bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Theoretical Approach to the Dielectric Relaxation of Alcohol Solutions
Authors: Minami Ryuichi , Itoh Koichi , Sato Hiroshi , Takahashi Hiroaki , Higasi Keniti 
Published: July 2006

Abstract
The dielectric relaxation mechanism of primary alcohols in solutions of various solvents with and without a hydrogen-bonding capacity was theoretically studied using the concept of the chemical equilibrium between hydrogen-bonded chain multimers and that between the multimers and solvents. The dipole-inversion processes originating from the successive rotation of the hydroxyl groups of the hydrogen-bonded multimers were considered to play the dominant role in the dielectric relaxation of alcohol solutions. By applying the one-dimensional random-walk process to the dipole inversion, we estimated the effect of dilution upon the dielectric relaxation times of primary alcohol in solution. The results of our calculation appear to explain the experimental data.
A Sensitive Atomic Absorption Spectrometric Method for Copper Employing the Direct Introduction of Chelating Resin into a Carbon Tube Atomizer
Authors: Isozaki Akinori , Soeda Naoki , Utsumi Satori 
Published: July 2006

Abstract
A new and simple method for the determination of ppb levels of copper by electrothermal atomic absorption spectrometry was established. The main feature of the proposed method is that chelating resin, a preconcentration agent for copper, is introduced directly as a “resin-suspension” into the carbon tube atomizer without drying and weighing of the resin. To a 250 cm3 sample solution containing up to 1.0 μg of copper, 0.10 g of chelating resin (below 400 mesh) is added, and the mixture is stirred for about 20 min. After the separation of the resin from the aqueous phase through a membrane filter, 5.0 cm3 of resin-suspension is prepared by adding water to the resin. Then, 10 μdm3 (resin: 0.2 mg) of the suspension is introduced into an atomizer, and the copper peak-height is measured under the optimum operating conditions. The calibration graph was linear over the concentration range from 0.1 ppb to 4.0 ppb of copper. The relative standard deviation was 2.3% from 10 repeated measurements; a mean value of 1.08 ppb copper was obtained for a sea water sample.
Structural Interpretation of Plasma-polymerized Tetrafluoroethylene
Authors: Hozumi Keiichiro , Kitamura Keisuke , Kitade Tatsuya 
Published: July 2006

Abstract
Structural interpretation of plasma-polymerized tetrafluoroethylene produced in a glow discharge chamber is given by referring to 19F-NMR and IR spectroscopy, elemental analysis, and number-average molecular weight determination. The polymer is hardly soluble in the usual organic solvents because of its highly branched structure, making NMR spectroscopy and molecular weight determination impossible. However, the polymer is soluble in 1,2-dibromo-1,1,2,2-tetrafluoroethane and the following structural interpretation could be obtained. The number-average molecular weight is 3600 for the majority of the polymer, consisting of 96 carbon and 129 fluorine atoms within a unit molecule. The IR spectrum shows evidence of some C=C groups and the 19F-NMR spectrum a highly branched and cross-linked structure in which a large number of quaternary carbons are involved in the polymer matrix as compared with CF2 and CF carbons. The plasma-polymerized tetrafluoroethylene has been characterized in a somewhat different way from the plasma-polymerized ethylene, involving a small number of quaternary carbons.
Formose Reactions. XIV. A Selective Formose Reaction in the Presence of a Slight Amount of Calcium Ions
Authors: Shigemasa Yoshihiro , Taji Tsuyoshi , Waki Eiichi , Nakashima Ruka 
Published: July 2006

Abstract
It was found that a formose reaction in the presence of small amounts of calcium and d-fructose gave rise to three products, 2-(hydroxymethyl)glycerol, 3-(hydroxymethyl)pentitol, and 2,4-bis(hydroxymethyl)pentitol, with a high selectivity. Various factors affecting the selectivity were also discussed: [Ca], pH, [d-fructose], the reaction temperature, co-catalysts, and metal hydroxides. The amount of formaldehyde relative to [Ca] is the most important factor in obtaining the selective formation of the three-branched sugar alcohols. Under these reaction conditions, the α,β-enediol structure is required in an effective co-catalyst for the formose reaction. 2-(Hydroxymethyl)glycerol, 3-(hydroxymethyl)pentitol, and 2,4-bis(hydroxymethyl)pentitol were formed with a high selectivity in the formose reactions catalyzed by KOH, Mg(OH)2, Fe(OH)3, and LiOH.
Kinetic Study on the Reaction of (Arylthio)trimethylsilanes with Phenacyl Bromide Giving Aryl Phenacyl Sulfides and Bromotrimethylsilane
Authors: Kozuka Seizi , Higashino Tetsuji , Kitamura Takuro 
Published: July 2006

