bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, Dehydration Studies, and Cation-Exchange Behavior of a New Phase of Niobium(V) Phosphate
Authors: Qureshi Mohsin , Ahmad Anees , Shakeel Naseem Ahmad , Gupta Anek Pal 
Published: July 2006

Abstract
Twenty-three samples of niobium(V) phosphate have been synthesized under different conditions using niobium sulfate and phosphoric acid solutions. The amorphous sample having the ion-exchange capacity of 1.06 mEq g−1 and niobium to phosphorus mole ratio of 0.670 was studied in detail for its cation-exchange behavior. Molar distribution coefficients for 25 cations have been studied on this gel at pH 1,2,3, and 5.5. Four quantitative separations of Mg2+–Ca2+, Mg2+–Ba2+, Zn2+–Cd2+, and Bi3+–Zn2+ have successfully been achieved on it. The properties of this sample have been compared with those of niobium arsenate, niobium antimonate, and niobium molybdate. A tentative structural formula is proposed for this sample of niobium phosphate on the basis of chemical composition, cation-exchange capacity, pH-titration, IR spectra, T.G.A., water absorption, and heat treatment data.
Photochemical Cis–Trans Isomerization of 5-Styryl-1,3-dimethyluracil
Authors: Shin Eun Ju , An Beom Shu , Shim Sang Chul 
Published: July 2006

Abstract
The cis–trans photoisomerization of 5-styryl-1,3-dimethyluracil is investigated. The fluorescence and photoisomerization quantum yields in various solvents of different viscosity and polarity, the effect of salt, pH, and heavy atom on the fluorescence and photoisomerization, the triplet sensitization of the photoisomerization, and the azulene quenching of the direct and sensitized isomerization indicate the singlet mechanism for the direct photoisomerization of the compound. The laser flash photolysis at room temperature showed a weak triplet–triplet absorption indicating some intersystem crossing from the excited singlet state to the triplet state.
XPS Study of Silica-Supported Copper Catalyst Derived from Binuclear Copper(II) Acetate Monohydrate or Mononuclear Tetraammine Copper(II) Complex
Authors: Kakuta Noriyoshi , Kazusaka Akio , Miyahara Koshiro 
Published: July 2006

Abstract
The surface copper(II) species on a CuO/SiO2 catalyst derived from binuclear copper(II) acetate monohydrate has been studied using XPS in comparison with that from the mononuclear tetraammine copper(II) complex. From the binding energy of Cu 2p3⁄2 peak and the peak ratio of Cu 2p3⁄2 and Si 2p together with the results by EXAFS, it was deduced that the highly dispersed one or two dimensional copper oxide cluster, which is interacted more weakly with SiO2, is developed on the copper(II) acetate monohydrate derived catalyst.
EXAFS Study on One-Dimensional Halogen-Bridged Mixed-Metal (Pd, Pt)Mixed-Valence Complexes
Authors: Ikemoto Isao , Kikuchi Koichi , Iwai Kumiko , Yamashita Masahiro , Nomura Masaharu , Asakura Kiyotaka , Kosugi Nobuhiro , Yakushi Kyuya , Kuroda Haruo 
Published: July 2006

Abstract
The EXAFS spectra of [Pd(en)2X2Pt(en)2](ClO4)4 (en=ethylenediamine, X=Cl, Br, and I) were measured for Pd K and Pt LIII edges. The Fourier transforms of the Pd K and Pt LIII- edge EXAFS show clearly that the halogen atoms are forming a chemical bond only to Pt(IV) and Pt–Cl, Pt–Br, and Pt–I bond lengths are 2.34, 2.47, and 2.83Å respectively.
Reaction of Bis(4-methyl-8-quinolinolato)nitrosylpyridinecobalt(II) with Nitrogen Monoxide in Dichloromethane
Authors: Miki Eiichi , Tanaka Mikio , Mizumachi Kunihiko , Ishimori Tatsujiro 
Published: July 2006

Abstract
[Co(4mqn)2(NO)(py)] (4mqn=4-methyl-8-quinolinolate ion, C10H8NO−; py=pyridine) reacted with nitrogen monoxide in dichloromethane to produce a new compound, [NO][Co(4mqn)2(NO3)(py)], with liberation of dinitrogen oxide. The solid product was characterized by IR (including the 15N-isotopic shifts), magnetic, and MS measurements.
Reactions of α,β-Unsaturated Thiones with Diphenylcydopropenone and Diphenylcydopropenethione
Authors: Karakasa Takayuki , Takeda Satoshi , Saito Takao , Motoki Shinichi 
Published: July 2006

