bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Electronic Structures of Cu(II) Complexes as Determined by Means of the Configurational Interaction Method
Authors: Kobinata Shunsuke 
Published: July 2006

Abstract
The electronic structures of Cu(II) complexes with D4h effective molecular symmetry have been investigated by means of the configurational interaction method. The locally-excited configurations of the central metal ion and the charge-transfer configurations corresponding to an electron transfer from the ligand system to the central metal ion have been taken into account. A correspondence with the crystal-field treatment has been obtained using the partitioning technique of solving the secular equation. The energies of the charge-transfer configurations, the resonance integrals, and the electrostatic contribution, Dsion, were determined so as to fit the observed d-d spectra.
Acid Dissociation Constants of Some Histidine-containing Peptides and Formation Constants of Their Metal Complexes
Authors: Yokoyama Akira , Aiba Hiroji , Tanaka Hisashi 
Published: July 2006

Abstract
Glycyl-l-histidine, l-histidylglycine, glycylglycyl-l-histidine, glycyl-l-histidylglycine, and l-histidylglycylglycine were synthesized by the carbobenzoxy azide procedure. The acid dissociation constants of these peptides and their related compounds were determined from the potentiometric titration curves of 0.01 M solutions at 21°C. The dissociation of one ionization group is greatly influenced by the charge on the other groups. The formation constants of metal complexes of l-histidylglycine, l-histidylglycylglycine, and l-3-benzylhistidine were calculated by the least-squares method from the titration curves of the solution containing the ligand (0.01 M) and metal in the molar ratio 2: 1, assuming the formation of 1: 1 and 2: 1 normal complexes (ML+ and ML2), and the results were compared with those of l-histidine-metal complexes. For any metal ion, the order of formation constants was found to be histidine≈3-benzylhistidine&gt;histidylglycine&gt;histidylglycylglycine, in agreement with that of the basicity of amino and imidazole groups. In these metal complexes, metal ion is considered to bind through amino, imidazole, and carboxyl or carbonyl groups of histidine residue.
The Reaction of α-Ethoxybenzyl t-Butyl Peroxide with Grignard Reagents
Authors: Okubo Masao , Sait\={o} Hiroshi , Tomiyoshi Toshiaki 
Published: July 2006

Abstract
Effect of the ethoxyl group of the peroxide in the title was examined. Reactivities of some peroxides having oxygen- and nitrogen-atom adjacent to O-O linkage against magnesium compounds and alkali iodide were compared, and effect of the coordination of heteroatoms to the cationic species was discussed.
Vibrational Spectra and Normal Coordinate Analysis of Bis(methylthio)mercury
Authors: Iwasaki Noriko , Tomooka Jo , Toyoda Koichi 
Published: July 2006

Abstract
The IR and Raman spectra of bis(methylthio)mercury and methyl(methylthio)mercury were studied. Fundamental vibrations were assigned as follows: frequencies 698, 330, 530 and 174 cm−1 to C–S stretching, S–Hg stretching, C–Hg stretching and C–S–Hg bending vibrations, respectively. The fundamental vibrations were confirmed by normal coordinate analysis. The force constants of S–C and S–Hg stretching vibrations were estimated to be 2.16 and 1.5 md/Å, respectively.
A Study of Quenching of Triplets by Ferrocene
Authors: Kikuchi Masae , Kikuchi Koichi , Kokubun Hiroshi 
Published: July 2006

Abstract
Rate constants for quenching of several triplets by ferrocene have been determined in ethanol. Most triplets have been found to be deactivated by ferrocene, yielding no observable transient absorption. The rate constant increases with increasing triplet energy in the range 8000–17000 cm−1. The quenching mechanism has been discussed, the lowest triplet level of ferrocene being estimated to be 15000±1000 cm−1.
Copper(II) Complexes of l-Histidylglycine and l-Histidylglycylglycine in Aqueous Solution
Authors: Aiba Hiroji , Yokoyama Akira , Tanaka Hisashi 
Published: July 2006

