bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Structure of Bromotrichloromethane as Determined by Gas Electron Diffraction
Authors: Konaka Shigehiro , Yamagata Kiyo , Kimura Masao 
Published: July 2006

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
A series of aryl hydrazonates has been prepared in excellent yield (&gt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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&gt;styrene&gt;α-methylstyrene&gt;cis-stilbene&gt;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

Abstract
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&lt;xTBA&lt;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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.
Wittig Reaction of 1,3-Benzodithiol-2-ylidenetriphenylphosphorane with Carbon Disulfide
Authors: Nakayama Juzo , Maruyama Sanae , Hoshino Masamatsu 
Published: July 2006

Abstract
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

Abstract
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

Abstract
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

Abstract
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

Abstract
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.