bluuebunny/crossref_metadata_2025 huggingface dataset:
Photochemical Cis–Trans Isomerization of 5-Styryl-1,3-dimethyluracil
Authors: Shin Eun Ju , An Beom Shu , Shim Sang Chul
Published: July 2006

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

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

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

[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

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

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

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

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

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

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

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

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

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

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

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

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

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

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)>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

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

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>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

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

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

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

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

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

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

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

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

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.
Synthesis, and Crystal and Molecular Structure of Bis(N-methyl-formamide)tetrakis(thiocyanato)cobalt(II)mercury(II), CoHg(SCN)4(HCONHCH3)2
Authors: Kinoshita Hisashi , Ouchi Akira
Published: July 2006

The title complex was synthesized and its crystal and molecular structure were determined by the single-crystal X-ray diffraction technique. The crystal is orthorhombic with a space group P21nb, a=14.953(4), b=15.955(4), c=7.6838(9) Å. The crystal was solvent by means of the heavy-atom method and the final R value was 0.059. The mercury atom is in the tetrahedral geometry, coordinated with four sulfur atoms of the thiocyanate (SCN) ions, and the cobalt atoms is in the octahedral geometry, coordinated with four nitrogen atoms of SCN ion and two oxygen atoms of N-methylformamide which occupy the cis positions. Each pair of different kinds of metal atoms is bridged by an SCN ion and are in a three-dimensional network. Twenty-four membered rings of Co3Hg3(SCN)6, where the metal atoms are arranged hexagonally in a chair-form, are condensed two-dimensionally approximately parallel to the (100) plane. All mercury atoms on one plane are bridged by SCN ions to the cobalt atoms of the polymeric plane next to the [100] direction, while the cobalt atoms are linked by SCN ions to the mercury atoms on the next plane of the opposite side. The mfa ligands take their positions in vacancy of the network.
Selective Modification of the Two Type I Copper Sites in Human and Bovine Ceruloplasmin with the Action of Azide and l-Cysteine
Authors: Sakurai Takeshi , Nakahara Akitsugu
Published: July 2006

The two type I copper sites of human and bovine ceruloplasmin (CP) were indirectly modified through the binding of N3− to types II and III copper ions. Based on the fact that the activities of CP’s modified with N3− were 85 and 47% for human and bovine CP, respectively, it was disclosed that the electronic and steric states of the “fast” type I Cu or “CuA” which is coupled with the types II and III copper ions was changed reversibly, whilst the “slow” type I Cu or “CuB” which is not coupled with the types II and III copper ions was changed to a type II copper ion and/or irreversibly reduced. On the other hand, the reaction of a limited amount of l-cysteine with CP gave the absorption and electron paramagnetic resonance spectra of CP whose CuB was selectively reduced. The treatment of this CP with 4,7-diphenyl-2,9-dimethyl-1,10-phenanthroline-4′,4″-disulfonate did not result in the selective removal of CuB.
Inversion at Selenium in the Bis(β-diketonato)[2-(methylseleno)-ethylamine]cobalt(III) Ion
Authors: Nakajima Kiyohiko , Kojima Masaaki , Fujita Junnosuke
Published: July 2006

The selenide (selenoether) complexes, [Co(β-dik)2(CH3SeCH2CH2NH2)]+ (β-dik: acac=2,4-pentanedionate, Clacac=3-chloro-2,4-pentanedionate, Meacac=3-methyl-2,4-pentanedionate, and dbme=1,3-diphenyl-1,3-propanedionate) were prepared and separated into two racemic pairs of the diastereomers (Δ(R)Λ(S) and Δ(S)Λ(R) isomers). The complexes in solution epimerize by inversion at the selenium atom, and the rates were followed by high-performance liquid chromatography in the temperature range of 30.3–55.0 °C in 0.05 mol dm−3 Na2SO4 (acac, Clacac, and Meacac complexes) or in methanol (dbme complex). The ΔG25°C\eweq values for inversion of [Co(β-dik)2(CH3SeCH2CH2NH2)]+ decrease in the order β-dik=Clacac(108)>acac(106)>dbme(104)>Meacac(100 kJ mol−1), and the decrease in ΔG25°C\eweq comes mainly from a decrease in ΔH\eweq. The effect of substituents is electronic and the Hammett relationship was found to hold for the inversion rates of the acac, Clacac, and Meacac complexes.
The Crystal and Molecular Structure of 6-Bromo[2.2]paracyclo(4,8)[2. 2]metaparacyclophane
Authors: Koizumi Yosuke , Horita Hisanori , Otsubo Tetsuo , Kasai Nobutami , Misumi Soichi
Published: July 2006