Abstract
Equilibrium constants were determined in the complex formations of l-histidylgylcine (HG) and l-histidylglycylglycine (HGG) with copper(II) ion in aqueous solution by potentiometric titration, and the structures of the complexes were discussed based on the observations in the titration and infrared and electronic absorption spectra. In the acid region, a cationic chelate, in which copper(II) binds to nitrogen atoms of amino and imidazole groups, is formed. In the neutral region, deprotonation of the peptide amide group occurs to form a dimer, in which four coordination positions of copper(II) are occupied by nitrogen atoms of deprotonated amide and amino groups and an oxygen atom of carboxyl or carbonyl group in one molecule and a nitrogen atom of imidazole group of another molecule. In HGG–Cu(II) system, the dimer is decomposed in the alkaline region with further deprotonation of the second peptide amide group to form an anionic chelate as in the case of the glycylglycylglycine–Cu(II) complex.
ESR Study on Transient Radicals in Plastic Crystals under
Authors: Shiraishi Hirotsugu , Kadoi Hajime , Hasegawa Kenichi , Tabata Yoneho , Oshima Keichi 
Published: July 2006

Abstract
An apparatus was constructed for ESR measurements during electron irradiation, and the behavior of transient radicals in the plastic crystals of cyclohexane (CyH) and 2,2,3,3-tetramethylbutane (TMB) was investigated. It was found from the experiment that cyclohexyl radical produced by irradiation of CyH decays with a rate constant of 2×10−8 exp (−7.9 kcal/RT) cm3/s. The rate constant is in good agreement with the results reported by Buben et al. On the other hand, radicals formed in irradiated TMB were assigned to be
(Remark: Graphics omitted.)
from the present results. It was shown from the results that the assignment made by Marx et al. before should be corrected to some extent. In the plastic crystals of CyH and TMB, it was suggested that the decay reactions of the observed radicals are controlled by the diffusional migration of the radicals. The analysis of radiolytic products of TMB was also made, and the results were compared with the results of ESR observation.
A Solubility Study of Coacervates of Magnesium, Calcium and Aluminum Highpolyphosphates in Acid Solutions
Authors: Kanazawa Takafumi , Umegaki Takao , Kitajima Y\={o}z\={o} , Ogawa Takeshi 
Published: July 2006

Abstract
Dissolution of the highpolyphosphate coacervates of magnesium, calcium and aluminum was studied in order to understand the conformational feature of polyphosphate chains in the coacervates. Electrical conductivity and viscosity of the coacervate solutions were measured. Paper chromatographic technique was employed for the analysis of the solutions. It was concluded that the polyphosphates dissolve into acid solvents without cleavage of phosphate chains, the degree in the extension of the chains being considerably small. Dissolution processes of the three coacervates were compared. Optimum conditions on the syntheses of the threadforming coacervates are given.
Copper(II) Complexes of Glycyl-l-histidine, Glycyl-l-histidylglycine, and Glycylglycyl-l-histidine in Aqueous Solution
Authors: Aiba Hiroji , Yokoyama Akira , Tanaka Hisashi 
Published: July 2006

Abstract
The complex formation of glycyl-l-histidine, glycyl-l-histidylglycine, and glycylglycyl-l-histidine with copper (II) ion in aqueous solutions containing equimolar amounts of copper(II) and the respective ligand was investigated by potentiometric and visible spectrophotometric methods. The presence of the following copper (II) complex species was assumed: CuLH2+, CuX, and CunYnn− for glycyl-l-histidine-copper(II) and glycyl-l-histidylglycine–copper(II) systems, and CuLH2+, CuY−, and CuZ2− for glycylglycyl-l-histidine-copper(II) system, where LH is the neutral species of the ligand and LH=XH2=YH3=ZH4. The formation and ionization constants were obtained graphically, and the distribution of copper(II) among the complex species was calculated for each system. The results indicate that copper(II) ions are bound to the imidazole and carboxyl (or carbonyl) groups in CuLH2+ and to the amino, imidazole, and deprotonated amide groups in CuX, CuY−, and CuZ2−. The spectral blue shift accompanying a deprotonation in the region from a=4 to 5 in the glycyl-l-histidine and glycyl-l-histidylglycine copper(II) systems indicates the formation of a polymer complex CunYnn− in which the imidazole ring acts as a bridge to connect copper atoms, where a represents moles of KOH added per completely protonated ligand.
Total Syntheses of Holomycin, Thiolutin, and Aureothricin
Authors: Hagio Katsuaki , Yoneda Naoto 
Published: July 2006

