bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Structure of Cellulose Produced by Acetobacter xylinum in the Presence of a Fluorescent Brightener. The Influence of Concentration of a Brightener in the Medium on the Structure of Cellulose
Authors: Kai Akira , Kitamura Hitoshi 
Published: July 2006

Abstract
The influence of the concentration of a brightener on the structure of cellulose from an Acetobacter culture in the presence of a fluorescent brightener was examined. At a brightener concentration above 0.05 wt%, the X-ray diffraction diagram of cellulose from an incubated medium was observed. Except for the intensity of the diffraction corresponding to the (020) plane of cellulose I, the intensity of diffraction of the (110) plane became very weak and diffraction of the (1\bar10) plane disappeared. A new diffraction, not corresponding to cellulose I or II, occurred inside. The position of each diffraction pattern was constant and independent of the concentration of the brightener. As the brightener concentration of the medium became lower, in the X-ray diagram of the dyed cellulose that was produced, the diffraction intensity of both the (1\bar10) and (110) planes of cellulose I increased, and a new diffraction pattern gradually disappeared. In the case of an extraction of dyed cellulose from an incubated medium with a brightener (above 0.05 wt%), the same result was obtained. The above results suggest that the monomolecular layer of a brightener is included between the (1\bar10) planes of the produced cellulose.
Reactions of NH Radicals. V. Photolysis of HN3 in the Presence of C3H8 at 313 nm
Authors: Kodama Sukeya 
Published: July 2006

Abstract
The photolysis of HN3 vapor in the presence of C3H8 was studied at 313 nm and 30°C. The main products were N2, H2, CH4, C2H6, C3H6, NH4N3, CH3NH2·HN3, C2H5NH2·HN3, and n- and i-C3H7NH2·HN3. The quantum yields of these products were measured as a function of the pressure of HN3 or C3H8. The following mechanisms for the main reactions was proposed: HN3+hν(313 nm)→N2+NH(a1Δ); NH(a1Δ)+HN3→2N2+2H, NH2+N3, and N2+N2H2* (2); NH(a1Δ)+C3H8→C3H7NH2*(n- and i-propylamine) (3); NH(a1Δ)+C3H8→NH (X3Σ−)+C3H8 (4); C3H7NH2*→CH3+C2H4NH2 (5); CH4+C2H4NH (6), C2H4+CH3NH2 (7), C2H5+CH2NH2 (8), C2H6+CH2NH (9), H2+C3H6NH (10), and NH3+C3H6 (11); C3H7NH2*+HN3→C3H7NH2+HN3 (12); C3H7NH2*+ C3H8→C3H7NH2+C3H8 (13). The rate constant ratios are: k3⁄k2=1.28; k4⁄k2=0.262; k6⁄k5=0.109; k7⁄k5=0.050; k8⁄k5=1.39; k9⁄k5=0.040; k10⁄k5=1.20; k11⁄k5=4.72; k12⁄k5=666 dm3 mol−1; k13⁄k5=860 dm3 mol−1. The formation ratio of n-C3H7NH2/i-C3H7NH2 was 1.55, regardless of the total pressure. The half-life of 1.78×10−10 s for C3H7NH2* was obtained by using the collision theory. The relative and absolute rate constants were compared for the reactions of NH(a1Δ) with CH4, C2H6, and C3H8; it was found that the relative yield for the insertion of NH(a1Δ) into a C–H bond increases with a decrease in the C–H bond dissociation energy.
Mechanism of Resonant Two-photon Transitions via Repulsive Intermediate States. Experimental and Theoretical Studies on I2 Vapor
Authors: Shiraishi Jun , Fujimura Yuichi , Nakajima Takeshi , Kawasaki Masahiro , Kasatani Kazuo , Sato Hiroyasu , Tanaka Ikuzo 
Published: July 2006

