authors: Nakashima Susumu
Published: July 2006

A flotation method which utilizes an iron(III) hydroxide–surfactant–air system at pH 4 is described for the separation of sub-microgram levels of antimony(III,V) in water. The antimony content is determined by the generation of stibine, followed by atomic-absorption spectrophotometry with a long absorption cell (60 cm×1.2 cm i.d.).
Circular Dichroism Spectra and Absolute Configurations of cis,cis,cis-(C,N,O)-Dicyanobis(glycinato)cobaltate(III) and Dicyanobis-(β-alaninato)cobaltate(III) Complexes
Authors: Fujinami Shuhei , Shibata Muraji
Published: July 2006

The [Co(CN)2(NO)2]−-type complexes (NO: gly− and β-ala−), which have cis,cis,cis geometry with respect to the donor atoms C, N, and O, have been prepared by a new method, and resolved into their optical antipodes. The CD spectra of the resolved complexes have been measured, and compared with that of (−)589[Co(CN)2(ox)(en)]− complex which has the same chromophore with the bis(glycinato) complex. It is found that the optical activity of the cis,cis,cis-[Co(C)2(N)2(O)2]−-type complex mainly arises from the arrangement of the donor atoms; the non-ligating atoms of NO ligand make minor contribution to the optical activity.
Solvent Extraction of Iron(III) in Concentrated Nitric Acid with Several β-Diketones
Authors: Sekine Tatsuya , Komatsu Y\={u} , Inaba Kazuho
Published: July 2006

The solvent extraction of iron(III) in nitric acid (1 to 13.2 mol dm−3) with seven β-diketones into carbon tetrachloride was studied. The extraction curve has a pronounced minimum at from 6 to 7 mol dm−3 acid, and the extracted iron(III) species were assumed to be represented by FeAa(NO3)3−a(HA)n (where a and n are from 0 to 3).
A Facile Reduction of Copper(II) Leading to Formation of Stable Copper(I) Complexes. Redox Properties of Four- and Five-coordinate Copper Complexes
Authors: Sakurai Takeshi , Kimura Masazo , Nakahara Akitsugu
Published: July 2006

Schiff bases derived from 2-pyridinecarbaldehyde and 1,6-hexanediamine or bis(2-aminoethyl) disulfide gave stable Cu(I) complexes instead of Cu(II) complexes by reactions with copper(II) per chlorate. The facile reduction of copper(II) has been discussed on the basis of systematic comparisons of redox and ESR properties of about 20 complexes of similar structures.
The Reaction of cis-1,2-Dichloroethylene with Borane in Tetrahydrofuran. The Supply of Monochloroborane in a Tetrahydrofuran Solution
Authors: Arase Akira , Hoshi Masayuki , Masuda Yuzuru
Published: July 2006

In the reaction of cis-1,2-dichloroethylene with borane in THF at 20 °C for 2 h, about 94% of borane was converted to monochloroborane. The resulting solution was stable at 0 °C for several hours.
Photochemical Reactions of Azidotriazines with Aromatic Substrates
Authors: Tamura Shigeru , Imaizumi Hisao , Hashida Yoji , Matsui Kohji
Published: July 2006

Triazinylnitrene generated photochemically from 2-azido-4,6-dimethoxy-1,3,5-triazine adds to the aromatic ring of alkylbenzenes and halobenzenes to give N-triazinylazepines.
X-Ray Crystallographic Studies on the Structure of Alnuserrudiolone Isolated from the Male Flowers of Alnus serrulatoides
Authors: Hirata Toshifumi , Aoki Tadashi , Suga Takayuki
Published: July 2006

The structure of alnuserrudiolone was corroborated to be (12R,20S)-12,20-dihydroxy-24-methylenedammaran-3-one by the X-ray crystallography together with the 13C NMR and the high resolution mass spectral measurements.
Synthesis and Properties of O6-Substituted Guanosine Derivatives
Authors: Daskalov Hristo Petrov , Sekine Mitsuo , Hata Tsujiaki
Published: July 2006

Reactions of 2′,3′,5′-tri-O-acetyl-N2-protected or unprotected guanosine derivatives with phosphoryl, phosphinothioyl, arylsulfonyl, and silyl halides in dichloromethane gave the corresponding O6-substituted guanosine derivatives in good yields. In these reactions, 4-(dimethylamino)pyridine (DMAP) was found to be very effective catalyst. The physical data of these products and their stabilities under acidic and basic conditions were described in detail. Selective detritylation of O6-arylsulfonyl-N2-tritylguanosine derivatives was accomplished by treatment with 80% acetic acid. It was found that O6-dibutylphosphinothioyl derivatives were relatively stable under conditions where acetyl group was predominantly removed.
Crosslinked Polyvinylpyridine Hydrochloride as a Mild Polymeric Catalyst for Acetalization of Carbonyl Compounds and Esterifieation of Carboxylic Acids
Authors: Yoshida Jun-ichi , Hashimoto Jiro , Kawabata Nariyoshi
Published: July 2006

Crosslinked poly(4-vinylpyridine) hydrochloride was found to be an effective catalyst for acetalization of carbonyl compounds and esterifieation of carboxylic acids. The polymeric catalyst was inert to some acid sensitive functional groups which cannot tolerate under the influence of a strong acid cation exchange resin.
Preparations and Properties of Optically Active (Alkyl)bis(dimethylglyoximato)cobalt(III) Complexes
Authors: Ohgo Yoshiaki , Takeuchi Seiji , Natori Yukikazu , Yoshimura Juji , Ohashi Yuji , Sasada Yoshio
Published: July 2006

