bluuebunny/crossref_metadata_2025_split huggingface dataset:
ESR Studies of Temperature Dependent Zero-field Splitting in Yang’s Biradical
Authors: Mukai Kazuo , Ishizu Kazuhiko , Nakahara Mizue , Deguchi Yasuo 
Published: July 2006

Abstract
The ESR absorptions of Yang’s biradical in a few organic solvents have been studied in detail as a function of temperature, and the effect of temperature on the symmetry of the biradical molecule has been discussed on the basis of the temperature dependence of the zerofield splitting parameters.
Catalysis by Heteropolyacid. III. Acylation and Sulfonylation of Aromatic Compounds Catalyzed by Keggin-structure Heteropolyacids
Authors: Nomiya Kenji , Sugaya Yoshio , Miwa Makoto 
Published: July 2006

Abstract
Catalytic acylation and sulfonylation reactions of aromatic compounds by Keggin-structure heteropolyacids, H4[SiMo12O40], H3[PMo12O40] and H4[SiW12O40], have been studied. Tungsten is more effective than molybdenum for the reactions.
The Fraction of Bound Segments and the Chain Motion of Adsorbed Poly(methyl methacrylate) at the Solution-Solid Interface as Studied by Electron Spin Resonance
Authors: Sakai Harutoshi , Fujimori Toshihiko , Imamura Yoshio 
Published: July 2006

Abstract
The configuration of poly(methyl methacrylate) adsorbed on silica from dilute solution (CCl4, benzene, and CHCl3) was studied from the point of view of the chain motion by a spin-labeling technique. The ESR spectrum of the adsorbed polymer was found to be composed of three portions, which had considerably different degrees of the motional freedom of the local chain segments. The rotational correlation times corresponding to the three portions were estimated by the line shape analysis and the rapid passage technique. These times were 1×10−9, 5×10−9, and longer than 10−6 s, and were attributed to the motions in the long loop, short loop, and train, respectively. The large fractions of the bound segments, obtained in all the cases of low surface coverage, showed highly flattened structures of the adsorbed chain molecules. In the adsorption from a poor solvent (CCl4), a strongly compressed structure with a large number of the short loops was found. The adsorbed layer thickness, indicated by the fraction of the segments in the three states, became much smaller with an increase in the solvent power and a decrease in the surface coverage.
Laser Induced Biphotonic Dissociation of Nitrobenzene Derivatives in Solution
Authors: Yokoyama Kenji , Nakamura Junko , Kobayashi Takayoshi , Nagakura Saburo 
Published: July 2006

Abstract
By irradiation with a focused laser beam, p-nitroanisole and N-[2-(p-nitrophenoxy)ethyl] aniline (2) in acetonitrile were found to show new reactions yielding nitroso compounds different from the case of the defocused laser beam irradiation. The laser intensity dependence of the product yield shows that the new reaction of 2 proceeds via a biphotonic process. The quenching effects of oxygen and cis-1,3-pentadiene upon the reaction rate indicate that the intermediate state is an excited singlet state.
A Kinetic Study on the Proton-transfer Reactions of Bis(dimethyl-glyoximato)cobalt (III) Complex Ions in Dioxane–Water Media
Authors: Yoshida Noboru , Fujimoto Masatoshi 
Published: July 2006

Abstract
The proton-transfer reactions of bis(dimethylglyoximato)cobalt(III) complex ions, [CoIII(dmgH)2X2]n, with hydroxide ion, OH−, were studied in dioxane–water media by means of a temperature-jump method. The rate constant, kf, for the direct proton-transfer from [CoIII(dmgH)2X2]n to OH− was found to be 1.6×105–2.9×106 mol−1 dm3 s−1 in aqueous solution. The value of kf for [CoIII(dmgH)2(CN)2]− anion decreased gradually from 1.6×105 to 4.0×104 mol−1 dm3 s−1 for the change in the mole fraction of dioxane, xdiox, from 0 to 0.174. On the other hand, with increase in xdiox, the value of kf for [CoIII(dmgH)2(NH3)2]+ cation gradually decreased from 2.9×106 to 1.1×107 mol−1 dm3 s−1 in a region of lower xdiox, and then increased from 1.1×106 to 1.6×106 mol−1 dm3 s−1 in a region of higher xdiox. The dependence of kf on xdiox is interpreted in connection with reaction mechanism.
The Thermal Decomposition of Ammonium Chloride Tetrachlorozincate and the Formation of Tetrachlorozincate Complexes of Alkali Metal by Means of Solid Reactions with Alkali Chlorides
Authors: Ichiba Sumio , Oshima Satoshi , Negita Hisao , Tanaka Haruhiko 
Published: July 2006