Abstract
The reactions of 4-benzylthio-5-benzylthiomethyl-3-hydroxy-2-oxo-2,5-dihydrofuran with ammonia and primary amines gave 3-amino-4-benzylthio-5-benzylthiomethyl-3-pyrrolin-2-one derivatives. 3-Acylamino-4-benzylthio-5-benzylthiomethylene-3-pyrrolin-2-one derivatives, including the intermediate of the synthesis of holomycin by Büchi, were prepared by the treatment of the 3-acylaminolactams derived from the 3-aminolactams with chloranil or DDQ. Thiolutin and aureothricin were also synthesized from 3-acetamido- and 3-propionamido-4-benzylthio-5-benzylthiomethylene-1-methyl-3-pyrrolin-2-one respectively.
A New Lanthanoid Double Trifluoride Compound (Er0.3Nd0.7)F3
Authors: Okamura Kiyohito , Yajima Seishi 
Published: July 2006

Abstract
A new compound, (Er0.3Nd0.7)F3, in the ErF3–NdF3 system was prepared by the solid state reaction of NdF3(hexagonal LaF3-type) and ErF3 (orthorhombic YF3-type). It was found to be of an isostructure with ErF3 of the space group Pnma. Structural data are compared with those of ErF3.
Reaction Paths in the Photochemical Isomerization between cis-Butadiene and Cyclobutene
Authors: Kikuchi Osamu 
Published: July 2006

Abstract
During the disrotatory process of the photoinduced cycloaddition of cis-butadiene, two lower symmetric states play an important role and the ground state of cyclobutene is formed directly through a radiationless transition between these two states.
On the Behavior of O2− and O− Radicals over V2O5–SiO2 Catalyst
Authors: Yoshida Satohiro , Matsuzaki Tokuo , Kashiwazaki Tomonori , Mori Kozo , Tarama Kimio 
Published: July 2006

Abstract
The behavior of oxygen, O2− and O− radicals adsorbed on the partially reduced V2O5–SiO2 catalysts has been investigated. Oxygen is adsorbed mainly in a molecular state at room temperature, the sum of amounts of paramagnetic adsorbed species O2− and O− being less than 10% of total amount of adsorbed oxygen. High degree of reduction, high content of V2O5 and low pressure of oxygen at adsorption equilibrium are favorable for the formation of O− radical. It was confirmed by the quantitative analysis of reaction products and the adsorbed species that O2−, not O−, is the active species in the oxidation of propylene at room temperature. A mechanism involving an intermediate of an epoxide structure was proposed.
Extrinsic Photoconductivity of N-Ethylcarbazole Single Crystals
Authors: Kato Keishi , Yokoyama Masaaki , Mikawa Hiroshi 
Published: July 2006

Abstract
An extrinsic photocurrent was observed in pure N-ethylcarbazole single crystal, contrary to the current view that it does not exist in N-isopropylcarbazole. It was reduced to a great extent in anthracene-containing crystal due to the decrease in carrier quantum yield caused by the energy transfer from N-ethylcarbazole (host) to anthracene (guest) molecules.
The Kinetics and Mechanism of Hydrogen Adsorption and Hydrogen–Deuterium Equilibration on the Copper Surface
Authors: Kiyomiya Makoto , Momma Naohiro , Yasumori Iwao 
Published: July 2006

Abstract
The mechanism of H2–D2 equilibration reaction over the copper surface was studied in the 40–90 °C range of temperature and in the pressure range of 4–45 Torr. From the studies of the hydrogen adsorption and the reaction between gaseous deuterium and preadsorbed hydrogen, the reaction was confirmed to proceed via combination between hydrogen and deuterium atoms on the surface. The rate constants for the adsorption and the desorption were optimized by a computer simulation of the reaction-time course and were found to be in satisfactory agreement with the observed results. A marked isotope effect was found in these rates; its influence on the partial pressure dependence of the reaction was discussed.
The Crystal and Molecular Structure of β-Lactose
Authors: Hirotsu Ken , Shimada Akira 
Published: July 2006