Abstract
Mechanisms of resonant two-photon transitions via repulsive intermediate states are experimentally and theoretically studied. Polarization ratios, Ω=σ∞⁄σ↑↑ (where σ∞ and σ↑↑ are the cross section of the two-photon transitions obtained by the circularly polarized light and that by the linearly polarized light, respectively) of the two-photon excitation of iodine vapor have been measured in the wavelength range of 420–510 nm. An expression for the polarization ratio for the two-photon absorption in which both simultaneous and sequential processes take place has been presented. The polarization ratios calculated by using the δ-function approximation for the repulsive intermediate states as a function of the laser frequency for the iodine molecule system explain qualitatively the experimental result. This indicates that both the simultaneous and the sequential process take place in the frequency region measured.
Motion of CF3 Groups and Phase Transition in [Cu4(CF3COO)4]·2C6H6 as Studied by 1H and 19F NMR Techniques
Authors: Kubo Atsushi , Ikeda Ryuichi , Sampedro Jose Antofnio , Inoue Motomichi , Nakamura Daiyu 
Published: July 2006

Abstract
The temperature variation of 1H and 19F nuclear spin-lattice relaxation times T1 in [Cu4(CF3COO)4]·2C6H6 was observed at different resonance frequencies. From the NMR experiments, it was found that this complex undergoes a first order phase transition at 130 K, which was confirmed by DTA measurements. In the room-temperature phase, 1H gave normal exponential magnetization recovery curves and logT1 linearly decreased with increasing 103T−1 whereas 19F gave nonexponential magnetization recovery curves, from which long- and short-T1 components could be derived. This indicates that the C3 reorientation of CF3 groups about their respective symmetry axis is responsible for 19F T1 and for 1H T1 as well through 1H-19F cross relaxation. This was confirmed from the coincidence of the logT1 vs. 103T−1 curve of the long component and that of 1H T1. A very small activation energy of 5.5 kJ mol−1 was obtained for the CF3 reorientation. For the low-temperature phase, both 1H and 19F yielded nonexponential magnetization decay curves.
ZnII-bearing Green Rust II and Its Spontaneous Transformation into ZnII-bearing Ferrite in Aqueous Solution
Authors: Tamaura Yutaka 
Published: July 2006

Abstract
When solutions containing FeII, ZnII, and SO42− ions were oxidized by a mixed gas of air and nitrogen at pH 6.7 (25 °C), a ZnII-bearing green rust II (GR-II), which is a uniform crystalline precipitate with a definite chemical composition, was formed. The mol ratio of ZnII/FeIIin the ZnII-bearing GR-II increased linearly with an increase in the ZnII/FeII mol ratio in the reaction solution. The distribution coeffient of ZnII between the solid (ZnII-bearing GR-II) and the solution phase is 3.3 times higher than that of FeII. The ZnII-bearing GR-II was spontaneously transformed into ZnII-bearing ferrite. In this reaction, Zn2+ ions in the ZnII-bearing GR-II are preferentially incorporated into the ferrites.
Spectrophotometric and Polarimetric Investigations on Complex Formation between Copper(II) and Cyclodextrins in an Alkaline Solution
Authors: Matsui Yoshihisa , Kinugawa Kohji 
Published: July 2006

Abstract
Copper(II) forms a 1 : 1 complex (CuCD), as well as a 2: 1 complex (Cu2CD), with cyclodextrin (CD) in an alkaline solution. An equilibrium constant (Kdsp) for the disproportionation reaction of Cuα-CD to Cu2α-CD and α-CD was determined by spectrophotometry and polarimetry to be ca. 17 in 1.0 mol dm3 NaOH at 25 °C. The Kdsp value gradually decreased with increasing NaOH concentration. A ligand-exchange reaction of CU2CD with ethylenediaminetetraacetic acid (EDTA) to give Cu(edta)2− and CD was also examined by means of spectrophotometry and polarimetry. The equilibrium constants (Klex) for the ligand-exchange reaction was evaluated to be ca. 2.1 for an α-CD system and ca. 1.2 for a β-CD system in 1.0 mol dm−3 NaOH at 25 °C. The Klex value decreased rapidly with increasing NaOH concentration. The role of OH− in the complexation of Cu(II) with CD is discussed on the basis of these results.
ESR Studies on Salicylaldehyde Schiff Base Complexes of Copper(II). II. Bis(N-cyclohexyl- and N-cycloheptyl-salicylideneaminato)copper(II) Complexes and Their Derivatives in Solutions
Authors: Yokoi Hiroshi , Takeuchi Akira , Yamada Shoichiro 
Published: July 2006