Abstract
A kinetic study has been conducted on the reactions of (arylthio)trimethylsilanes with phenacyl bromide giving aryl phenacyl sulfides and bromotrimethylsilane. Remarkably large positive substituent effect (ρ=+2.2) and large negative entropy of activation were observed for the reaction. A mechanism involving 5-coordinated silicon intermediate prior to the rate-determining heterolysis of the Si–S bond has been suggested for the reaction based on the kinetic results.
Polarographic Studies on Oxygen Transport by Human Hemoglobin in Buffer Solutions
Authors: Hayashi Katsumi , Takagi Masanosuke 
Published: July 2006

Abstract
Oxygen transport by human hemoglobin (Hb) to an electrode surface with hypo-oxygen partial pressure has been studied by the polarographic technique. The oxygen reduction current in Hb solution open to the atmosphere increased linearly with Hb concentration up to ca. 2 mM (1 M=1 mol dm−3) heme. The current was ascribed to free and Hb bound oxygen. The increase in current with Hb concentration was attributed to the increasing oxygen supply to the electrode from oxygen bound Hb (oxyhemoglobin;oxyHb). Changes in temperature and pH largely affected the current, corresponding to the change in dissociation rate of oxygen from oxyHb. The relation between the current due to oxyHb and the apparent first order rate constant of the dissociation (k) measured by the stopped-flow method implies two different rate-determining steps of oxygen transport by Hb. When k exceeded ca. 60 s−1, the limiting step altered from the dissociation of oxygen to the diffusion of Hb molecules. It is concluded that the oxygen transport by Hb on physiological conditions is controlled by the diffusion of Hb. The diffusion coefficient of Hb in 20 mM heme as found in erythrocytes was estimated to be 5.8×10−8cm2 s−1 at 25 °C and pH 7.4.
Synthesis of (+)-11-Hydroxyabieta-2,8,11,13-tetraen-1-one
Authors: Matsumoto Takashi , Imai Sachihiko , Yuki Shuhei 
Published: July 2006

Abstract
Treatment of methyl (+)-11-oxo-13β-abieta-8-en-18-oate with copper(II) bromide and lithium bromide afforded the corresponding phenol derivative, which was methylated to methyl 11-methoxyabieta-8,11,13-trien-18-oate (7). The same compound was also prepared from methyl (+)-7,11-dioxo-13β-abieta-8-en-18-oate via methyl 11-hydroxy-7-oxoabieta-8,11,13-trien-18-oate, its methyl ether, and methyl 11-methoxyabieta-6,8,11,13-tetraen-18-oate. The Grignard reaction of 7 with phenylmagnesium bromide followed by treatment with lead tetraacetate and subsequent oxidation with selenium dioxide afforded 11-methoxy-19-norabieta-4(18),8,11,13-tetraen-3α-ol (12), which was converted to 11-methoxy-19-norabieta-8,11,13-trien-3-one (20) by catalytic hydrogenation, Jones oxidation, and isomerization. The compound 20 was also obtained by Birch reduction of 11-methoxy-19-norabieta-4,8,11,13-tetraen-3-one prepared from 12 via 11-methoxy-19-norabieta-4,8,11,13-tetraen-3α-ol. Subsequently, the compound 20 was transformed to 11-methoxyabieta-1,8,11,13-tetraen-3-one (27) by a series of reactions: acetalization, demethylation, hydrolysis, acetylation, bromination, dehydrobromination, and methylation. Finally, the compound 27 was converted to the title compound, (+)-11-hydroxyabieta-2,8,11,13-tetraen-1-one (1), by oxidation with alkaline hydrogen peroxide, heating with hydrazine hydrate, Jones oxidation, and demethylation. Although the synthetic (+)-1 was shown to be different from natural shonanol, the spectral analyses of the synthetic structural isomers showed the structure of shonanol to be 12-hydroxyabieta-2,8,11,13-tetraen-1-one.
The Coordination of the Perchlorate Ion. I. The Crystal and Molecular Structure of Bis(perchlorato)bis(pyrazine-2,3-dicarboxamide)copper(II)
Authors: Sekizaki Masao 
Published: July 2006