The molecular structure of the title compound has been determined by means of X-ray diffraction. C26H25Br, M 417.4, orthorhombic, space group P212121, a=12.713(1), b=14.998(1), c=10.156(1) Å, V=1936.3(1) Å3, Dm=1.43 g cm−3, Dc=1.432 g cm−3 for Z=4.
Synthesis and Biological Activities of Acetylenic Fatty Acids and Their Esters
Authors: Nakatani Munehiro , Fukunaga Yuji , Haraguchi Hiroyuki , Taniguchi Makoto , Hase Tsunao
Published: July 2006

Eight terminal acetylenic fatty acids from 5-hexynoic to 12-tridecynoic acids and their methyl, ethyl, and isopropyl esters were synthesized via o-nitrophenyl selenides. These acids and esters all showed inhibitory effect on lettuce seed germination and seedling growth. The effect was dependent on the number of carbon atoms in acetylenic chain. 8-Nonynoic acid showed potent activity, and its methyl ester was the most effective among the test compounds. In addition, the acids showed antifungal activity which increased as the number of carbon atoms increased.
The Ability of the Proline Residue to Promote Successive-Intramolecular Hydrogen Bonds in Oligopeptides
Authors: Narita Mitsuaki , Isokawa Shizuko , Doi Masamitsu , Wakita Ryuhei
Published: July 2006

In order to investigate the ability of the Pro residue to promote helical folding in oligopeptides, the IR spectroscopic conformational study of the oligo(Leu)s containing the Pro residue was performed in dichloromethane. Their IR difference spectra suggested the occurrence of successive-intramolecular hydrogen bonds just like incipient α-helical structures formed by one, two, three, and so forth i→i–4 hydrogenbonding patterns, alluding to the ability of the Pro residue to promote helical folding in the peptides. However, the intensities of hydrogen-bonded absorption bands in the amide A region of each peptide strongly suggested that conformations of the peptides investigated were also contributed by other intramolecularly hydrogen-bonded folded structures, which had lower absorption coefficients. The initiation mechanism of successive-intramolecular hydrogen bonding in the peptides is apparently attributed to the disturbance of the β-sheet formation by the rotation of the tertiary peptide bond plane (Leu–Pro), that is, the restriction of the values of the backbone dihedral angles φ and ψ of the Pro residue due to the low flexibility of the pyrrolidine ring.
A Novel and Highly Efficient Asymmetric Synthesis of Optically Active Anthracyclinones
Authors: Suzuki Michiyo , Kimura Yoshikazu , Terashima Shiro
Published: July 2006