Abstract
2-(Arylmethylene)tetralin-1-thione and 1-aryl-3-phenyl-2-propene-1-thione (thiochalcone) reacted with diphenylcydopropenone across the =C–CO bond giving a thiophene derivative and a polysubstituted phenol with the arylketene/sulfur elimination, whereas the reaction with diphenylcydopropenethione took place at the C=S bond affording a spiro compound.
The Reaction of 1,2-Epoxyalkylsilanes with Azidotrimethylsilane. A Novel Stereoselective Synthesis of (Z)-1-Alkenyl Azides
Authors: Tomoda Shuji , Matsumoto Yuzo , Takeuchi Yoshito , Nomura Yujiro 
Published: July 2006

Abstract
The reaction of trans-1,2-epoxyalkylsilanes with azidotrimethylsilane in the presence of boron trifluoridediethyl ether complex afforded regio- and stereoselectively (Z)-1-alkenyl azides.
Selective Oxidation of 2-Bromo-m-xylene to 2-Bromo-3-methylbenzoic Acid or 2-Bromoisophthalic Acid
Authors: Miyano Sotaro , Fukushima Hiroshi , Inagawa Hideho , Hashimoto Harukichi 
Published: July 2006

Abstract
Aqueous sodium dichromate oxidation of 2-bromo-m-xylene (1) under a carbon dioxide pressure gave 2-bromoisophthalic acid (58%), while NBS-bromination of 1 followed by Sommelet oxidation to aldehyde and then potassium permanganate oxidation enabled the isolation of 2-bromo-3-methylbenzoic acid in 42% yield.
17O- and 33S-Hyperfine Splittings for Aromatic RCO\dotNSAr Radicals. Complete Evaluation of ESR Parameters
Authors: Miura Yozo , Shibata Yoshitaka , Kinoshita Masayoshi 
Published: July 2006

Abstract
17O- and 33S-Hyperfine splitting constants for aromatic RCO\dotNSAr radicals have been determined and the spin density distribution has been elucidated on the basis of the ESR parameters.
Imidazolium Dichromate. A New Reagent for the Oxidation of Alcohols to Carbonyl Compounds
Authors: Kim Sunggak , Lhim Dong Chul 
Published: July 2006

Abstract
Imidazolium dichromate, a stable yellow crystalline compound, is found to be a mild selective reagent for the oxidation of allylic and benzylic alcohols to the corresponding carbonyl compounds.
Photocatalytic Decomposition of Formic Acid on Platinized n-Type Silicon Powder in Aqueous Solution
Authors: Yoneyama Hiroshi , Matsumoto Nobuyuki , Tamura Hideo 
Published: July 2006

Abstract
Photocatalytic decomposition of aqueous formic acid was successfully achieved by using platinized n-type silicon powder as a photocatalyst under the conditions that the photocatalyst was spread on the bottom of a reaction cell.
An Electron Spin Resonance Study of 1,2,3,4-Tetrahydro-3-methyl-2,4-dioxo-1-quinazoliyloxyl Radical
Authors: Sueishi Yoshimi , Nishimura Norio 
Published: July 2006

Abstract
The ESR spectra of the title radical have been obtained in various solvents, and the assignments have been made. It is found that the solvent effects on the hyperfine coupling constants(hfc) for hydrogens on the benzene ring were small, while the nitrogen hfc (aN(1)) remarkably increased in polar solvents. The solvent dependence of the nitrogen hfc has been explained in terms of a substantial contribution of dipolar resonance structures through the N–O bond.
Ground and Excited States of Hematoporphyrin and Its Derivatives
Authors: Tanimoto Yoshifumi , Takayama Masanari , Inokuchi Ikuyo , Itoh Michiya , Miyoshi Norio , Hisazumi Haruo 
Published: July 2006

