bluuebunny/crossref_metadata_2025_split huggingface dataset:
Polarographic Study of Monosaccharides in Unbuffered Solution and Its Application to the Determination of the Mutarotation Rate Constants
Authors: Ikeda Tokuji , Senda Mitsugi 
Published: July 2006

Abstract
The polarographic behavior of monosaccharides in unbuffered neutral solution was investigated. The limiting current was ascertained to be an autocatalytic current which could be caused by the production of hydroxyl ion at the electrode surface. Equations for the characteristic limiting current and for the shape of current-potential curve were derived by use of the reaction layer concept. Experimental results for d-glucose, d-galactose, and d-xylose were fairly well expressed by these equations. The wave can also be applied to the determination of the mutarotation rate constants of monosaccharides, the values obtained (d-glucose: 0.53×10−3 s−1, d-galactose: 0.54×10−3 s−1, and d-xylose: 1.31×10−3 s-−1) being in fairly good agreement with those obtained by the polarimetric method (d-glucose: 0.4×10−3 s−1, d-galactose: 0.5×10−3 s−1, and d-xylose: 1.3×103 s−1).
The Metal Ammine Cyanide Aromatics Clathrates. XVI. Wide-Line NMR Studies of the Three-Spin Systems of Ligand Ammonia in Paramagnetic Hofmann-type Clathrates
Authors: Nakano Taku 
Published: July 2006

Abstract
Wide-line NMR studies of ammonia molecules in Hofmann-type clathrates with the general formula of M(NH3)2M′(CN)4·2C6D6 are reported. In the Hofmann-type clathrates, two ammonia molecules coordinate to the paramagnetic metal ions in trans positions and have only a slight interaction with each other. In powder samples, the proton NMR spectra of ammonia give fine structures with three components, which are caused by dipolar interaction between protons of the rotating triangular three-spin system. The signals shift to the higher-field side under the influence of the paramagnetic moments of the metal ions. The temperature dependence of the shifts and line shapes, where M is iron(II), cobalt(II), nickel(II), and copper(II), will be reported on. No rigid ammonia was found, even at the temperature of liquid nitrogen.
Polarographic Reductions of Some Alkali and Alkaline Earth Metal Ions in Dimethylacetamide. Effect of Cation of the Supporting Electrolyte
Authors: Izutsu Kosuke , Sakura Sachiko , Fujinaga Taitiro 
Published: July 2006

Abstract
Polarographic reductions of lithium, barium, strontium, and calcium ions in dimethylacetamide (DMA) have been examined in the supporting electrolytes of various kinds of tetraalkylammonium perchlorates. As having been observed in hexamethylphosphoramide, the reductions of these metal ions in DMA are influenced significantly by the cation of the supporting electrolyte. When the cation of the supporting electrolyte is small in size and easily adsorbed onto the negatively charged electrode surface, as in the case in Et4NClO4, the reductions of these metal ions are difficult and they either do not occur at all until the reduction of the supporting electrolyte itself or, if they occur, the limiting currents are small and controlled by some preceding processes. With the increase of the cationic size of the supporting electrolyte, the reductions become much easier. Thus, in Bu4NClO4 and in Hex4NClO4, these metal ions are reduced almost reversibly. The effect of cation of the supporting electrolyte on the reduction of lithium ion has also been examined briefly in dimethylsulfoxide, dimethylformamide and propylenecarbonate.
Autoxidation of Trimethyl Phosphite Initiated by One-Electron Transfer from Phosphite to Quinones
Authors: Ogata Yoshiro , Yamashita Mitsuji 
Published: July 2006