Abstract
Ten of the title complexes in frozen toluene solutions and occasionally in other solutions have been studied by the ESR method. Most of the complexes showed both monomer and dimer ESR spectra simultaneously, and the equilibrium constant for 2 monomer\leftrightarrowsdimer has been determined by analyzing the concentration dependence of the intensity ratios of dimer and monomer ESR signals. The results indicate that the equilibrium constants of the complexes are dependent in a marked but subtle way, not upon the bulkiness of N-substituents, but upon both kind and position of the substituents introduced into the ligand benzene rings, and that the equilibrium constants are solvent-dependent. All the observed dimer ESR spectra were similar to each other, and computer simulation analysis of the spectra has revealed that the dimers formed in toluene have the same structures as that in green crystals of bis(N-cyclohexylsalicylideneaminato)copper(II). On the other hand, monomers of the title complexes have been found to show various degrees of tetrahedral distortion in the coordination geometry.
Interactions of Calcium Ions with Carbohydrates. The Crystal Structure of Calcium d-Glycero-d-gulo-heptonate Tetrahydrate
Authors: Taga Tooru , Kaji Taneno , Osaki Kenji 
Published: July 2006

Abstract
The crystal structure of the calcium salt of d-glycero-d-gulo-heptonic acid has been determined by the X-ray method. The crystal is monoclinic of space group P21 with unit-cell dimensions of a=10.064(1), b=10.540(2), c=11.340(2) Å, and β=108.92(1)°. The intensity data for 1754 unique reflections were measured with an automatic diffractometer. A trial structure, obtained by the direct method, was refined by the full-matrix least-squares method to R=0.030. The two independent heptonate anions have different conformations, and they chelate a calcium ion in different ways. The calcium ion is surrounded by eight oxygen atoms in a deformed dodecahedral form, the Ca···O distances ranging from 2.40 Å to 2.48 Å. The distortion of the moleular strcuture of the heptonate anions due to the calcium chelation was discussed in relation to the calcium-binding sites on a linear carbohydrate chain.
A New Aspect on the Origin of an Anomalous Substituent Effect on the Azomethine Proton Chemical Shifts in 4-Substituted N-Benzylideneanilines
Authors: Akaba Ryoichi , Sakuragi Hirochika , Tokumaru Katsumi 
Published: July 2006

Abstract
Carbon-13 chemical shifts, azomethine proton chemical shifts, and azomethine carbon–hydrogen coupling constants have been determined for N-benzylideneaniline and its several derivatives bearing o-methyl and/or p-nitro groups on the aromatic ring on the nitrogen atom (ring A). The anomalous upfield shift of the azomethine proton caused by introduction of a 4-nitro group on the ring A can be attributed to the increase in the twist angle θN of the ring A from the molecular plane containing the C=N bond.
Near-infrared Photocurrent of a Zinc Oxide Electrode Covered with Silver Atoms
Authors: Tanemura Hatsumi , Yonezawa Yoshiro , Hada Hiroshi 
Published: July 2006

Abstract
A near-infrared photocurrent has been observed in a sintered ZnO electrode whose surface was covered with Ag atoms. The photocurrent became more evident when silver deposition was carried out with a relatively large charging current. The importance of H+ reduction which competed with silver reduction is pointed out.
Equilibrium Solubilities of Benzene, Toluene, Ethylbenzene, and Propylbenzene in Silver Nitrate Solutions
Authors: Sanemasa Isao , Arakawa Seiji , Piao Cheng Yun , Deguchi Toshio 
Published: July 2006