Abstract
The crystal structure of β-lactose (C12H22O11) was solved by direct phasing methods with integrated photographic intensity data. The structure was refined by the anisotropic least-squares method to give a final R value of 0.068 for the observed reflections. The space group is P21 with Z=2 and with unit cell dimensions of a=10.839 (6), b=13.349 (6), c=4.954 (5) Å, and β=91.31 (9)°. All the hydrogen atoms were located on different syntheses. The crystals are nearly isostructural with those of β-cellobiose except for the axial O(4) atom. The exocyclic C(5)–C(6) and C(5′)–C(6′) bonds are significantly shorter than the other C–C bonds. The lengths of the two ring C–O bonds are unequal in the galactose unit and equal in the glucose unit. The C(1)–O(1) and C(1′)–O(1′) bond lengths are shorter by 0.015 Å and 0.030 Å than the mean exocyclic C–O length of 1.417 Å. The structure contains an intramolecular hydrogen bond and exhibits an asymmetrical twist about the bridge bond. All the oxygen atoms, except the bridge oxygen atom, are involved in the hydrogen-bonding network, which comprises two terminating chains.
Vibrational Energy Transfer of Some X2CO-type Molecules on Collision with Argon
Authors: Yonezawa Yoshiro , Fueno Takayuki 
Published: July 2006

Abstract
Vibrational excitation of X2CO-type polyatomic molecules (X=F, Cl, Br, and H) on collision with an argon atom at temperatures 1000–3000 K was treated by the SSH-Tanczos method with a more tractable formula of average vibrational factor. Bending modes are more easily excited than bond-stretching modes in carbonyl halides. Excitation of the carbonyl stretching mode, the most difficult to occur in T–V process, becomes realizable when coupled with other modes to satisfy the near-resonance conditions.
Asymmetric Synthesis in the Oxymercuration Reaction Using Optically Active Mercuric Salts
Authors: Sugita Toshio , Yamasaki Yasuo , Itoh Osamu , Ichikawa Katsuhiko 
Published: July 2006

Abstract
The oxymercuration-demercuration of styrene with optically active mercuric tartrate, 2-phenylpropionate, mandelate, camphorate, menthoxyacetate, and monomethyl tartrate resulted in a partial asymmetric synthesis of 1-phenylethanol. When mercuric tartrate was used, exceptionally high optical yields (25–32%) were observed. The mechanisms for the asymmetric synthesis are discussed.
Crystal and Molecular Structure of ω-Amino Acids, ω-Amino-Sulfonic Acids and Their Derivatives. VII. The Crystal and Molecular Structure of Dl-Carnitine Hydrochloride
Authors: Tomita Ken-ichi , Urabe Keiko , Kim Yang Bae , Fujiwara Takaji 
Published: July 2006

Abstract
The crystal structure of Dl-carnitine hydrochloride, C7H15NO3·HCl, was determined by the heavy atom method using X-ray diffraction data on a Weissenberg photograph, and refined by the least-squares method to an R-factor of 0.13 for 1969 independent reflections. The crystals are monoclinic space group P21⁄c, Z=4, with a=6.77(1), b=11.41(2), c=15.10(3) Å and β=120.1(1)°. By protonation at carboxyl oxygen atom, carnitine molecule has the cationic form, N+(CH3)3CH2CH(OH)CH2COOH, with trans-zigzag skeletal configuration as similar as γ-amino-β-hydroxybutyric acid. The Cl− ion mediates between adjacent carnitine cations by two O–H···Cl− hydrogen bonds to form infinite chain elongated along the c-axis. The correlation between molecular structure and biological activity was also discussed.
Codimerization of Butadiene and Ethylene Catalyzed by σ-Arylnickel(II) Compound in the Presence of Boron Trifluoride Etherate
Authors: Kawata Noboru , Maruya Ken-ichi , Mizoroki Tsutomu , Ozaki Atsumu 
Published: July 2006