Optically active alkyl cobalt complexes, CH3CHXCo(Hdmg)2·Base [X=COOCH3 or CN; Base=(R)- or (S)-1-phenylethylamine, H2O, pyridine, or (1R,2S)-1,2-diphenyl-2-aminoethanol; Hdmg=dimethylglyoximate(1-)], have been prepared, and their spectroscopic and chiroptical data are given. The rotational contribution of the chiral alkyl moiety was shown to be considerably greater than that of the chiral amine moiety. This suggests that the rotational sign (in the longer-wave length region of about 546 to 589 nm) may be useful for deducing the chirality of the alkyl moiety.
The Synthesis of Thermally Stable Oils by the Benzylation of Biphenyl with Benzyl Chloride Catalyzed by Iron(III) Oxide
Authors: Hino Makoto , Arata Kazushi
Published: July 2006

The benzylation of biphenyl with various amounts of benzyl chloride was performed at 80 °C or at room temperature in the presence of iron(III) oxide prepared by calcining, at 300 °C, iron(III) hydroxide which has been precipitated by hydrolyzing FeCl3 with ammonia. The products with various viscosities were thermally stable up to 200–300 °C, and no chlorine was detected in the products.
The Effect of γ-Irradiation on the Biodegradability of Landfill Leachate
Authors: Sawai Takeshi , Sawai Teruko , Yamazaki Masao
Published: July 2006

A preliminary examination of the enhancement of biodegradability for landfill leachate, humic acid, and fulvic acid solutions, and aqueous solutions of polyethylene glycol-6000 by irradiation by 60Co γ-rays under aeration was performed. In all cases, the BOD5/TOC and BOD5/COD ratios increased with the dose. This suggests that the γ-irradiation modified these refractory materials to more biodegradable compounds.
Corrosion Inhibition and Adsorption Behavior of Some Thioamides on Mild Steel in Sulfuric Acid
Authors: Ateya Badr G , El-Anadouli B E , El-Nizamy F M A
Published: July 2006

The objective of this work was to evalulate the effect of changing functional and structural groups on the protection efficiency imparted by the various inhibitor molecules. It was found that the molecules which include a thiocarbonyl group e.g. thiourea (TU), thioacetamide (TA), and thiosemicarbazide (TSC) exhibited much higher protection efficiencies than the corresponding compounds which do not e.g. semicarbazide, guanidine, and aminoguanidine. Furthermore, it made only little difference whether the thiocarbonyl group was attached to two amino groups as in thiourea, an amino and a methyl group as in thioacetamide or an amino and a methyl group as in thioacetamide above certain concentrations both TU and TA lose their efficiency and eventually become corrosion promotors. The adsorption behavior of TU and TA was quist complicated whereas that of TSC points towards complete coverage at high concentrations. The differences in behaviour between TSC, TU, and TA have been explained on the basis of delocalization or resonance stabilization energy.
Preparation and Ligand Field Absorption Spectra of [CrF2(O–O)2]3− and [CrF2(O–O)(en)]− Type Complexes
Authors: Kaizaki Sumio , Akaho Mieko , Morita Yasuyo , Uno Kuniko
Published: July 2006

Two geometrical isomeric pairs of [CrF2(O–O)2]3− and either one of two possible geometrical isomers of [CrF2-(O–O)(en)]−, where O–O denotes oxalate and malonate anions, were newly prepared and characterized by means of the spectral and chromatographic elution behaviors. It was found that [CrF2(ox)(en)]− and [CrF2(mal)(en)]− obtained take cis and trans forms, respectively. The ligand field absorption spectra of the present complexes were compared with one another, and with those of the corresponding aqua complexes of the same type. On the basis of the analyses of the absorption spectra in terms of the angular overlap model, the AOM parameters (eσ and ex) for the ligands concerned were estimated, and their transferability assumption and the anisotropic π interactions of Cr–O bonding with respect to the chelate plane of the dicarboxylate ligands were discussed.
Iron Catalyst Local Concentration Fluctuations Found in Dissipative Reactions by X-Ray Microanalysis
Authors: Keszthelyi Csaba P , Soós József , Janossy András G S , Vovács Kristóf
Published: July 2006

The present work provides the first application of the powerful X-ray microanalysis technique in the study of “Zhabotinskii-type” oscillatory reactions. The modified HNO3: KBrO3: [Fe(phen)a]2+: malonic acid system is quantitatively described. Systematic variation, spatially correlated with the dissipative structures, was found in the Fe concentration.
Friedel-Crafts Acylation with 2-Methyl- or 2-Benzylbutanedioic Anhydride
Authors: Hashimoto Iwao
Published: July 2006

The AlCl3-catalyzed acylation of benzene with 2-methylbutanedioic anhydride afforded a mixture of 3-benzoyl-2-methylpropanoic acid and 3-benzoylbutanoic acid. The intramolecular acylation of 2-benzylbutanedioic anhydride in the presence of AlCl3 gave a mixture of 4-oxo-1,2,3,4-tetrahydro-2-naphthoic acid and 3-oxo-2-indanacetic acid. The results were discussed in terms of the solvent effect on the acylations.