The bromolactonization of the optically active acetals derived from 2-acetyl-5,8-dimethoxy-3,4-dihydronaphthalene and (R,R)-N,N:N′,N′-tetraalkyltartaramide was found to proceed highly diastereoselectively, giving mixtures of the seven-membered bromo lactones and the bromohydrins. The predominantly produced bromo lactones could be effectively converted to (R)-2-acetyl-5,8-dimethoxy-1,2,3,4-tetrahydro-2-naphthol, the AB ring synthon of optically active 11-hydroxyanthracyclinones, >95% ee, in one pot reaction. Application of the explored synthetic scheme to 2-acetyl-5,12-dimethoxy- and 2-acetyl-5-methoxy-3,4-dihydro-6,11-naphthacenedione similarly gave (R)-2-acetyl-2,5,12-trihydroxy- and (R)-2-acetyl-2,5-dihydroxy-1,2,3,4-tetrahydro-6,11-naphthacenedione, the advanced key synthetic intermediates of optically active 4-demethoxy- and 11-deoxy-4-demethoxyanthracyclinones, 94% ee and >99% ee, respectively, by way of mixtures of the seven- and six-membered bromo lactones.
Photocatalytic Behavior of Di- and Triferrocenylbenzenes on Reduction of Methyl Viologen and Photochemical Hydrogen Evolution from Methanol under Visible Light
Authors: Akiyama Takeo , Kawaharada Yukihiko , Kondo Akira , Kajitani Masatsugu , Endo Akira , Shimizu Kunio , Sugimori Akira
Published: July 2006

1,4- and 1,3-Diferrocenylbenzenes (1a and 1b), 1,2,4- and 1,3,5-triferrocenylbenzenes (1c and 1d) can act as photocatalysts for photochemical hydrogen evolution from methanol in the 1–methyl viologen MV2+–triethanolamine-colloidal Pt-catalyst system under the irradiation with visible light. The order of the photocatalytic activities of 1 is 1d>1c>1a>1b. The catalytic activities of 1 can be correlated to the E1⁄2 values. 1 acts as a photocatalyst in the wavelength region of λ>440 nm, whereas it acts as a quencher for the formation of MV\underset.+ in the wavelength region of λ<440 nm. The highest quantum yield of the formation of MV\underset.+ catalyzed by 1(1d: QMV\underset.+=0.028, at 480 nm) was obtained in the wavelength region where the intensity of the solar light is the largest.
Selenium and Tellurium Tetrachlorides as Reagents for the Conversion of Alcohols to Alkyl Chlorides and Tellurium Tetrachloride as a Lewis Acid Catalyst for Aromatic Alkylation
Authors: Yamauchi Takayoshi , Hattori Kaneaki , Mizutaki Shoichi , Tamaki Kentaro , Uemura Sakae
Published: July 2006

Selenium tetrachloride(SeCl4) reacts smoothly with alcohols in various nonpolar solvents to give the corresponding alkyl chlorides in 44–97% yield. Similar reaction also proceeds with tellurium tetrachloride (TeCl4), while the treatment of benzyl, 1-phenylethyl, and t-butyl alcohols with TeCl4 in aromatic solvents results in a high yield formation of alkylated aromatics instead of alkyl chlorides. Such Friedel-Crafts aromatic alkylation hardly occurs in the SeCl4 case. The chlorinating species is not chlorine which might be evolved by dissociation of SeCl4 or TeCl4, but the metal chloride itself. The conversion of optically active (R)-(+)-1-phenylethanol to 1-phenylethyl chloride proceeds with nearly complete racemization.
Enzymatic Esterolysis of Polymers Containing 2-Biphenylyl Ester Bonds in Side Chains
Authors: Ishikawa Tomomichi , Otsuki Makoto , Iwatsuki Toshiaki
Published: July 2006

The preparation and α-chymotrypsin-catalyzed esterolysis of polymeric substrates anchoring fungicidal biphenyl-2-ol are described. In order to obtain information regarding the influence of one type of polymeric backbone and the distance between a cleavable bond and a polymer main chain, poly(2-biphenylyl acrylate), poly(2-biphenylyl methacrylate), and poly(methacryloylamino acid 2-biphenylyl ester)s were studied. The esterolysis were evaluated by means of Michaelis constant Km and the catalytic reaction rate constant kcat. Poly(2-biphenylyl methacrylate) was a more suitable substrate than poly(2-biphenylyl acrylate). Poly[6-(methacryloylamino)hexanoic acid 2-biphenylyl ester] was the most suitable substrate in a series of polymers containing amino acid side chains with 2-biphenylyl ester terminal groups. The release rate of biphenyl-2-ol could also be controlled by using copolymers with an appropriate comonomer.
Preparation and Characterization of a Resin-Supported Palladium Catalyst
Authors: Uematsu Takayoshi , Umino Masao , Shimazu Shogo , Miura Masatoshi , Hashimoto Hidehisa
Published: July 2006