Abstract
The reaction of trimethyl phosphite (I) with acenaphthenequinone (II) under air affords quantitatively trimethyl phosphate (III) and 1:2 adduct (IV), which was converted into δ-lactone (V) and III by addition of water, while only IV was obtained quantitatively under N2 atmosphere. ESR and UV spectra, decolorization of 1,1-diphenyl-2-picrylhydrazyl (DPPH), and initiation of styrene polymerization suggest the transient formation of radical ions VI and VII. The rate law for the autoxidation of I is expressed as: v=k[I][II]0.7−1.0. The reaction in chloroform proceeds faster than that in dioxane. The reaction of I with chloranil is much slower, and no reaction occurs with phenanthrenequinone and anthraquinone which have low reduction potentials. A mechanism which involves one-electron transfer from phosphite to acenaphthenequinone followed by autoxidation was proposed for the reaction under air.
Measurement of Negative Ions Formed by Electron Impact. IX. Negative Ion Mass Spectra and Ionization Efficiency Curves of Negative Ions of m⁄e 25, 26, 27, 38, 39, 40 and 50 from Acrylonitrile
Authors: Tsuda Satoru , Yokohata Akira , Umaba Toshikatsu 
Published: July 2006

Abstract
Negative ion mass spectra of acrylonitrile were measured for the electron energies of 80, 40 and 9.5 eV. Emphasis was laid on the abundance of the negative ions relative to the positive ions measured for the energies of 80, 40 and 15 eV, respectively. The ionization efficiency (IE) curves were also determined up to 25 eV for the ions of m⁄e 25(C2H−), 26(CN−), 27(HCN−), 38(C2N−), 39(CHCN−), 40(CH2CN−) and 50(C3N−). The electron impact of 80 eV and 40 eV gave almost the same distribution of m⁄e for negative ion mass spectra. Besides the most intense peak of CN− ions, relatively strong peaks of C3N−, C2H−, C2− and C2N− ions were observed. In 9.5 eV, CN− ions predominated over other ions. Yields of the ions showed a good linearity against the pressure in the range used for usual chemical analysis, irrespective of electron energy. Comparison of the yield of CN− ions with that of C2H3CN+ gave the values 1.2×104 and 1.9×104 for C2H3CN+/CN− at 80 eV and 40 eV, respectively, and 47.6 at 9.5 eV (15 eV for the positive ions). The plausible reaction schemes expected to occur at each onset observed in the IE curves were also sought thermochemically by using ΔHf values of the reactant and products. A value \gtrsim2 eV was obtained for the electron affinity of C2H.
Time-Resolved Fluorescence Studies on the Dual Fluorescence Process of p-(Dimethylamino)benzonitrile
Authors: Nakashima Nobuaki , Inoue Hidetoshi , Mataga Noboru , Yamanaka Chiyoe 
Published: July 2006

Abstract
Time-resolved fluorescence spectra and the fluorescence rise and decay curves have been measured for p-(N,N-dimethylamino)-benzonitrile. The results demonstrate the relaxation process to be due to the interaction between the solvent and the 1La state of the solute, leading to dual fluorescence.
Mass Spectrometric Study of the Primary Processes in Photochemical Reactions I. Photodecomposition of 1,1′-Azopropane
Authors: Yamashita Shigeru , Hayakawa Teruo 
Published: July 2006

Abstract
Primary processes of the photolysis of 1,1′-azopropane were studied using a high intensity light beam and a collision-free photochemical reactor incorporated in the ion-source of a mass spectrometer. The photofragments produced by the following three one-bond fission primary processes were found.
& CH_3CH_2CH_2N_2CH_2CH_2CH_3+hν→CH_3CH_2CH_2N_2CH_2+CH_2CH_3\labeleq1
& CH_3CH_2CH_2N_2CH_2CH_2CH_3+hν→CH_3CH_2CH_2N_2+CH_2CH_2CH_3\labeleq2
& CH_3CH_2CH_2N_2CH_2CH_2CH_3+hν→2CH_3CH_2CH_2N\labeleq3
The lifetime of these photofragments seems to be longer than 50 μs considering the experimental conditions.
Studies on Intermolecular Complex Formation. IV. Crystal Structure of Cytosine-Resorcylic acid 2:1 Complex monohydrate
Authors: Tamura Chihiro , Sato Sadao , Hata Tadashi 
Published: July 2006