Abstract
Hematoporphyrin and two derivatives in aqueous solution undergo the molecular association to form each dimer. The association constant of 8(3)-(1-hydroxyethyl)-3(8)-vinyldeuteroporphyrin isomers is much larger than that of hematoporphyrin. No significant difference has been observed in the photophysical properties of their excited singlet and triplet states.
Synthesis of the Cyclotetrasilanes of the Type[(PhRSi)4] (R=t-Bu; t-BuCH2)
Authors: Matsumoto Hideyuki , Sakamoto Atsushi , Minemura Masahiko , Sugaya Kenji , Nagai Yoichiro 
Published: July 2006

Abstract
The cyclotetrasilanes of the type [(PhRSi)4] (R=t-Bu; t-BuCH2) were prepared by the reductive coupling of the corresponding dichlorosilanes (PhRSiCl2) with lithium.
Synthesis of 2-Methylazuleno[1,2-d]thiazoles
Authors: Fujimori Kunihide , Kitahashi Hiroyuki , Koyama Satoshi , Yamane Kameji 
Published: July 2006

Abstract
2-Methylazuleno[1,2-d]thiazoles were synthesized from diethyl 2-mercapto-1,3-azulenedicarboxylate, which was prepared by a treatment of diethyl 2-(2-methoxycarbonylethylthio)-1,3-azulenedicarboxylate with sodium ethoxide in five steps.
Synthesis of 5H-Cyclohepta[4,5]pyrrolo[2,3-b]indoles
Authors: Yamane Kameji , Yamamoto Hiroshi , Satoh Akira , Tamura Yuhji , Nozoe Tetsuo 
Published: July 2006

Abstract
The title compounds (indolo[2,3-b][1]azaazulenes) were synthesized from 2-hydrazino-1-azaazulene and cyclohexanone utilizing Fischer’s indole synthesis, followed by dehydrogenation of the N-acetylated tetrahydro precursor with DDQ. Structures of the neutral and cationic species of these compounds were discussed on the basis of the spectral data.
A Molecular Dynamical Study of the Mutual Diffusion Coefficient and Cooperative Motion in a 2-Dimensional Aqueous Solution
Authors: Kataoka Yosuke 
Published: July 2006

Abstract
Constant-temperature constant-pressure molecular dynamics simulations of a two-dimensional aqueous solution-like system are performed at many temperatures under a constant pressure. The total number of molecules in the system is 576, and the mole fraction of the solute is 0.5. The mutual diffusion coefficient, the kinetic diffusion coefficient, and the velocity correlation between different molecules are thus obtained. The reduced kinetic diffusion coefficient has a maximum at an intermediate temperature under a constant pressure. This feature is consistent with the temperature dependence of the mean-square-concentration fluctuations. The lifetime of the local structure is estimated from the cross-correlation function of displacement, which is computed from the time-averaged configurations, where the average period is several times longer than the velocity-autocorrelation time. The correlation length of the local concentration fluctuations is obtained and compared with the snapshots of the configurations at several temperatures. The dynamical properties are qualitatively in agreement with those of an alcohol–water mixture.
Preparation and Thermal Isomerization of β-Arylthio α,β-Unsaturated Thioketone Dimer
Authors: Karakasa Takayuki , Satsumabayashi Sadayoshi , Motoki Shinichi 
Published: July 2006

Abstract
β-Arylthio α,β-unsaturated thioketone dimer, 3,6-diphenyl-4-arylthio-3-[2-(arylthio)ethenyl]-3,4-dihydro-1,2-dithiin, has been prepared. Thermal isomerization of 3,4-dihydro-1,2-dithiin (aryl=phenyl) afforded 6-phenyl-2,4-bis(phenylthio)-3-thiobenzoyl-3,4-dihydro-2H-thiopyran.
Dichroism Analysis of Oriented Polyenes Produced in Poly(vinyl alcohol) Film
Authors: Maruyama Kazunori , Tanizaki Yoshié 
Published: July 2006