Abstract
By making use of the solute vapor, the equilibrium solubilities of benzene and three alkylbenzenes in AgNO3 solutions have been measured. The complex formation constants of silver ions are estimated for each solute, and the results are compared with literature values.
Stereoisomers of the Bis(1,10-phenanthroline){(1R,2R)-1,2-cyclohexanediamine}cobalt(III) Complex
Authors: Tatehata Akira , Natsume Shigeru 
Published: July 2006

Abstract
The diastereomers of [Co(R-chxn)(phen)2]3+ (R-chxn=(−)589-(1R,2R)-1,2-cyclohexanediamine, phen=1,10-phenanthroline) were prepared and characterized by absorption, circular dichroism, and 1H NMR spectra. The preference of Δ-isomer in the complex formation was observed and the degree of the stereoselectivity was greater than that of the corresponding [Co(R-pn)(phen)2]3+ (pn= 1,2-propanediamine).
CD Spectra of 2,4-Dinitrophenyl Derivatives of α-Amino Acids Having Polynuclear Aromatic Group in the Side Chain. Absolute Configuration of 3-(9-Anthryl)alanine
Authors: Kawai Masao , Matsuura Taketoshi , Butsugan Yasuo , Egusa Syun , Sisido Masahiko , Imanishi Yukio 
Published: July 2006

Abstract
CD spectra of 2,4-dinitrophenyl (Dnp) derivatives of α-amino acids having polynuclear aromatic group in the side chain with l- and d-configuration showed negative and positive Cotton effect, respectively, around 400 nm in consistent with previously proposed Dnp-aromatic rule. Application of the rule revealed d-configuration of levorotatory 3-(9-anthryl)alanine, which was further confirmed by chiroptical comparison of the 2,4-dinitrophenyl derivative and its p-methoxyanilide.
Resolution of Alcohols as Esters by HPLC on (+)-Poly(triphenylmethyl methacrylate)
Authors: Okamoto Yoshio , Honda Shiro , Hatada Koichi , Yuki Heimei 
Published: July 2006

Abstract
Various secondary alcohols were resolved as benzoates or 3,5-dichlorobenzoates by high-performance liquid chromatography on optically active (+)-poly(triphenylmethyl methacrylate). Almost completely resolved alcohols include 2-butanol, 2-pentanol, 2-octanol, 3-octanol, 1-phenylethanol, cis-2-methylcyclohexanol, trans- and cis-3-methyl-cyclohexanol, and tetrahydrofurfuryl alcohol.
Kinetic Study of the Decay of Chlorine Dioxide in Supercooled and Glassy Organic Solvents
Authors: Ohta Nobuaki , Kuwata Keiji 
Published: July 2006

Abstract
Chlorine dioxide (ClO2), which is a stable free radical, decayed in supercooled and glassy liquid 3-methylhexane (3MHX) and 3-methylpentane near their glass transition temperatures (Tg’s). The decay of ClO2, however, was not observed in toluene or 2-methyl-1-propanol. The kinetic analysis of the decay of ClO2 in 3MHX is reasonably explained by its diffusional motion and dimer formation. The diffusion constants of ClO2 in 3MHX at temperatures around Tg were estimated in the analysis.
Collisional Deactivation of N(22P) Atoms by Simple Molecules
Authors: Umemoto Hironobu , Sugiyama Koichiro , Tsunashima Shigeru , Sato Shin 
Published: July 2006

Abstract
Cross sections for the quenching of N(22P) by a variety of simple organic and inorganic compounds have been determined by using a pulse radiolysis-optical absorption technique. It was found that N(22P) is less reactive than N(22D) in every case, despite its higher energy. The quenching cross sections for unsaturated hydrocarbons were found to be about one tenth of that for gas kinetic collisions, while those for saturated hydrocarbons and most inorganic substances were much smaller. The quenching cross sections for alkane hydrocarbons increase with the number of C–H bonds, and show a minor dependence on C–H bond strengths.
Synthesis of 5-O- and 6-O-Methyldihydrostreptomycin
Authors: Kishi Teruo , Tsuchiya Tsutomu , Koga Naokazu , Kobayashi Yoshihiko , Umezawa Sumio 
Published: July 2006