Abstract
The crystal and molecular structure of a cytosine and resorcylic acid complex monohydrate has been solved by the direct method. The molecular complex is formed by two moles of cytosine and one mole of resorcylic acid. The crystals are monoclinic, with a space group of P21/n, and with a=8.335, b=20.605, c=10.159 Å, and β=95.5°. The final R-factor for 1820 reflections is 0.100. Resorcylic acid is hydrogen-bonded to one of the cytosine molecules with one hydrogen bond, and the two cytosine molecules with one hydrogen bond, and the two cytosine molecules are associated with three hydrogen bonds in a system similar to that of the guanine-cytosine hydrogen bond in the Watson-Crick model.
Investigation on Low-spin Cobalt(II) Complexes. III. Structural, Optical and Magnetic Properties of Five-coordinate Complexes
Authors: Nishida Yuzo , Shimohori Hideharu 
Published: July 2006

Abstract
ESR and reflectance spectra of low-spin five-coordinate cobalt(II) complexes [CoXdpe2]Y, where dpe represents 1,2-bis(diphenylphosphino)ethane and X,Y are Cl−, Br−, NCS−, NO3− and ClO4− anions, were measured. From the results it was inferred that the structures of [CoCldpe2]ClO4 and [CoBrdpe2]ClO4 are distorted trigonal bipyramids whereas those [CoNCSdpe2]ClO4 and [CoNO3dpe2]NO3 are square pyramids.
The Crystal Structure of (−)589-Acetylacetonatobis(trimethylenediamine)cobalt(III) Arsenic(V) (+)-Tartrate Monohydrate
Authors: Matsumoto Keiji , Kawaguchi Hiroshi , Kuroya Hisao , Kawaguchi Shinichi 
Published: July 2006

Abstract
The crystal structure of (−)589-[Co acac tn2][As-(+)-tart]2·H2O has been determined by the X-ray diffraction method. The crystals are monoclinic, with lattice constants of a=12.02(1) Å, b=13.73(2) Å, c=9.02(1) Å, and β=107.4(3)°, and with the space group of P21, containing two formula units in a cell. The structure was determined by the application of Patterson and Fourier techniques and was refined by the least-squares method to an R factor of 10.4%. The absolute configuration of (−)589-[Co acac tn2]2+ can be denoted as Δ. The two Co-tn chelate rings assume the chair form, and the Co-acac chelate ring is almost planar. The geometry of [As-(+)-tart]22− is identical with that of [Sb-(+)-tart]22−.
A Kinetic Study of the Ligand Substitution Reaction of Tetramethylenediaminetetraacetatocobaltate(II) with Trimethylenediaminetetraacetate
Authors: Ogino Hiroshi , Watanabe Toshiyuki , Chung Jong-Jae , Tanaka Nobuyuki 
Published: July 2006

Abstract
The kinetics of the ligand substitution reaction of tetramethylenediaminetetraacetatocobaltate(II)(cobalt(II)–TDTA) with trimethylenediaminetetraacetate (TRDTA) was investigated by two different polarographic methods. The kinetic data at pH 4.9 to 5.6 were obtained by means of a conventional method in which the reaction was initiated by the mixing of two reactant solutions and was followed polarographically. However, this method could not be applied to solutions with pH values lower than 4.9, for the rate of the reaction is immeasurably fast in such a low pH region. The kinetic data at pH values down to 3.7 were obtained by analyses of the polarographic current which was observed in solutions containing TRDTA and the substitution-inert cobalt(III)–TDTA complex. From these data, it was found that the reaction proceeds through four simultaneous reaction paths, two paths of which are the nucleophilic substitution reactions, while the others are the dissociation reactions of cobalt(II)–TDTA complex ions.
Structural Studies of Tryptophan Metabolites by X-ray Diffraction Method. II. The Crystal and Molecular Structure of Tryptamine Hydrochloride
Authors: Wakahara Akio , Fujiwara Takaji , Tomita Ken-ichi 
Published: July 2006