Abstract
Dichroic spectra of polyenes –(CH=CH)n– produced in heat-treated poly(vinyl alcohol) [PVA] film were determined for two cases; stretch (at 85 °C) after heat (120 °C), (Δ,S), and heat after stretch, (S,Δ). The dichroic ratios Rdn of component polyenes (n=2–6) were estimated by means of simulation. In both cases (Δ,S) and (S,Δ), the relation of Rdn vs. Rs (stretch ratio) kept the theoretical equation of the dichroism analysis. The relative angles among the transition moments μn (n=2–6) were in accordance with those obtained by drawings of trans-polyenes. The idea of an azimuth vector in the stretched PVA substrate was justified. The relation of Rdn(Δ,S)&gt;Rdn(S,Δ) was always observed at any Rs. This was explained by the thermal orientation-relaxation of polymer chains.
Adsorption of Tetrachloro-p-benzoquinone from Various Solvents on Metal Oxides
Authors: Esumi Kunio , Miyata Kazuaki , Waki Fumio , Meguro Kenjiro 
Published: July 2006

Abstract
Adsorption of tetrachloro-p-benzoquinone(chloranil) from basic and acidic solvents on metal oxides, such as alumina and titania was carried out to understand the acid-base interaction at the interface. The amount of chloranil adsorbed decreases with an increase of acid-base interaction between the basic solvent and chloranil and also decreases with an increase of acid-base interaction between the acidic solvent and electron donor sites of the metal oxides for both metal oxides. Furthermore, the change in concentration of chloranil radicals formed on their metal oxides by the adsorption is correlated with the acid-base interaction at the interfaces.
Phase Transition of Unsymmetric Bis(quaternary alkyl bromide) Salts of 1,4-Diazabicyclo[2.2.2]octane, C10–DABCO–Cn–Br2 (11≤n≤22)
Authors: Shimizu Jun , Imamura Kengo , Nogami Takashi , Mikawa Hiroshi 
Published: July 2006

Abstract
Phase transitions of unsymmetric bis(quaternary alkyl bromide) salts of 1,4-diazabicyclo[2.2.2]octane (DABCO)(C10–DABCO–Cn–Br2, 11≤n≤22) were studied on the basis of measurements of differential scanning calorimetries, infrared absorption spectroscopy, and bromide-anion conductivities. The DSC measurements showed two transition temperatures (Tc1 and Tc2, Tc1&gt;Tc2); this exhibits the existence of the metastable phase for the DABCO salts (C10–DABCO–Cn-Br2, 12≤n≤22). The metastable phase was converted to the stable phase within several days except for C10–DABCO–Cn–Br2 (n=12, 22). The temperature dependence of the infrared absorption spectra revealed that the band progressions due to two different alkyl chains disappeared at Tc1 and appeared again at Tc2. This shows that the trans-zigzag conformation of the alkyl chains in the low temperature phase is destroyed by the conformational change above Tc1 and then recovered again below Tc2. Abrupt increases in the bromide-anion conductivities by 100–1380 times were observed at around Tc2 for the samples annealed beforehand above Tc1. However, the virgin samples showed much broader increases in the conductivities below Tc1; no conductivity jump was observed. The conductivity increase was caused by the conformational change in the alkyl groups. The concomitant formations of the voids facilitate the bromide-anion transport.
Selective Electrolytic Cleavage of a Side-Chain Carbon–Sulfur Bond of Heterocyclic Compounds. Formation of Di-2-thienyl Disulfides and 2-Mercaptothiazoles
Authors: Fuchigami Toshio , Kandeel Zaghloul El-Shahat , Nonaka Tsutomu 
Published: July 2006

Abstract
Highly selective cleavage of a side-chain carbon–sulfur bond of thiophene and thiazole derivatives containing acyl, cyano, and ethoxycarbonyl groups was successfully performed by electroreduction to provide the corresponding disulfides and thiols respectively in excellent to good yields.
A 2H NMR Study of [Ser-3,3-2H2]- and [Ala-3,3,3-2H3]- Silk Fibroins in the Solid State. Role of Side-Chain Moiety in Stabilization of Secondary Structure
Authors: Saitô Hazime , Tabeta Ryoko , Kuzuhara Akio , Asakura Tetsuo 
Published: July 2006