Abstract
5-O- and 6-O-Methyldihydrostreptomycin have been prepared from dihydrostreptomycin by a sequence of reactions involving methylation of a selectively protected derivative (4) with diazomethane in the presence of tin(II) chloride. The structures of the final products were confirmed by their 13C-NMR spectra and the TACu method.
Stereochemical Study on 1,3-Dipolar Cycloaddition Reactions of Heteroaromatic N-Ylides with Symmetrically Substituted cis and trans Olefins
Authors: Tsuge Otohiko , Kanemasa Shuji , Takenaka Shigeori 
Published: July 2006

Abstract
Stereochemistry of the cycloadditions of twenty-four heteroaromatic N-ylides with several symmetrically substituted cis and trans olefins has been investigated. Cyclic and acyclic cis olefins cycloadd to the and form of the ylides in a highly endo-selective manner giving almost quantitative yields of stereospecific endo 3+2 cycloadducts. N-Ylides stabilized with a substituent of carbonyl type react with trans olefins to form mostly two stereoisomeric 3+2 cycloadducts to the anti form of the ylides. In most cases, they undergo the stereospecific interconversion through a retro cycloaddition process, the isomer ratios and the easiness of transformation depending upon the nature and size of substituents on the five-membered ring which has been built up in the cycloaddition step. On the other hand, N-ylides stabilized with a substituent of noncarbonyl type react with trans olefins to give stereospecific and stereoselective 3+2 cycloadducts as single isomers which are assigned as the cycloadducts to the syn form of the ylides.
Preparation and Characterization of [Fe4S4(SFc)4]2− and [Mo2Fe6S8X3(SFc)6]3− (Fc=C5F4FeC5H5, X=EtS and MeO), and Their Catalytic Behaviors toward C2H2 Reduction
Authors: Tanaka Koji , Nakamoto Masami , Tashiro Yutaka , Tanaka Toshio 
Published: July 2006

Abstract
Iron–sulfur and molybdenum–iron–sulfur clusters with ferrocenethiolate, [Fe4S4(SFc)4]−2 and [Mo2Fe6S8X3(SFc)6]3− (Fc=C5H4FeC5H5, X=EtS and MeO), have been prepared as tetraalkylammonium salts. The reduction potentials of these clusters are more negative than those of the corresponding clusters with benzenethiolate suggesting that the ferrocencethiolate ligand has an electron donor ability stronger than the benzenethiolate ligand. Electronic absorption spectra reveal that the ferrocenethiolate ligand dissociates from the cluster anions in the electrochemically reduced states. The clusters can catalyze the reduction of C2H2 in water at pH 7.0 under the controlled potential electrolysis conditions. The rate of the reduction and the selectivity for the C2H4 formation are largely dependent on the clusters; the iron-sulfur cluster shows a higher activity than the molybdenum-iron clusters in the C2H2 reduction.
Activity and Selectivity Regulation of Synthesis Gas Reaction over Supported Ruthenium Catalysts
Authors: Fujimoto Kaoru , Nobusawa Tatsuya , Fukushima Takakazu , Tominaga Hiro-o 
Published: July 2006

Abstract
The catalytic activities of supported ruthenium for synthesis-gas conversion to hydrocarbons was found to be in the following order:
TiO2&gt;Nb2O3&gt;ZrO2&gt;SiO2&gt;Ta2O5&gt;Al2O3&gt;V2O5&gt;Mo3&gt;WO3&gt;MnO2&gt;ZnO
Turnover frequencies of the supported ruthenium increased with decrease in dispersion of the metal particles for every carrier material. Even the activities per unit weight of metals were higher for low-dispersion ruthenium on Al2O3, TiO2, and ZrO2. The chain-growth probability of a hydrocarbon product, which is characterized by the Schulz-Flory distribution, increased markedly with decrease in the metal dispersion irrespective of the carrier material. The catalytic activity of ruthenium particles with a dispersion level of 0.7 or higher reached a ceiling level at about 0.5 MPa, whereas that of low dispersed ruthenium increased almost linearly with an increase in reaction pressure (up to at least 2.0 MPa).
Use of Propagators in the Hückel Model. VII. Thermochemical and Photochemical Rearrangement in Cycloheptatriene, Tropone, and Related Compounds
Authors: Yamamoto Masaaki , Nishikawa Kiyoshi , Aono Shigeyuki 
Published: July 2006