Abstract
The crystal structure of tryptamine hydrochloride has been solved by the application of the symbolic addition method, and refined by successive Fourier syntheses and least-squares procedures. The crystals are orthorhombic, space group Pbca, with lattice parameters a=8.545, b=10.025 and c=24.252 Å. All the positions of hydrogen atoms were found in the difference Fourier map and included in the refinement. The ethylamine side chain bound to the indole ring is in a folded configuration as found in the crystal structure of serotonin picrate monohydrate. A weakly basic nitrogen atom of the indole ring takes part in the hydrogen bonding with the adjacent ion. Every chloride ion behaves as an acceptor for four hydrogen bonds. This is in line with the absence of any marked cleavage where indole rings are packed together to form a pleated sheet and a three-dimensional network structure is essentially stabilized by the hydrogen bond formation.
Photochemical Reaction of Diaryl Thioketones in Ethereal Solutions. A Stable Transient Free-Radical
Authors: Kito Noboru , Ohno Atsuyoshi 
Published: July 2006

Abstract
Photochemical reactions of thiobenzophenone and its 4,4′-dimethoxy derivative in ethereal solutions such as tetrahydrofuran and diethyl ether have been studied by means of product analyses and ESR spectroscopy. It was found that the reaction involves quite stable transient free-radicals of the type Ar2CSR. The efficiency of free-radical trapping by diaryl thioketones and the reaction mechanism are discussed.
Kinetic Study of Triplet–Triplet Energy Transfer in Fluid Solution by Means of Laser Pulse Photolysis
Authors: Takemura Takeshi , Baba Hiroaki , Fujita Masahisa 
Published: July 2006

Abstract
The kinetics of triplet-triplet (T-T) energy transfer in fluid solution has been studied by means of laser pulse photolysis with acetophenone as the energy donor and naphthalene as the acceptor. Decay curves of phosphorescence of the donor and rise-and-decay curves of sensitized T-T absorption of the acceptor were obtained. These were analyzed to determine the unimolecular and bimolecular rate constants (denoted by k1 and k2 respectively) for the deactivation processes of the triplet state of donor or acceptor and the rate constant (kt) for the T-T energy transfer. In isooctane at room temperature these rate constants were found to be: k1=0.67×106 sec−1 and k2=2.0×1010 M−1 sec−1 for acetophenone, k2′=1.6×1010 M−1 sec−1 for naphthalene, and kt=1.0×1010 M−1 sec−1. The kt value obtained from the donor phosphorescence is in good agreement with that from the acceptor T-T absorption. The experimental results suggest that T-T transfer and T-T annihilation processes are not strictly diffusion-controlled.
Near-infrared Spectroscopic Studies of the States of Water in Lyotropic Liquid Crystals
Authors: Aizawa Masuo , Suzuki Shuichi 
Published: July 2006

Abstract
The states of water in lyotropic liquid crystals of the polyoxyethylene–nonylphenylether and water system were investigated by means of near-infrared spectroscopic measurements. The states of water were classified into nonbonded, singly-hydrogen-bonded, and doubly-hydrogen-bonded states, and their relative concentrations were calculated from the intensities of the combination bands of 2ν1+ν3 and ν1+ν2+ν3 in the temperature range from 25 to 50 °C. An increase in the hydrogen-bonded water species was found for the liquid crystal. Furthermore, the nonbonded and singly-hydrogen-bonded water species decreased, while the doubly-hydrogen-bonded water species increased in the liquid crystal structure, as compared with ordinary water. The structural properties of the liquid crystal are discussed.
Relationship between Self-Diffusion and Interdiffusion in Gaseous Systems
Authors: Hirakawa Hiromasa , Kamei Yoshinobu , Sugisaki Masayasu , Oishi Yasumichi 
Published: July 2006