The process of the ligand release and the reduction of [Pd(NH3)4]-form sulfonic resin has been studied by chemical analysis, X-ray photoelectron spectroscopy and adsorption techniques. The removal of ammonia ligands remarkably increased with hydrogen treatment above 353 K, and was complete at around 393 K. It is suggested that the released ammonia partly transfers to –SO3− groups to form –SO3NH4 groups as the reduction proceeds. The dispersion of the metal particles prepared by hydrogen reduction ranged from 0.11 to 0.31 depending on the loading concentration of the palladium cation. The metal particles are considered to be entrapped in the pores of the resin. The formation of cationic palladium sites by the low temperature reduction is also suggested.
Catalytic Effects of MoCl3- and NiCl2-Containing Molten Salts for Hydroliquefaction of Morwell Brown and Taiheiyo Subbituminous Coals
Authors: Song Chunshan , Nomura Masakatsu
Published: July 2006

The catalytic effects of MoCl3–LiCl–KCl and NiCl2–LiCl–KCl molten salts were studied for the hydroliquefaction of Morwell brown and Taiheiyo subbituminous coals at 400 °C for 1 h in a batch reactor with an initial hydrogen pressure of 9.8 MPa. The conversion to pyridine-soluble materials and the yield of hexane-soluble materials (HS) with the MoCl3 catalyst were 82 and 42% for Morwell coal, and 84 and 61% for Taiheiyo coal, respectively. The conversion and HS yield with the NiCl2 catalyst were 87 and 43% for Morwell coal, and 82 and 56% for Taiheiyo coal, respectively. The HS yield of the catalytic runs was about 2.6–3.2 times higher than that of noncatalytic runs. This finding established the effectiveness of the two new catalysts for the hydroliquefaction of brown and subbituminous coals. Detailed analyses of the reaction products have revealed that these catalysts promoted a depolymerization of the coals and strongly catalyzed the hydrocracking of polynuclear aromatic structures of heavy products into hydroaromatic and aromatic structures with smaller ring sizes. Most of these smaller hydroaromatic and aromatic structures did not undergo much further ring-opening reactions. This accounts for the high HS selectivity of the catalysts.
Polystyrene Resin-Supported Aluminium Copper(I) Chloride as Selective Ethylene Adsorbent
Authors: Hirai Hidefumi , Nakamura Masahiro , Hara Susumu , Komiyama Makoto
Published: July 2006

Solid adsorbents for ethylene are prepared by stirring copper(I) chloride, aluminium chloride, and a macroreticular type polystyrene resin in carbon disulfide, followed by removal of the liquid phase. The adsorbents effectively adsorb ethylene at 20 °C under 1 atm, and exhibit no measurable adsorptions of nitrogen, hydrogen, and methane.
High Stereoselectivity of Tris[4-(l-menthyloxy)-1-(p-tolyl)-1,3-butandionato]lanthanoid(III)
Authors: Okawa Hisashi , Nakamura Michio , Shuin Y\={u}ko , Kida Sigeo
Published: July 2006

Tris[4-(l-menthyloxy)-1-(p-tolyl)-1,3-butanedionato]lanthanoid(III), [Ln(l-moba-Me)3](Ln=La, Pr, Nd, Eu, Gd, Dy, Ho, Er, Tm), showed a high stereoselectivity effected by intramolecular noncovalent interactions, giving rise to the cis-Δ form.
Molecular Structure of a Reductive Dimer of Pulegone
Authors: Kikuchi Mitsuko , Taira Zenei
Published: July 2006