Abstract
Bis(perchlorato)bis(pyrazine-2,3-dicarboxamide)copper(II) has been prepared, and its crystal and molecular structure has been determined by the X-ray diffraction and the infrared spectroscopic methods. The crystals are triclinic with a space group P\bar1; a=10.959(4), b=6.970(3), c=7.666(3) Å, α=116.63(3), β=78.14(5), and γ=97.27(5)°, and Z=1. The refinement of the crystal structure has been carried out by a block-diagonal least-squares method to give R=0.054 for 1727 non-zero reflections. The complex is centrosymmetric, with the two bidentate ligand molecules chelating to the copper atom in trans positions through the amide oxygen and pyrazine nitrogen atoms to form a square-plane. The two perchlorate ions coordinate weakly to the copper atom through the oxygen atoms from the top and bottom of this plane; thus, an elongated octahedron is formed. The complex molecules are connected to one another by N–O type hydrogen bonds to form a three-dimensional network. The infrared spectrum has been compared with that of the chloride complex. The KBr region clearly show the symmetry depression of the perchlorate ion from Td to C3v on coordination.
Catalysis by Alkaline Earth Metal Oxides. III. X-Ray Photoelectron Spectroscopic Study of Catalytically Active MgO, CaO, and BaO Surfaces
Authors: Inoue Yasunobu , Yasumori Iwao 
Published: July 2006

Abstract
X-Ray photoelectron spectroscopy was used to reveal the surface states of MgO, CaO, and BaO oxides, which are catalytically active for ethylene hydrogenation. The catalytic activity of CaO exposed to H2O changed with an increase in the temperature of evacuation in a way similar to that of Ca(OH)2 decomposed by heat treatment. The photoelectron spectrum of CaO evacuated at 1223 K showed a peak of O Is at 529.6 eV, while those of Ca 2p3⁄2 were at 346.3 eV and Ca 2p1⁄2 at 349.8 eV. The adsorption of H2O at room temperature gave rise to an additional peak of O Is at 532.4 eV and one of Ca 2p3⁄2 at 348.6 eV, which were attributed to a Ca–O–H structure. With an increase in the temperature of evacuation from 553 to 1053 K, at which the catalytic activity attained a maximum, the latter O Is peak shifted to the lower binding-energy side by 0.4 eV, and the corresponding Ca 2p peak became broader. These spectral variations were ascribable to the formation of O− species. Evacuation above 1273 K destroyed both the catalytic activity and characteristic peaks. BaO provided three O Is peaks, at 528.5, 530.6, and 532.1 eV, after evacuation at 1373 K; these peaks were assigned to lattice oxygen of the oxide, O−, and OH− species respectively. The Ba 4d spectra showed correspondingly superposed peaks. The XPS peak due to O− was observed only when BaO was evacuated at temperatures high enough to generate the catalytic activity. Such spectral features were less pronounced in the case of MgO. The structural analysis of CaO showed that the coordinatively unsaturated cations also play a role in the catalytic hydrogenation. On the basis of these findings, it was concluded that a combined structure of O− and the cations is responsible for the hydrogenation activity.
Photolysis of Sodium Arenesulfonates in Alkaline Dimethyl Sulfoxide Solutions
Authors: Suzuki Nobutaka , Ito Kinya , Izawa Yasuji 
Published: July 2006

Abstract
Photolysis of arenesulfonates in alkaline DMSO under air gave the corresponding desulfonation products, arenes, presumably via the π-π* excited triplet state.
N-Trifluoroacetylimidazoles as a Reagent for Converting Aldoximes into Nitriles under Mild Conditions
Authors: Keumi Takashi , Yamamoto Takayoshi , Saga Hiroshi , Kitajima Hidehiko 
Published: July 2006

Abstract
It was found that N-trifluoroacetylimidazole was an excellent reagent for the intramolecular dehydration of aldoximes to give nitriles uner mold conditions.
Preparation and Oxidation of Europium(II) Niobium Bronze EuxNbO3−y
Authors: Ishikawa Kenji , Adachi Gin-ya , Tanida Midori , Shiokawa Jiro 
Published: July 2006