Abstract
Self-diffusion coefficients of oxygen and interdiffusion coefficients were measured for the O2–He system at 25 °C under 760 Torr. The interdiffusion coefficients obtained were compared with theoretical values calculated by the kinetic theory and by Darken’s phenomenological theory. The phenomenological equation was tested in comparison with the kinetic theory by making use of the results and the data reported by other investigators. A criterion determining the magnitude or error of the phenomenological equation was given.
The Magnetic Properties of Verdazyl Free Radicals. III. The Anomalous Magnetic Behavior of Symmetrical Triphenylverdazyl
Authors: Azuma Nagao , Yamauchi Jun , Mukai Kazuo , Ohya-Nishiguchi Hiroaki , Deguchi Yasuo 
Published: July 2006

Abstract
The static magnetic susceptibility and the ESR spectra from 1.6 to 300 K have been measured on a powder sample of the titled free radical. The broad maximum in the susceptibility which indicates an antiferromagnetic interaction has been observed at 6.9 K. The broadening of the ESR absorption line and the shift of the g-value have been found in the temperature region below Tmax, in which the susceptibility reached its round maximum. There appeared anomalies in the slope of the susceptibility, the linewidth, and the g-value versus temperature curves in the vicinity of 1.7 K. These anomalies may imply a magnetic-phase transition from the short-range ordered state to the long-range ordered state at about 1.7 K. The existence of a ferromagnetic interaction between the magnetic chains in the triphenylverdazyl radical solid is discussed on the basis of the susceptibility, the spin distribution, and the crystal structure. It is understood qualitatively that the radical with a negative spin density has a latent ferromagnetic interaction in or between the magnetic chains, and that the obsrevation of this interaction greatly depends upon the molecular and crystal structure.
Interaction of Bovine Serum Albumin with Detergent Cations
Authors: Kaneshina Shoji , Tanaka Mitsuru , Kondo Tatsuhiko , Mizuno Tomoaki , Aoki Koichiro 
Published: July 2006

Abstract
The binding isotherms of bovine serum albumin (BSA) with cationic detergents, decyltrimethylammonium bromide, dodecyltrimethylammonium bromide, and tetradecyltrimethylammonium bromide have been determined at temperatures 8 and 25 °C for pH 6.8. The isotherms have also been determined at pH 3.0 and 25 °C. The effect of KBr on the binding of dodecyltrimethylammonium bromide to BSA has been examined at 25 °C for pH 6.8. The results obtained are as follows. (a) The average number of detergent cations bound, \barv, increased with the increase in the length of hydrocarbon chain, (b) the standard free energy changes −ΔG°, calculated from the intrinsic association constants K, were comparable with the cohesive energy change when one methylene group is transferred from the aqueous phase to the hydrocarbon environment on micellization, (c) values of \barv at pH 3.0 differ only slightly from those at pH 6.8 in a wider range of detergent concentration, and (d) the presence of the salt shifted the binding isotherms to the lower detergent concentrations. These results are discussed as regards the nature of micellization of detergents.
Kinetic Studies of Photosensitized Oxidation through Semioxidized Eosine in an Aqueous Solution
Authors: Usui Yoshiharu , Enokido Haru 
Published: July 2006

Abstract
The rate constant for an electron transfer reaction between triplet eosine and potassium tris(oxalato)cobaltate(III) was estimated. The experimental results from flash photolysis indicate that a transient semioxidized eosine exists in a free state. When a substrate was added to the deaerated eosine and complex solution at an optimum concentration, the original dye was restored by electron transfer from a substrate to the semioxidized eosine, sensitized oxidation occurring efficiently. Choosing indole and its derivatives as a substrate, we have obtained the elementary rate constants of the eosine recovery process.
Studies of Photochemical Reactions Using Organic Photosensitizers. III. Direct Photolysis and Biacetyl-photosensitized Decomposition of Azopropanes
Authors: Yamashita Shigeru , Okumura Kuniyasu , Hayakawa Teruo 
Published: July 2006