The molecular structure of “bishydropulegone,” a reductive dimer of pulegone, was determined as (1R,3′aR,4R,6′R,7′aS)-7-′a-hydroxy-2′,2′,3′,3′,4,6′-hexamethylspiro[cyclohexane-1,1′-indan]-2-one by X-ray crystallographic analysis.
Interaction of Iron(III) Chloride with d-Fructose in an Acidic Solution
Authors: Araki Koji , Shiraishi Shinsaku
Published: July 2006

Complex formation between Fe(III) and d-fructose in an acidic solution was studied by electronic and CD spectroscopy, and the role of the complex in the photochemically-induced oxidation of d-fructose by Fe(III) was discussed.
A Kinetic Study of the Thermal Conversion of 1′,3′,3′-Trimethylspiro[2H-1-benzopyran-2,2′-indoline]-8-carboxylic Acid
Authors: Sueishi Yoshimi , Ohcho Masanobu , Yamamoto Shunzo , Nishimura Norio
Published: July 2006

The rate of the thermal conversion of 1′,3′,3′-trimethylspiro[2H-1-benzopyran-2,2′-indoline]-8-carboxylic acid (8-COOH-SP) from its spiro form to its merocyanine form has been measured in several solvents at high pressures. Small solvent- and pressure-dependencies of the rate were observed. These results suggest that the electronic structure of the transition state of this reaction is nonpolar and that it is similar to that previously observed for the thermal conversion of so-called 6-nitrospiropyran from its merocyanine form to its spiro form.
Orthogonal Approximation and Classification of Molecules for Zero-Point Energy Shifts Due to H/D Isotope Substitutions
Authors: Oi Takao , Ishida Takanobu
Published: July 2006

Dozens of hydrogenous molecules have been classified for the approximation of the H/D isotope shifts in zero-point energies. The classification, based on their molecular structures, has yielded relative approximation errors of better than one percent with a few predictable exceptions. A further refinement of the classification has been suggested.
Photolytic Formation of a Uranium(V)–DMSO Complex and the Paramagnetic Shift of DMSO by Uranium(V)
Authors: Fukutomi Hiroshi , Harazono Toshie
Published: July 2006

A U(V)-DMSO complex (DMSO=dimethyl sulfoxide) formed by photoreduction of [UO2(dmso)5]2+ was stable in acid-free DMSO and a small quantum yield of U(V) was attributed to the difficulty in electron transfer from ligands to U(VI). The paramagnetic shift of DMSO by U(V) indicates that only the pseudo-contact shift is induced.
Formation of 2-Substituted 1,3-Diphenylindenes by an N-Bromosuccinimide Prompted Dehydrocyclization of 2-Substituted 1,3,3-Triphenyl-1-propenes
Authors: Yamamura Kimiaki , Miyake Hideyoshi , Sera Akira
Published: July 2006

The reactions of a series of 2-substituted 1,3,3-triphenyl-1-propenes with N-bromosuccinimide (NBS) afforded the corresponding 2-substituted 1,3-diphenylindenes in moderate yields. A reaction mechanism involving a novel free-radical intramolecular ring-closure reaction is suggested.
Carbon Dioxide-Promoted Telomerization of 1,2- and 1,3-Dienes with Benzenesulfinate Catalyzed by Palladium(0)\eweq
Authors: Inoue Yoshio , Hashimoto Harukichi
Published: July 2006

The telomerization of 1,2- and 1,3-dienes with benzenesulfinate dihydrate catalyzed by palladium(0) has been promoted by the presence of carbon dioxide.
Pressure and Temperature Effects on the Excess Conductance of the Hydroxide Ion in Water
Authors: Ueno Masakatsu , Sakata Yasushi , Tsuchihashi Noriaki , Shimizu Kiyoshi
Published: July 2006