Abstract
Ammonium chloride tetrachlorozincate, (NH4)3Cl[ZnCl4], decomposes to ZnCl2 in two stages through an intermediate phase (NH4)2[ZnCl4]. In the first stage, 1 mol of NH4Cl is lost by one-dimensional diffusion mechanisms with the activation energy of 138 kJ mol−1, and in the second stage the release of two moles of NH4Cl is controlled by a random nucleation reaction with the activation energy of 126 kJ mol−1, corresponding to the bondbreaking. Anhydrous alkali metal tetrachlorozincate complexes, M2[ZnCl4](M=Na, K, Rb, Cs), are obtained by solid reactions with alkali chlorides when (NH4)3Cl[ZnCl4] decomposes. A dry chemical method using (NH4)3Cl[ZnCl4] as a starting material is proposed for the preparation of the anhydrous chlorozincate complexes, which have thus far been difficult to synthesize.
Kinetic Studies of Fast Equilibrium by High-performance Liquid Chromatography I. Ternary Complex Formation of N,N-Disubstituted Dithiocarbamate Chelates of Ni(II) and Cu(II)
Authors: Moriyasu Masataka , Hashimoto Yohei 
Published: July 2006

Abstract
The equilibrium of labile ternary complex formation of metal dialkyldithiocarbamate chelates (MA2+MB2\oversetk\undersetk−\ightleftharpoons 2MAB, K=[MAB]2/[MA2][MB2]) has been investigated by high-performance liquid chromatography, the separation process of which is so fast that kinetically unstable ternary complexes can be eluted with no disproportionation during the course of chromatography. High-performance liquid chromatography makes it possible to halt the progress of considerably fast reactions at the moment when the solution of reaction system is injected into the column. Thus, chromatograms obtained indicate the concentration of each species before chromatography, facilitating the determination of equilibrium constant K of Ni(II) and Cu(II) chelates. The equilibrium constants obtained are always 4.0, suggesting that ternary complex formation is controlled by a statistical factor. Disproportionation takes place by collision of two ternary metal chelates, the rate constants being of the order 101–102 M−1 s−1 (Ni(II) chelates) and 103 M−1 s−1 (Cu(II) chelates). The activation parameters of ternary complex formation have been obtained.
Synthetic Photochemistry. XIX. The Synthesis of Protoilludanes by Photocycloadditions, Protoillud-7-ene and Several Oxygenated Derivatives
Authors: Takeshita Hitoshi , Kouno Isao , Iino Mitsuaki , Iwabuchi Hisakatsu , Nomura Danji 
Published: July 2006

Abstract
Unlike ethylene, 1,1-dimethoxyethene, an electron-rich olefin, has been photocycloadded to a cis-hexahydroindenone to form a norprotoilludane derivative with a correct stereostructure. Methylation and subsequent chemical transformations yielded several oxygenated derivatives, from which the parent hydrocarbon, protoillud-7-ene, was obtained by deoxygenation. Independent evidence for the stereostructures of the synthetic derivatives has been provided by the X-ray crystallographic analysis of a dihydroxy acetal.
The Stereochemical Course of the Photochemical Berson-Willcott Rearrangement of exo-1-Methoxycarbonylmethyl-3-t-butyl-1a,7b-dihydro-1H-cyclopropa[a]naphthalene to 7-Methoxy-carbonylmethyl-5-t-butyl-7H-benzocycloheptene
Authors: Kato Masahiko , Takatoku Keizo , Ito Satoru , Funakura Mitsuru , Miwa Toshio 
Published: July 2006