Abstract
An attempt was made to prepare [Ser-3,3-2H2]- and [Ala-3,3,3-2H3]-fibroins by feeding respective amino acids Dl-[3,3-2H2]-serine (Ser) and [3,3,3-2H3]-alanine (Ala), respectively, to silkworms, Bombyx mori and Philosamia cynthia ricini together with daily artificial diet. We recorded 2H powder-pattern NMR spectra of [Ser-3,3-2H2]- and [Ala-3,3,3-2H3]-cocoons and fibroins (10–20% deuteration) by means of the quadrupole echo method. It was found that separation of the 2H quadrupole splittings is 125 and 39 kHz, respectively, for [Ser-3,3-2H2]- and [Ala-3,3,3-2H3]-cocoons and fibroins, respectively. Accordingly, it was concluded that side-cain reorientation of Ser residue is virtually frozen irrespective of differences in conformations of silk I and silk II, suggesting that the hydroxyl groups in these cases might be hydrogen-bonded to C=O or NH groups in intra or interchain. On the other hand, side-chain methyl group of Ala residue in [Ala-3,3,3-2H3]-fibroin turned out to undergo rapid three-fold rotation about the Cα–Cβ axis, as viewed from data of the quadrupole splittings.
Temperature Effect on the Association of Aqueous Europium and Sulfate Ions from Luminescence Decay Measurement
Authors: Tanaka Fujio , Kawasaki Yoshiko , Yamashita Shigeru 
Published: July 2006

Abstract
The luminescence lifetime for Eu2(SO4)3 and EuCl3 in H2O and D2O has been measured at 0.01 and 0.001 mol dm−3 of Eu3+ and at various temperatures from 5 to 45 °C. The average number of water molecules coordinated to Eu3+ ion, q, is evaluated from the difference of the luminescence decay constants in the H2O and D2O solutions. By using the q value of 8.3 for aquaeuropium(III) ion in EuCl3 solutions, q values for Eu2(SO4)3 solutions were determined as a function of concentration and temperature. The average number of water molecules released from the primary hydration sphere by the inner-sphere complexation between Eu3+ and SO42− ions is given as Δq=8.3–q, and Δq value increases with concentration and temperature. From the values of Δq and the known equilibrium constants on the overall complexation, it is revealed that for both the unis(sulfato) and bis(sulfato) complexation the ratio of inner-sphere complex to outer-sphere complex increases with temperature and that about one water molecule is released from the inner hydration sphere surrounding Eu3+ ion on the formation of an inner-sphere unis(sulfato) complex. The coordination state of the unis(sulfato) complex and the thermodynamic quantities for the equilibrium between outer- and inner-sphere complexes are discussed.
Electrochemical Study on the Initial Stages of the Electropolymerization of 1-Pyrenamine in Acetonitrile
Authors: Ohsaka Takeo , Hirabayashi Kazuhiko , Oyama Noboru 
Published: July 2006

Abstract
The kinetic study of the mechanism for the reaction of the initial stages of the electropolymerization of 1-pyrenamine (PA) in an acetonitrile solution was carried out by cyclic voltammetry (CV) and double potential-step chronoamperometry (DPSCA). The experiments were conducted at various time windows (i.e., at various scan rates of CV and various potential-step widths of DPSCA) and under the conditions of the presence or absence of the basic or acidic additives (pyridine, 2,6-lutidine, trifluoroacetic acid). As a result, it was found that the mechanism of the reaction of the initial stages of the electropolymerization of PA is an “ECE” mechanism, and that the chemical reaction interposed between successive electron transfers is considered as the radical–radical coupling reaction rather than the radical–parent monomer coupling reaction. The second-order rate constant for the radical–radical coupling reaction was estimated to be (1.0±0.8)×105 M−1 s−1 (1 M=1 mol dm−3). The cyclic voltammetric responses for the oxidation of PA were varied by the presence or absence of the basic or acidic additives. This can be explained considering the basicity of the additives and their influences in the deprotonation reactions following the heterogeneous electron transfer step.
Reflection Spectra of (DBTTF)4·(BF4)2·EtOH Complex
Authors: Tanaka Masashi 
Published: July 2006

Abstract
The polarized reflection spectra of the crystal of (DBTTF)4·(BF4)2·EtOH complex were measured and the optical parameters were determined by the simulation of the observed reflection spectra. The theoretical analysis of the observed spectra shows that the electronic structure of DBTTF cation molecules is typical of the island type configuration. The 4000 and 11500 cm−1 bands polarized parallel to the stacking axis were assigned to the CT2 and CT1 bands, and the parameters U and t of the Hubbard Hamiltonian were estimated to be (U=8950 cm−1 and t=1250 cm−1.
Isotachophoretic Analysis of Quaternary Ammonium Ions by Using α-Cyclodextrin as Complex-Forming Agent
Authors: Tazaki Masato , Hayashita Takashi , Fujino Yasumitsu , Takagi Makoto 
Published: July 2006