Abstract
The direct photolyses in the two wavelength regions and the biacetyl-photosensitized decomposition have been studied for l,l′-azo-n-propane and 2,2′-azo-isopropane. The value of kd/kc, the ratio of the disproportionation rate to the combination rate of free radicals, has been found to be slighlty dependent on the exciting wavelength as for n-propyl and isopropyl radicals. The higher the exciting energies, the larger the ratio kd/kc. From the quenching study of biacetyl phosphorescence, it was found that the energy of the excited biacetyl molecule was transferred to the azopropane molecule at every collision.
The Electrochemical Behavior of the Low-valent Transition Metal Complexes. II. Iron(0)-2,2′-Bipyridine Complexes
Authors: Misono Akira , Uchida Yasuzo , Hidai Masanobu , Yamagishi Takamichi , Kageyama Hironori 
Published: July 2006

Abstract
The electroreduction reaction of the zero-valent iron-2,2′-bipyridine complexes (Fe(bipy)2 and Fe(bipy)3) was studied in a hexamethylphosphoric triamide solution by polarography and ESR measurements. In the polarography, Fe(bipy)2 was first reduced at a very less negative potential (E1⁄2=−0.76V vs. Hg pool) than the first wave potential of free bipyridine (−2.37 V vs. Hg pool). In the presence of excess bipyridine, Fe(bipy)2was first reduced at −1.10 V vs. Hg pool corresponding to the second reduction step of the solution of Fe(bipy)2. The visible spectra of the solution of Fe(bipy)2 in the presence of excess bipyridine was different from that of the solution of Fe(bipy)2 only. The signal with hyperfine structure attributable to the anion radical of bipyridine was observed by means of ESR analysis of the solution electrolyzed at the potential corresponding to the second reduction step. From these results, it was concluded that [Fe(bipy)(HMPT)m] was reduced at the first step, and [Fe(bipy)2(HMPT)] was reduced at the second.
Isotopic Exchange Kinetics between Dibenzoylmethane-14C and Its Tris-type Complex with Aluminium (III) in Tetrahydrofuran
Authors: Matsuzawa Kazuyo , Saito Kazuo 
Published: July 2006

Abstract
Isotopic exchange kinetics between [Al(dbm)3] and Hdbm–14C (dbm−, anion of dibenzoylmethane in enol form) has been studied in tetrahydrofuran (THF) at 30 to 55°C. During several half lives the McKay plot gives straight lines, the AB spectrum remaining unchanged. The rate is very small in the absence of catalysts, and accelerated by water and trichloroacetic acid, but not by weak acids and pyridine. The rate is expressed by
R = [complex](k_2[H_2O]+k_3’[acid]+k_3[acid][H_2O])
The Arrhenius plots of k2, k3′, and k3 give an equal Δ\eweq value 25.6 kcal/mol. It appears one of the ligands is present as unidentate in the intermediate state, and the break of the remaining bond is the rate-determining step.
Linear Conjugated Systems Bearing Aromatic Terminal Groups. XIV. On the Electronic Spectral Regularity of α,ω-Diarylpolyenes
Authors: Akiyama Shuzo , Takeuchi Yasuhira , Yasuhara Akio , Nakagawa Masazumi , Nishimoto Kichisuke 
Published: July 2006

Abstract
The bathochromic shift of the longest wavelength absorption maxima (λ) of several series of polyenes along with the increase in number of ethylenic double bond (n) can be expressed excellently by the empirical formula λ=Anx+B. The value of x varies from 0.5 to 0.8 [0.5≤x≤0.8] depending on the nature of terminal groups and the position of linking of polyene chain to terminal aryl nucleus, being x=0.5 in the case of parent polyenes (I) and x=0.8 for di(3-phenanthryl)- (VI) and di(2-fluorenyl)polyenes (VII). The linear relationship could be reproduced fairly well by the HMO method using the usual bond-alternation approximation (βc=c=1.1β; βc-c=0.9β; βc=c=β. C=C denotes aromatic double bond). The calculation based on a modified bond-alternation approximation (βc=c=[1+0.5⁄(n+4)]β; βc-c=[1−0.5⁄(n+4)]β; βc=c=β) which is analogous to that successfully applied to diarylpoly-ynes did not reproduce the spectral regularity of diarylpolyenes. This seems to offer further support for the pertinence of assumption of increasing contribution of cumulenic structure in diarylpolyenes along with the increase in n.