Abstract
Mixed oxides containing bivalent europium, EuxNbO3−y (0.5&lt;x&lt;1.0), were synthesized by the solid state reaction of Eu2O3, Nb2O5, and Nb powder. The structural change of EuxNbO3−y from a tetragonal to cubic form takes place at x=0.65. The mechanism of oxidation for the bronzes was studied. Each bronze shows different behavior in oxidation, the cubic bronze giving an amorphous phase and the tetragonal bronze complex crystalline products. EuNbO4 was crystallized from both the amorphous and crystalline phases at 950 K and 1070 K, respectively. TG-DTA and magnetic studies indicated that the oxidized phases play an important role in the rate-determining step of oxidation for the bronzes.
High Resolution Proton Nuclear Magnetic Resonance Studies of Solute Molecules in the Poly(vinylalcohol) Gel Medium
Authors: Fujiwara Shizuo , Fujikura Ryo , Ogino Takashi , Tanaka Michiko , Arata Yoji 
Published: July 2006

Abstract
It was shown that a pair of spectra is observed for each solute in the medium of poly(vinylalcohol) gels swollen in water. Each of the spectra was assigned as originating from the solute in the PVA gel itself and that in the bulk solution surrounding the gel. It was concluded that the chemical shift difference is primarily explained in terms of the difference in the volume susceptibility of the PVA gel and the bulk solution. It was observed in the case of nicotinamide adenine dinucleotide (NAD) that the chemical shift differences are different for different functional groups. We suggest that this observation reflects a contribution from intermolecular interaction between PVA gel and the NAD molecule.
Dynamic Properties of the Phosphorescent Triplet State of 9H-Thioxanthen-9-one (Thioxanthone) from Optically Detected Magnetic Resonance Spectroscopy
Authors: Suga Kazuhiko , Kinoshita Minoru 
Published: July 2006

Abstract
A variety of optically detected magnetic resonance (ODMR) experiments have been performed on the lowest excited triplet state of 9H-thioxanthen-9-one at 1.4 K. The absorption and phosphorescence excitation spectra were also measured to supplement the ODMR studies. The results were analyzed to determine the mechanisms responsible for the radiative decay and intersystem crossing processes. The z sublevel has large activity in vibronic bands due to non-totally symmetric vibrations. The intensity mainly comes from mechanisms involving vibronic coupling between 1n,π* and 1π,π* states. The y sublevel is selectively affected by the introduction of the sulfur atom, because of the increased importance of spin orbit coupling with 1σ′,π* state which is largely localized on the thioether group.
Kinetic Studies of the Oxidation Reactions of o-, m-, and p-Benzenediols with Tris(1,10-phenanthroline)iron(III). An Estimation of the Redox Potentials of the Organic Radicals by Application of the Marcus Theory
Authors: Kimura Masaru , Yamabe Shinichi , Minato Tsutomu 
Published: July 2006

Abstract
Kinetic studies of the oxidation of o-, m-, and p-benzenediols (H2A) by tris(1,10-phenanthroline)iron(III) were made in dilute perchloric acid solution at an ionic strength of 1.0 mol dm−3 at four temperatures between 10 and 30 °C. The second-order rate constants (k0) which follow the observed rate law of –d [Fe(phen)33+]/dt=k0[Fe(phen)33+][H2A] were determined under varied conditions. The order of the rate constants was m-&lt;o-&lt;p-benzenediols, with the ratio being approximately 1 : 103 : 104. By the application of the Marcus theory to the kinetic parameters obtained, the standard redox potentials of the dihydroxyphenyl radicals (H2A\underset.+) were estimated in 0.11 mol dm−3 perchloric acid solution to be 1.41, 1.10, and 0.97 V for m-, o-, and p-benzenediols, respectively. The energies of the highest occupied molecular orbitals for the H2A molecules (εHOMO) were calculated to be −0.4468, −0.4332, and −0.4224 a.u. for m-, o-, and p-benzenediols, respectively. The differences of the total electronic energies between H2A\underset.+ and H2A molecules (ΔET) were calculated to be 0.4183, 0.4033, and 0.3957 a.u. for m-, o-, and p-benzenediols, respectively. Thus, the standard redox potentials of the free-radicals estimated are found to be well correlated with the HOMO energies and also with the differences of the total electronic energies between the cation radicals and the parent molecules.
Kinetics and Equilibrium of the Reaction between Bis(trifluoroacetylacetonato)palladium(II) and Tri-o-tolylphosphine
Authors: Matsumoto Shinichi , Kawaguchi Shinichi 
Published: July 2006