Abstract
The photolysis of (1S)-exo-1-methoxycarbonylmethyl-3-t-butyl-1a,7b-dihydro-1H-cyclopropa[a]naphthalene gave (7S)-5-t-butyl-7-methoxycarbonylmethyl-7H-benzocycloheptene by a 1,5-sigmatropic shift, proving the rearrangement to proceed with the inversion of the configuration of the migrating center.
New Monoterpene Lactones of the Iridane Type from Actinidia polygama Miq.
Authors: Sakai Tsutomu , Nakajima Kimiko , Sakan Takeo 
Published: July 2006

Abstract
Fourteen iridoid monoterpene lactones including eight new compounds were isolated from the volatile oil of fresh fruits of the cat- and lacewing-attracting plant Actinidia polygama Miq., and their structures were established on the basis of spectral evidence and chemical transformation.
Synthesis and Stereochemistry of 2,3,4,6-Tetra-O-benzyl-d-gluco-pyranosylidene Acetals of α-Diols and Monosaccharides
Authors: Tamaru Masatoshi , Horito Shigeomi , Yoshimura Juji 
Published: July 2006

Abstract
The title compounds were synthesized by addition of 2,3,4,6-tetra-O-benzyl-d-glucono-1,5-lactone to epoxides and by direct dehydration between the lactone and diols in the presence of concentrated sulfuric acid as a catalyst. Stereochemistry of these spiro cyclic acetals was discussed.
Classification of the External Magnetic Field Effects on the Photodecomposition Reaction of Dibenzoyl Peroxide
Authors: Sakaguchi Yoshio , Hayashi Hisaharu , Nagakura Saburo 
Published: July 2006

Abstract
The external magnetic field effects upon product yields in the singlet sensitized photolysis of dibenzoyl peroxide in toluene were studied. The observed field dependencies were classified into four types, and were interpreted in terms of the electronic Zeeman and hyperfine interactions in the intermediate radical pair. Especially large magnetic field effects were observed for the yields of dimethylbiphenyls, new products in this reaction.
Intramolecular Cycloaddition Reactions of N-Sulfonyl Nitrile Imides Bearing Alkenyl Groups
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Nagano Yoshio , Teramura Kazuhiro 
Published: July 2006

Abstract
The reaction of the p-tolyl(or phenyl)sulfonylhydrazones of some 2-(alkenyloxy)benzaldehydes with lead tetraacetate leads, via the nitrile imide intermediates, Ar–\overset+C=N–\overset−N–SO2–C6H4–X-p, to intramolecular 1,3-dipolar cycloadducts and 1-acetyl-2-aroyl-1-[p-tolyl(or phenyl)sulfonyl]hydrazines in 20–65% and 7–70% yields respectively, while the intermolecular reactions of the benzaldehyde p-tolylsulfonylhydrazone with a dipolarophile such as acrylonitrile or styrene in the presence of lead tetraacetate gives only 1-acetyl-2-benzoyl-1-(p-tolylsulfonyl)hydrazine. The treatment of the N-(p-tolylsulfonyl)-o-(allyloxy)benzohydrazonoyl chloride (10) with triethylamine or by refluxing a benzene solution of 10 also gives an intramolecular 1,3-dipolar cycloadduct in a good yield.
Light Scattering Study of Local Structure in Solutions. Importance of Temperature Dependency Measurements
Authors: Kato Tadashi , Yano Katsuaki , Fujiyama Tsunetake 
Published: July 2006

Abstract
Light scattering spectra have been observed for binary solutions of acetic acid and carbon tetrachloride at several concentrations and temperatures. The Rayleigh intensities were reduced to concentration fluctuations. The observed concentration and temperature dependencies of concentration fluctuation were interpreted by assuming association equilibria involving both cyclic dimers and linear polymers. The simultaneous measurement of concentration and temperature dependencies of concentration fluctuation are necessary to determine local structures in solutions where different types of local structure coexist.
Ab Initio Studies of the Hydrogen Atom Addition to Ethylene
Authors: Nomura Okio , Iwata Suehiro 
Published: July 2006