The limiting molar conductances, Λ°, of sodium hydroxide were determined at 15, 25, and 40 °C as a function of the pressure up to 1500 kgf cm−2 (1 kgf cm−2=0.9807×105 Pa) from the conductances measured in a dilute concentration range (1×10−3–2×10−2M, 1 M=1 mol dm−3). The excess conductances at an infinite dilution, λ°E, of the hydroxide ion, as estimated by [λ°E(OH−)=Λ°(NaOH)−Λ°(NaCl)], were found to increase with an increase in the pressure and temperature, as well as those of the oxonium ion, λ°E(H3O+). However, there was a significant difference in the magnitude of λ°E, itself, and a slight difference in the magnitude of the pressure and temperature dependences of λ°E between hydroxide and oxonium ions. These results may be related to a difference between the proton-jump mechanisms of the hydroxide and oxonium ions.
Valence Coordinate Contributions to Zero-Point Energy Shifts Due to Hydrogen Isotope Substitutions
Authors: Oi Takao , Ishida Takanobu
Published: July 2006

The orthogonal approximation method for the zero-point energy (ZPE) developed previously has been applied to analyze the shifts in the ZPE, δ(ZPE), due to monodeuterium substitutions in methane, ethylene, ethane and benzene in terms of elements of F and G matrices. The δ(ZPE) can be expressed with a reasonable precision as a sum of contributions of individual valence coordinates and correction terms consisting of the first-order interactions between the coordinates. A further refinement in the precision is achieved by a set of small number of second-order terms, which can be estimated by a simple procedure.
The Regulation of Emulsion Polymerization of Styrene with Anionic–Nonionic Emulsifier Mixtures
Authors: Kato Kazufumi , Kondo Harumi , Esumi Kunio , Meguro Kenjiro
Published: July 2006

The emulsion polymerization of styrene was carried out in the presence of mixtures of a nonionic surfactant (poly(oxyethylene) hexadecyl ether; BC-20) and an anionic surfactant (sodium dodecyl sulfate; SDS or lithium perfluorooctanesulfonate; LiFOS). The polymerization rate changed with the hydrophile-lypophile balance (HLB) of the BC-n series. The polymerization rate considerably increased on the addition of SDS or LiFOS. However, the further addition of LiFOS caused a gradual depression of the polymerization rate. The polymerization rate was not dependent on the amount of styrene solubilized in the mixed emulsifier solution. The particle sizes decreased remarkably on adding SDS. The molecular weights of polystyrene in latex synthesized in mixed emulsifier solutions were larger than those in a single emulsifier solution. The molecular-weight distributions of polystyrene formed in mixed emulsifier solutions were wider than those of polystyrene formed in a single emulsifier solution. These results may be attributed to properties such as the composition and the charge density of the mixed micelles, and to the solubilized amount of styrene monomer in the mixed nonionic-anionic emulsifier solutions.
Stopped-Flow Small-Angle X-Ray Scattering Study on the Acid-Denaturation of Taka-Amylase A
Authors: Hozaki Tatsuya , Kato Mitsunori , Sato Mamoru , Tanaka Nobuo , Morimoto Yukio , Hata Yasuo , Katsube Yukiteru , Kasai Nobutami
Published: July 2006

A stopped-flow small-angle X-ray scattering method was applied to study the structural change of Taka-amylase A by acid-denaturation. The structural change could be described by two successive steps. The first step is described by a change in the eccentricity of a prolate ellipsoid from 2.0 to 2.4; this was estimated by a comparison between the observed scattering profile and the theoretical scattering function of the prolate ellipsoid. The second step supposes that the X-ray scatterer in a solution comprises two kinds of particles with large and small radii of gyration. The X-ray scatterer with a large radius expands with time. By contrast, the radius of gyration of the small scatterer corresponds to that of a native Taka-amylase A monomer and it remains unchanged. These facts imply that in the denaturation of Taka-amylase A the molecule is prolonged by a partial unfolding of the polypeptide chain and then aggregates with each other.
The Arrhenius Parameters for the Reactions of N(24S3⁄2) with Halogen Molecules
Authors: Umemoto Hironobu , Uchida Teruo , Nakagawa Seiko , Tsunashima Shigeru , Sato Shin
Published: July 2006