Abstract
Hückel propagator theory has been applied to the analysis of photochemical and thermochemical rearrangement reactions, such as [1,3] sigmatropy, valence isomerization of norcaradiene, Cope rearrangement et al. In treatments employing the frontier orbital theory, the molecule is sometimes separated into two parts, and the orbital interaction between specified orbitals of two fragments is taken into account. In the propagator theory, the molecule is always considered as a whole, assuming a resonable transition state. In this transition state, the bond order between sites responsible for the reactions under consideration is estimated, and then the perturbing interaction between these sites is introduced. Then we can evaluate the extra energy to determine whether the reaction occures or not.
Ultralow Interfacial Tension in the Vicinity of the Upper Critical Solution Temperature of the Mixture of Water and Isobutyric Acid
Authors: Aratono Makoto , Motomura Kinsi 
Published: July 2006

Abstract
The ultralow interfacial tension of the binary liquid mixture of water and isobutyric acid has been measured as a function of temperature under atmospheric pressure in the vicinity of the upper critical solution temperature. It has been observed that the interfacial tension decreases monotonously as the temperature increases and is reduced to zero at the critical solution temperature. The results have been analyzed on the basis of the thermodynamics of interfaces. It has been found that the formation of interface is accompanied by increases in entropy and energy, which vanish at the critical solution temperature. This behavior has been considered in terms of the partial molar thermodynamic quantities of components. The brief discussion of the critical exponent has been also given for the present system.
Effect of Inner-shell Excitations on the W-Value of Propane
Authors: Suzuki Isao H , Saito Norio 
Published: July 2006

Abstract
The dependence of the propane W-value on photon energy has been precisely measured near innershell excited states using monochromatized synchrotron radiation. The W-value showed an oscillatory variation in this energy region. A model has been proposed in which inner-shell excitation is assumed to give rise to a change in the energy of the electron ejected from the molecule having absorbed a photon. It has been found that the model can reproduce the oscillatory variation feature of the W-value. A postcollision interaction is suggested to take place just above the C–K edge of propane.
A High-resolution 13C NMR Study of Some Ethylene Oxide Oligomers, Cryptands and Crown Ethers Complexed with a Variety of Metal Ions in the Solid State. Conformational Change of Ligand Molecules as Viewed from the Conformation-dependent Displacements of 13C Chemical Shifts
Authors: Tabeta Ryoko , Saitô Hazime 
Published: July 2006

Abstract
We recorded high-resolution solid-state 13C NMR spectra of ethylene oxide oligomers, cryptands, and crown ethers complexed with metal ions, determined by cross polarization-magic angle spinning (CP-MAS) NMR method. It is found that peak-intensities of these complexes are significantly enhanced by the presence of metal ions which act toward conformational fixation of flexible ligand molecules. The 13C chemical shifts of ethylene oxide oligomers complexed with HgCl2 or CdCl2 as open-chain analogues of crown ethers were successfully related with a pair of torsion angles of nearby single bonds. 13C Chemical shifts of cyclic ionophores were displaced (up to 6 ppm) together with conformational changes of ligand molecules. In addition, the 13C chemical shifts of the carbons neighbored with nitrogen atoms of cryptands [2.2.2] and [2.2.1] were well related with a pair of torsion angles of neaby bonds. Further, we found that several kinds of metal complexes with cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 gave rise to substantially different spectral profiles, resulting in the occurrence of significant conformational changes of these ligand molecules as a result of complex formation.