Abstract
The ethyl radical formation from hydrogen and ethylene was studied with ab initio open shell SCF and CI methods. At first, the minimal basis set (STO-6G) was used to determine a minimal energy path. The calculated exothermicity and the height of the barrier were 72.3 kcal/mol and 16.9 kcal/mol, respectively. After the full geometry optimization with the double zeta basis set the calculated exothermicity became 38.3 kcal/mol, which is in agreement with the experimental value (40.1 kcal/mol), but the barrier height (16.5 kcal/mol) was no better than that obtained by the minimal basis set. After the extensive CI calculations along Sloane and Hase’s path with the minimal basis set, the calculated height of the barrier became only 5.1 kcal/mol. The small but finite barrier height is important in this reaction. The successive hydrogenation to form ethane was also studied and no barrier was found in the reaction.
Absorption Spectra of the Polyacetylene Films Doped with BF3
Authors: Tanaka Masashi , Watanabe Atsushi , Tanaka Jiro 
Published: July 2006

Abstract
Optical absorption measurements are carried out on pure and BF3 doped polyacetylene films over a wide wavelength region (200 cm−1–54000 cm−1). In the lightly doped polymer, the extra peak appears at 870 cm−1 and it is assigned to the transition from the valence band to the impurity level. This band becomes more intense at low temperature. For the heavily doped films, the dc conductivity of the (CH)x fibril is optically estimated to be σ0=104 Ω−1 cm−1. This value is in good agreement with the calculated value (σ0=0.8×104 Ω−1 cm−1) due to the tight binding model.
Equilibrium Study of Iron Vanadium Sulfides in the Iron-rich Portion of the Composition Triangle of FeS–VS–S
Authors: Wada Hiroaki 
Published: July 2006

Abstract
An equilibrium study of a part of the Fe–V–S system at sections with atomic Fe: V ratios of 1:0, 9:1, and 4:1 was carried out by means of thermogravimetry. The thermochemical data which were obtained in the range of log(PS2/atm)=−4 to −0.8 at temperatures between 520 and 814 °C are presented. The compositional limits of the univariant assemblage of Fe1−δS–FeS2–(Fe,V)3S4 were determined at 570 °C on the basis of X-ray analyses of the quenched specimens. The rate of FeS2 formation under the experimental conditions employed was studied qualitatively from the point of view of the sulfidation kinetics of iron vanadium sulfides.
Transition Metal Alkoxides. Preparation and Properties of Bis(aryloxo)iron(II) and Bis(alkoxo)iron(II) Complexes Having 2,2′-Bipyridine Ligands
Authors: Komiya Sanshiro , Tane-ichi Shoshiro , Yamamoto Akio , Yamamoto Takakazu 
Published: July 2006

Abstract
A series of bis(aryloxo)iron(II), 2a–2g, and bis(alkoxo)iron(II), 2h–2k, complexes with 2,2′-bipyridine ligands (Fe(OC6H4X)2(bpy)n and Fe(OR)2(bpy)n) have been prepared by the reactions of diethylbis(2,2′-bipyridine)iron(II) (1) with corresponding p-substituted phenols and alcohols, respectively. (X=NO2, CN, Cl, C6H5, H, and CH3; R=CH3, C2H5, iso-C3H7, and CH2C6H5). These compounds were characterized by IR and NMR spectroscopies and elemental analyses as well as by chemical reactions. Kinetic investigation of the reactions of 1 with phenols by a visible spectroscopic method supports a mechanism involving partial dissociation of the 2,2′-bipyridine ligand, followed by coordination of phenol and activation of the Fe–C2H5 bonds giving the bis(phenoxo)iron(II) compound. Thermolysis of bis(alkoxo)iron(II) complexes gives not only disproportionation products of the alkoxo ligands (alcohols and aldehydes) but also organic products which are obtained as the result of C–O bond cleavage of the alkoxo groups. Interactions of 2 with acyl and alkyl halides lead to the formation of corresponding esters and ethers. Reactions of these iron(II) complexes with various organic acetates give corresponding acetates via an alkoxo exchange reaction. Bis(aryloxo)iron(II) complexes, 2, are hydrolyzed with H2O to yield phenols. Catalytic trans-esteriflcation between ester and alcohol and Tishchenko type dimerization of benzaldehyde are effectively promoted under mild conditions by the bis(phenoxo)iron(II) and bis(benzyloxo)iron(II) complexes, respectively.
Physical Properties and Various Reactions of Thionitrites and Related Substances
Authors: Oae Shigeru , Shinhama K\={o}ichi , Fujimori Ken , Kim Yong Hae 
Published: July 2006