Abstract
The codimerization of butadiene with ethylene was studied with use of the catalyst system consisting of bis(triphenylphosphine)σ-arylnickel(II) halide and boron trifluoride etherate in methylene dichloride. The codimerization took place readily at 15 °C under 20 kg/cm2 to give trans- and cis-1,4-hexadiene and 3-methyl-1,4-pentadiene. A catalytic amount of water significantly enhanced the catalytic activity. The reaction path to form the codimers is discussed in terms of the variation in product distribution with time and the reaction kinetics.
A Polarographic Study of the Rates of the Dissociation Reactions of Aminopolycarboxylato–zinc(II), –lead(II), and –cadmium(II) Complexes
Authors: Kodama Mutsuo , Namekawa Kyoko , Horiuchi Takashi 
Published: July 2006

Abstract
The rates and the mechanisms of the dissociation reactions of aminopolycarboxylato zinc(II), lead(II), and cadmium(II) complexes were studied by analyzing their kinetic waves by conventional DC polarography. The dissociations of the zinc(II)–HIDA and–NTA complexes and the cadmium(II)– and lead(II)–HIDA complexes in an acetate buffer solution, and those of protonated lead(II)–EDTA and –EDTA–OH complexes were found to proceed through the following direct dissociation mechanisms:
i) HIDA and NTA systems
2&MX_2^2-2m\ightleftharpoonsMX^2-m+X^m-& &in a rapid equil.
&MX^2-m\ightleftharpoonsM^2++X^m-& &r.d.s.
\intertextii) EDTA and EDTA-OH systems
&MHY^3-n\ightleftharpoonsM^2++HY^1-n& &r.d.s.
On the other hand, the dissociation of the zinc(II)-EDTA-OH and its protonated DTPA complexes gave this rate law: -d[MHiY2+i−m]/dt (i=0 or 1)=kdH·[H+]·[MHiY2+i−m]. From a comparison of the observed rate constants, the zinc(II)–HIDA and –NTA, lead(II)- and cadmium(II)–HIDA and protonated lead(II)–EDTA and –EDTA–OH complexes are concluded to dissociate through a simple glycinate reaction intermediate, and the zinc(II)–EDTA–OH and its protonated DTPA complexes, through a glycinate reaction intermediate which includes polyfurcated hydrogen bonds.
Crystal Structure of Chloro-1-(2-thiazolylazo)-2-naphtholatopalladium(II) Dioxane Solvate
Authors: Kurahashi Masayasu 
Published: July 2006

Abstract
The crystals of chloro-1-(2-thiazolylazo)-2-naphtholatopalladium(II) dioxane solvate, [PdCl(TAN)]·C4H8O2, are orthorhombic and of space group Pbcm, with unit cell dimensions: a=8.44(2), b=30.97(4) and c=6.82(2) Å and Z=4. The structure was determined by the heavy-atom method and refined by the least-squares procedure to give an R value of 0.097 for 1392 observed reflections. The crystallographic mirror plane normal to the c-axis coincides with the molecular plane of [PdCl(TAN)]. The 1-(2-thiazolylazo)-2-naphtholato group, i.e., TAN, is a terdentate ligand; the phenolic oxygen atom, azo nitrogen atom and thiazole nitrogen atom are coordinated to the palladium atom to form two five-membered chelate rinsgs. The fourth coordination position is occupied by a chlorine atom.
Formation and Collapse of Mixed Monolayers of Trilaurin with Cholesterol and with Tristearin
Authors: Nakagaki Masayuki , Funasaki Noriaki 
Published: July 2006