Abstract
Tri-o-tolylphosphine reacts with bis(trifluoroacetylacetonato)palladium(II), Pd(tfac)2, to convert one of the chelating ligands into the unidentate state, resulting in Pd(tfac)(tfac-O)P(o-tolyl)3. The reaction was studied by a spectrophotometric method. The equilibrium constant was determined at several temperatures, K being 1.38×103, 4.35×103 dm3 mol−1 and more than 109 dm3 mol−1 in benzene, dichloromethane, and methanol, respectively, at 25 °C. In the presence of excess phosphine, the reaction proceeds as a pseudo first order reaction to attain equilibrium. The forward and reverse rate constants, k1 and k−1, were obtained as 0.172 dm3 mol−1 s−1 and 1.22×10−4 s−1 in benzene and 2.28 dm3 mol−1 s−1 and 4.9×10−4 s−1 in dichloromethane at 25 °C, respectively. In methanol the forward rate was measured under irreversible pseudo first order conditions and conforms with the usual two term rate law, kobsd⁄s−1=2×10−3+56.6[P(o-tolyl)3]. The remarkable dependence of K and k1 on the nature of solvent is related to the hydrogen bonding interaction between the carbonyl group of the coordinated tfac anion and a solvent molecule.
Studies on Window Sweep Chronopotentiometry. I. Fundamental Concept, Methodology, and Analytical Application
Authors: Kato Yoshikiyo , Yamada Akifumi , Yoshida Norimasa , Unoura Kei , Tanaka Nobuyuki 
Published: July 2006

Abstract
Window sweep chronopotentiometry, a new galvanostatic method, has been worked out, the electronic circuit of a window sweep chronopotentiograph and digital simulation of the window sweep chronopotentiogram being presented. Analytical application demonstrating the increase in sensitivity of the galvanostatic method for quantitative analysis is presented.
Nucleophilic Reactions of Hydrazido(2–) Complexes of Molybdenum and Tungsten with Succinyl Dichloride and Phenyl Isocyanate
Authors: Iwanami Kiyotaka , Mizobe Yasushi , Takahashi Tamotsu , Kodama Teruyuki , Uchida Yasuzo , Hidai Masanobu 
Published: July 2006

Abstract
Nucleophilic attack of the WNNH2 group in the hydrazido(2-) complex [WF(NNH2)(dpe)2][BF4] (dpe=Ph2PCH2CH2PPh2) on succinyl dichloride gives a novel ethanedioylhydrazido(2-) complex, [WF(NNCOCH2CH2CO)(dpe)2][BF4]. X-Ray structural analysis shows that the carbon, nitrogen, and oxygen atoms of the ethanedioylhydrazido(2-) ligand lie nearly in the same plane, indicating sp2 character of the nitrogen atom bearing the two carbonyl groups. Phenyl isocyanate also undergoes nucleophilic attack by the hydrazido(2-) complex [MBr(NNH2)(dpe)2]Br (M=Mo or W) to yield the phenylsemicarbazido(2-) type complex, [MBr(NNHCONHPh)(dpe)2Br. Treatment of the semicarbazido(2-) complex with triethylamine gives a new diazenido complex [MBr(NNCONHPh)(dpe)2].
The Thermal Decomposition of N,O-Diacyl-N-t-butylhydroxylamines. II. Thermal Rearrangement of O-Acyl-N-[2-(methylthio)-benzoyl]-N-t-butylhydroxylamines
Authors: Uchida Yuzuru , Kobayashi Yusho , Kozuka Seizi 
Published: July 2006