Abstract
Several new sulfonyl or sulfonyl derivativives, thionitrates (RSNO2), sulfonyl nitrites (RSO2NO), were successfully isolated by treating corresponding thiols and sulfinic acids with dinitrogen tetraoxide (N2O4). Spectroscopic data of both stable and many rather unstable compounds were determined and compared with those of corresponding alkyl nitrites (RONO) or alkyl nitrates (RONO2). Chemical reactivities of these uncommon, novel S-nitroso and S-nitro compounds were investigated.
Chemiluminescence of a Cypridina Luciferin Analogue, 2-Methyl-6-phenyl-3,7-dihydroimidazo[1,2-a]pyrazin-3-one, in the Presence of the Xanthine–Xanthine Oxidase System
Authors: Goto Toshio , Takagi Tetsuyuki 
Published: July 2006

Abstract
The title compound chemiluminesces in aqueous solutions (pH 5–6.5) in the presence of xanthine–xanthine oxidase system; O2− and not 1O2 was proven to be the active species. Quantitative determination of xanthine and xanthine oxidase as low as 5 nmol and 10−5 unit, respectively, is possible by measurement of the chemiluminescence light yield and the reaction rate.
The Coprecipitation of Antimony(III or V) with Iron(III) Hydroxide
Authors: Inoue Yoshikazu , Munemori Makoto 
Published: July 2006

Abstract
The coprecipitation of antimony(III or V) with iron(III) hydroxide as a function of the pH in the range from 4 to 12 was studied in the presence of the chloride ion. Antimony(III) is coprecipitated more easily at any given pH value than antimony(V). The coprecipitation of antimony(III) is quantitative in the pH range from 4 to 10 and is not affected by the chloride ion. On the other hand, the coprecipitation of antimony(V) is affected not only by the pH range, but also by the chloride-ion concentration.
An X-Ray Diffraction Study on the Structures of Bis- and Tris(ethylenediamine)cadmium(II) Complexes in Solution
Authors: Fujita Tadao , Ohtaki Hitoshi 
Published: July 2006

Abstract
The structures of cadmium(II) complexes with ethylenediamine(en) have been determined by means of X-ray diffraction. The measurements were performed at 25 °C for aqueous ethylenediamine solutions of cadmium nitrate, the mole ratios (en/Cd) in the solutions being 2.188 and 3.387. In the solution of the lower en/Cd mole ratio, the bis(ethylenediamine)cadmium(II) complex was predominant, whereas in the other solution the tris(ethylenediamine)cadmium(II) complex was contained as the main species. From the analysis of the X-ray scattering data of the solutions, it was shown that in the bis-complex four nitrogen atoms within the two ethylenediamine molecules were tetrahedrally coordinated to the cadmium(II) ion at a distance of 2.339(4) Å. The nonbonding Cd···C distance within the bis-complex was also determined to be 3.04(1) Å. In the tris-complex the cadmium(II) ion was coordinated with six nitrogen atoms and the Cd–N and Cd···C distances were 2.371(5) and 3.19(1) Å, respectively. The strength of the Cd–N bond with changing coordination number of the complexes was discussed in terms of the frequencies of the Cd–N bond in the Raman spectra of these solutions and the bond lengths found from the X-ray scattering measurements.
An Application of the Extended Principal Component Analysis to Circular Dichroism and Optical Rotatory Dispersion. A Case of Poly(α-l-glutamic acid) in the Helix-Coil Transition Region
Authors: Yamaoka Kiwamu , Matsuda Takumi , Takatsuki Mineo 
Published: July 2006