Abstract
The surface pressure-area curves of mixed monolayers and the equilibrium spreading pressure of solid mixtures were measured at 25 °C for cholesterol and trilaurin as well as tristearin and trilaurin. The phase diagrams of these mixtures were obtained by the measurement of the melting point. From two curves, one representing the relation between the collapse pressure (if the mixed monolayer was not overcompressed) and the composition of mixed monolayer, and the other representing the relation between the equilibrium spreading pressure and the composition of solid mixture, it was shown that the compositions of the mixed monolayer and the solid mixture coexisting in equilibrium were obtained. It was found that when the mixed monolayer of cholesterol and trilaurin was compressed, pure trilaurin began to collapse and deposit, and that the mixed monolayer of tristearin and trilaurin was apt to be overcompressed. It was concluded on the basis of phase rule and thermodynamics for plane interfaces that the equilibrium spreading pressure is constant regardless of the composition of solid mixture if the solid mixture consists of two phases of mixed crystals, and that cholesterol and trilaurin form a regular solution in mixed monolayer.
Effects of the Wavelength and the Matrix on the Photopolymerization of 2,5-Distyrylpyrazine and Its Related Compounds and on Their Photodepolymerization
Authors: Suzuki Yasuzo , Tamaki Takashi , Hasegawa Masaki 
Published: July 2006

Abstract
The solution photopolymerization of 2,5-distyrylpyrazine (DSP) and its related compounds with the general formula of Ar–CH=CH–Ar′–CH=CH–Ar, where Ar and Ar′ represent aryl and arylene groups respectively, have been investigated. All diolefines were converted in good yields into amorphous oligomers with cyclobutane in the main chain on the exclusive excitation of the monomer molecules, while, in the crystalline state, only DSP and 1,4-bis[β-pyridyl-(2)-vinyl] benzene are known to yield highly crystalline oligomers under the same light. All the oligomers were found to be photodepolymerized to the original monomers in the solution on the excitation of the terminal groups of these oligomers. In consequence, a photoreverse scheme has been demonstrated between the diolefinic monomer and the oligomer, depending on the excitation wavelength. Poly-DSP was photodepolymerized into the monomer in tifluoroacetic acid solution, while amorphous poly-DSP in film was readily photooxidized in the air under sunlight. From the photochemical behavior of DSP, oligo-DSP, and poly-DSP, it was found that chemically the same substance, oligo-DSP, behaved in three ways, photopolymerization, photodepolymerization and no photoreaction, according to the physical state. Such a matrix effect is discussed from the point of view of topochemical reaction.
The Temperature Dependence of the G-Values of Nitrogen from the Gas-phase γ-Radiolysis of C3-Hydrocarbons in the Presence of Nitrous Oxide
Authors: Okazaki Kiyoshi , Yugeta Rei , Kowari Ken-ichi , Sato Shin 
Published: July 2006

Abstract
The G-values of nitrogen from the gas-phase γ-radiolysis of the C3-hydrocarbons (propane, propylene, and cyclopropane) in the presence of nitrons oxide have been measured at the temperatures from −35 to 150 °C. The G-values increased with an increase in the pressure of N2O and were saturated at about 4 mol% of N2O. The saturated values, G(N2)max’s showed characteristic temperature dependences. In propane, they scarcely changed with the temperature and stayed at around 2 Ge. Here Ge is the G-value of electrons estimated from the W-value of the hydrocarbon. In propylene, the G(N2)max changed from Ge at −35 °C to about 2 Ge at 150 °C, while in cyclopropane it changed from Ge at −35 °C to 4.5 Ge at 100 °C. Possible reaction mechanisms to explain these results have been discussed.
ESR Studies of the Triplet State Dimers of the Salicylaldehyde Schiff Base Complexes of Copper(II) in Toluene and in Chloroform
Authors: Chikira Makoto , Yokoi Hiroshi , Isobe Taro 
Published: July 2006

Abstract
The ESR spectra of triplet-state dimers have been obtained for various bidentate and quadridentate salicylaldehyde Schiff base complexes of copper(II) in frozen solutions. The spectra have been analysed on the basis of the previously-obtained results concerning the non-coaxial g and fine-structure tensors. The results indicate that the angles between the g|| axis and the copper-copper axis of the dimers for the quadridentate Schiff base complexes are considerably smaller than those for the bidentate ones. Each of the actually-measured ESR spectra, however, consisted of two mutually-overlapping spectra; one is due to dimers (M2), and the other, to monomers (M). The equilibrium constant for 2M\ightleftharpoonsM2 has been estimated by comparing the ESR spectral intensities of the two species. The factors which govern the dimer formations have been discussed in some detail.