Abstract
The isotachophoretic behavior of aromatic nucleus-containing quaternary ammonium ions was studied in the presence of a neutral ligand, α-cyclodextrin. Due to the interaction of cyclodextrin with the hydrophobic aromatic nucleus, isomeric ammonium ions containing, e.g., an o-, m-, or p-disubstituted benzene ring, were satisfactorily separated. In the absence of cyclodextrin, the separation of the isomers was poor. A theoretical approach was also used in order to evaluate the binding equilibrium constant (K) between the analyte ion and α-cyclodextrin through an isotachophoretic measurement. The binding constants (logK) with (o-, m-, and p-methylbenzyl)trimethylammonium ions were found to be 0.8, 1.1, and 1.6, respectively.
Synthesis of Copper(II)–Dithiooxamide Complex in Zirconium Phosphate
Authors: Hasegawa Yoshitsugu , Kamikawaji Midori , Sasaki Kaname 
Published: July 2006

Abstract
Copper(II)–dithiooxamide (rubeanic acid) complex was synthesized in the interlayer region of zirconium phosphate. The product, called ZP–CuLra, was chracterized by chemical analysis, thermal analysis, infrared spectroscopy, and X-ray diffractometry. The chemical composition of ZP–CuLra was represented as ZrCu(H2NCS)2(PO4)2·H2O or ZrCu(HNCS)2(HPO4)2·H2O. The interlayer distance of ZP–CuLra was found to be 9.0 Å. By analogy with Cu(II)–rubeanic acid complex prepared in a solution, a structural model of ZP–CuLra was proposed.
Mechanism of Chiral Recognition of Octahedral Metal Complexes Effected by Bis(μ-d-tartrato)-diantimonate(III) Anion in Solution. I. Association Models and Their Application to Some [Co(N)6]3+-Type Complexes
Authors: Miyoshi Katsuhiko , Izumoto Shinji , Yoneda Hayami 
Published: July 2006

Abstract
An association model has been proposed which accounts for how bis(μ-d-tartrato)-diantimonate(III) anion, [Sb2(d-tart)2]2− ion recognizes the chirality of [Co(en)3]3+ (en=ethylenediamine) and some related cation complexes in solution. In this model, two oxygen atoms of the chiral anion, i.e., the carboxylic oxygen atom (coordinated to the Sb atom) of one d-tartrate moiety and the alcoholic oxygen atom (coordinated to the same Sb atom) of the other d-tartrate moiety, are hydrogen-bonded to the two amine protons in [Co(en)3]3+ which are directed along either the C3 or C2 axis. When these hydrogen bonds are formed along the C3 axis (C3 association), [Sb2(d-tart)2]2− ion forms a more favorable ion pair with Λ-[Co(en)3]3+, whereas it does with Δ-[Co(en)3]3+ if the two amine protons directed along the C2 axis are utilized for hydrogen bonding to it (C2 association). This model is successfully applied to the interpretation of chromatographic behavior of some [Co(N)6]3+-type complexes as well as of their related complexes with amine or phosphine ligands.
Preparation, Characterization, and Some Reactions of Cationic Hydrido Carboxylato Complexes of Molybdenum(IV), [MoH2(O2CR)(dppe)2]+
Authors: Ito Takashi , Takahashi Akihiko , Tamura Shigeyoshi 
Published: July 2006

Abstract
Cationic carboxylatodihydridomolybdenum(IV) complexes, [MoH2(O2CR)(dppe)2]BPh4 (R=CH3, C2H5, CH2=CH, and CH2=C(CH3); dppe=Ph2PCH2CH2PPh2), were prepared by treating [MoH4(dppe)2] with RCOOH followed by anion exchange with NaBPh4, and characterized spectroscopically. A possible pathway of the reaction is discussed on the basis of the experiment using CH3COOD. Light irradiation of the EtOH solution of the cationic acetato complex in the presence and absence of CO afforded the known cis-[Mo(CO)2(dppe)2] and the neutral hydridoacetato complex, [MoH(O2CCH3)(dppe)2], respectively.