The temperature dependence of the rate constants for the reactions of ground-state atomic nitrogen with halogens were measured by means of a pulse radiolysis-resonance absorption technique. The rate constants for iodine and bromine were well expressed by the following Arrhenius expressions below 410 K: k(N+I2)=1.1×106 exp(−1170/T); k(N+Br2)=1.1×105 exp(−1490/T), in units of m3 mol−1 s−1. The rate constant for the reaction with chlorine was found to be 1.1×103 m3 mol−1 s−1 at 411 K. Below this temperature, the rate constants for N+Cl2 were too small to be measured. The preexponential factors for the I2 and Br2 reactions were found to be much smaller than the semiempirically calculated ones. These small preexponential factors suggest that the reactions between N(4S) and halogens proceed via nonadiabatic routes.
The Epitaxial Growth of the Methyl Triacontanoate Crystal
Authors: Ueda Yasukiyo
Published: July 2006

Methyl triacontanoate (MT) was deposited on the cleavage face of the KCl crystal in vacuo. The MT film was composed of V-shaped crystals growing along two directions crossing at 32°, and these crystals intersected at right angles to each other. The bisectional direction of the V-shaped crystals corresponds to the [110] direction of the substrate crystal. The electron-diffraction pattern from the film consisted of the reflection spots corresponding to the (hkl)s planes of the subcell and the series of 00l reflections in the small-angle region. The crystal structure of the deposited MT crystal was monoclinic in form. The (110) plane of the MT crystal was oriented parallel to the substrate (001) plane, and its c-axis was parallel to the [110] direction of the substrate crystal. The V-shaped crystal was explained by the molecular arrangement in the epitaxial growing crystals. When the substrate was kept at a higher temperature than the melting point of MT, the deposit coagulated to disk-like crystals whose c-axis was perpendicular to the substrate.
How Do Proton Chemical Shifts Reflect Aromaticity ? Graph Theory of the Secondary Magnetic Field Due to Ring Currents
Authors: Aihara Jun-ichi
Published: July 2006

A secular determinant for a polycyclic conjugated molecule, combined with a test dipole, is definable as a function of the applied magnetic field. It was found that this determinant can be expanded graph-theoretically into a characteristic polynomial. A secondary magnetic field is brought about by so-called ring currents. A new formula for evaluating the secondary field was derived by applying Newton’s method to this polynomial. This formula indicates that the secondary field at any point in the molecular plane is given exactly as a sum of the contributions of all π-electron circuits. The contribution of each π-electron circuit is expressible in terms of a pure geometric factor and an aromatic stabilization energy assigned to the circuit. The secondary field and then the proton chemical shifts can thus be related to aromaticities of individual π-electron circuits. Magnetotropism of most polycyclic conjugated molecules can be rationalized in this manner. π-Electron circuits which share the conjugated atom nearest to a given proton dominate the chemical shift. In general, a peripheral π-electron circuit contributes modestly to the overall thermodynamic stability of a molecule, but contributes much to the secondary fields at attached protons.
A Model of Crystal Defects in Calcite by Sodium and Potassium Uptake
Authors: Ishikawa Masamichi , Ichikuni Masami
Published: July 2006

Crystal defects in calcite containing Na and K ions were investigated by means of a model based on statistical thermodynamics and measurements of thermoelectric power. The varying amount of Na and K ions in the crystal was interpreted on an assumption of ideal solution of the ions as Ca1−x−y\squarex+y[Na2x, K2y]CO3, where \square and [ ] means Ca-vacancy and interstitial ion, respectively. In the model, the excess charge of Na and K ions is balanced with Ca-vacancy to form interstitial-vacancy pairs ([Na, K]2\square). Measurements of thermoelectric power in calcite showed the cationic transport which resulted from Na and K interstitials and/or Ca-vacancies. From the ideal mixing of Na and K ions at interstitial sites, the K/Na molar ratio in calcite was correlated with that in aqueous solution at 20 °C and pH 8.5 by the formula,

\fracKSNaS=0.20\fracKLNaL,

where S and L refer to solid- and aqueous-phase, respectively.