Abstract
The extended principal-component-analysis (PCA) method has been applied to circular dichroism (CD) and optical rotatory dispersion (ORD). The validity of this method has been examined with ideal binary and ternary equilibrium systems, for which the data CD spectra and ORD curves were computer-generated. Satisfactory results were obtained for these multicomponent optically active systems. As an example, the ultraviolet CD spectra of poly(α-l-glutamic acid) in the pH-induced helix-coil transition region were analyzed with the PCA procedure. By the extended PCA method, the pure CD spectra for both helix and random-coil conformations and the helix fractions in the transition region were determined from eight experimentally obtained CD spectra. By introducing an empirical parameter α into the Henderson-Hasselbalch equation, the helix-coil transition curve was reproduced reasonably well.
The Removal and Solidification of Halogenide Ions Using a New Inorganic Compound
Authors: Kodama Hiroshi 
Published: July 2006

Abstract
The present paper discusses a new method for removing and solidifying halogenide ions from solution by a reaction with Bi5(NO3)O7. Since this compound is isostructural with Bi5(I)O7 or Bi5(Br)O7, an ion exchange of the halogen ions with NO3− is expected.
Bi5(NO3)O7 was reacted with aqueous halogenide ions at 25, 50, and 75 °C. The iodide ion was removed almost perfectly at 50 and 75 °C. The reactions were completed after 15 h. The bromide ion was also removed almost perfectly at 25, 50, and 75 °C. The reactions at 50 and 75 °C were completed after 24 h. The chloride ion was also removed by reactions at 50 and 75 °C, which were almost completed after about 48 h. The fluoride ion was not removed.
The iodide and bromide ions reacted with Bi5(NO3)O7 to form Bi5(X)O7 (X = I or Br), provided that their concentrations were below 2.0 and 1.0 mol dm−3, respectively. The chloride ion formed other types of compounds, such as Bi12(Cl2)O17 or Bi3(Cl)O4.
The ion-exchange capacities of iodide, bromide and chloride ions were observed at 50 and 75 °C.
Crystal Structures of trans- and cis-Anionobis(ethylenediamine)nitrosylruthenium(II) Complexes
Authors: Tomizawa Hiroshi , Miki Eiichi , Mizumachi Kunihiko , Ishimori Tatsujiro 
Published: July 2006

Abstract
The structures of trans-[RuX(en)2NO]X′2 (X = OH (1), Cl (3), or NCS (4), en = ethylenediamine, X′ = Br (1), Cl (3), or NCS (4)), trans-[Ru(H2O)(en)2NO]Cl3 (2), cis-[RuX(en)2NO]XPF6 (X = Cl (5), or Br (6)), and cis-[Ru(NCS)(en)2NO]I2·H2O (7) were determined by X-ray diffraction. In two pairs of the geometrical isomers (3 and 5, and 4 and 7), the Ru–Cl or the Ru–N(NCS) bond for the trans isomer was shorter than that for the cis isomer due to a trans-strengthening effect of the NO; this effect was not observed for the corresponding Ru–N(en) bond. These facts indicate that the effect is mainly caused by both σ- and π-bonding interactions of the ligand trans to NO through Ru, and is not caused by only the σ-donation of the ligand.
Studies on Mixed Chelates. XXII. Five-Coordinate Copper(II) Chelates with N,N,N′,N″,N″-Pentamethyldiethylenetriamine and β-Diketonates
Authors: Shintani Noriko , Nukui Etsuko , Miyamae Hiroshi , Fukuda Yutaka , Sone Kozo 
Published: July 2006

Abstract
Mixed Cu(II) chelates with N,N,N′,N″,N″-pentamethyldiethylenetriamine (pmdt) and five β-diketonate (dike) ligands, i.e., dipivaloylmethanate (dipm), acetylacetonate (acac), pivaloyltrifluoroacetonate (pfac), trifluoro- and hexafluoroacetylacetonate (tfac and hfac, respectively), were prepared and studied. Their general formula, [Cu(dike)(pmdt)]ClO4, suggests that they are five-coordinated; X-ray crystal analyses confirmed that the chelates with acac and tfac are distorted square pyramidal, with the axial site occupied by one of the O atoms of dike. Similar structures are presumed for the remaining chelates on the basis of spectral similarities. In solutions, these five-coordinated chelates are solvated to various extents, showing a characteristic solvatochromism.