Abstract
Several O-acyl-N-[2-(methylthio)benzoyl]-N-t-butylhydroxylamines (1) were prepared and their thermal decompositions were studied. The thermal decomposition of 1 at 200 °C in o-dichlorobenzene gave N-t-butyl-2-(acyloxymethylthio)benzamide (4), the carboxylic acid derived from the acyl part of 1, and 2-t-butyl-1,2-benzothiazol-3(2H)-one as the main products, together with small amounts of 4H-3,1-benzoxathiin-4-one, N-t-butyl-2-(methylthio)benzamide, methyl ester of the carboxylic acid, and N-t-butylamide. The benzamide (4) was found to be an initial product of the thermolysis and the subsequent decomposition gave the carboxylic acid and other products. Pummerer type reaction, via acylaminosulfonium ion as the intermediate, was suggested for the thermal decomposition of 1 since similar products were also obtained by the Pummerer reaction of N-t-butyl-2-(methylsulfinyl)benzamide with acylating reagents.
Thermal Reactions of Metal Complexes under Quasi-isothermal and -isobaric Conditions. II Formation of Triamminetrihalogenochromium(III) Complexes via the Decomposition of Hexaammine, Pentaamminehalogeno, and trans-Tetraamminedihalogeno Complexes
Authors: Ueno Hitoshi , Uehara Akira , Tsuchiya Ryokichi 
Published: July 2006

Abstract
The thermal decomposition of the following chromium(III) complexes was investigated in the solid phase by means of Q-derivatograph under quasi-isothermal and -isobaric conditions (Q-conditions) and D-derivatograph under dynamic conditions (D-conditions): [Cr(NH3)6]X3, [CrX(NH3)5]Y2, and trans-[CrX2(NH3)4]Y, where X and Y are chloride and/or bromide ions. The complexes were finally converted into triamminetrihalogeno complexes [CrBrxCly(NH3)3] (x+y=3; x and y=0, 1, 2, or 3) under Q-conditions but decomposed in complicated ways under D-conditions. All the triamminetrihalogeno complexes thus obtained have mer-configuration with respect to the positions of the three halide ions.
Binuclear Metal Complexes, XXXIX. Synthesis and Properties of Binuclear Copper(II) Complexes with [2-(2-Pyridyl)ethylamino]alkanols and [2-(2-Pyridyl)ethylthio]alkanols
Authors: Nakamura Masaaki , Mikuriya Masahiro , Okawa Hisashi , Kida Sigeo 
Published: July 2006

Abstract
Di-μ-alkoxo-bridged binuclear copper(II) complexes, Cu(py-3-3-nno)X, Cu(py-3-2-nso)X, and Cu(py-3-3-nso)X (X=Cl, Br, ClO4, NO3, PF6, BF4), have been synthesized and characterized, where Hpy-3-3-nno, Hpy-3-2-nso, and Hpy-3-3-nso denote 3-[2-(2-pyridyl)ethylamino]-1-propanol, 2-[2-(2-pyridyl)ethylthio]ethanol, and 3-[2-(2-pyridyl)ethylthio]-1-propanol, respectively. It was found that 2-[2-(2-pyridyl)ethylamino]ethanol (Hpy-3-2-nno) cannot form di-μ-alkoxo-bridged binuclear copper(II) complexes owing to the high strain in the fused ring system. These complexes exhibited a band at 22000–27000 cm−1 characteristic of the di-μ-alkoxo-bridged structure, the bands for Cu(py-3-2-nso)X and Cu(py-3-3-nso)X being lower in frequency compared with those for Cu(py-3-3-nno)X. Antiferromagnetic interaction was stronger and reduction potential (Cu(II)–Cu(II)→Cu(I)–Cu(I)) was higher for Cu(py-3-3-nso)X than those for Cu(py-3-3-nno)X. Cu(py-3-3-nso)Cl and Cu-(py-3-2-nso)Br showed two reduction waves at about +0.15 and −0.4 V vs. SCE. These results were discussed in terms of the structure in solution on the basis of conductivity measurements.
Synthesis of New Chiral Phase-transfer Catalysts and Their Application to Michael Additions
Authors: Banfi Stefano , Cinquini Mauro , Colonna Stefano 
Published: July 2006

Abstract
A series of chiral onium salts derived from (l)-(+)-methionine have been examined for the catalysis of Michael additions in phase-transfer conditions. The chemical yields are high, but no asymmetric induction was observed. Catalyst 6 represents the first example of an onium salt anchored to a polimeric matrix having a higher catalytic efficiency than its soluble counterpart.