bluuebunny/crossref_metadata_2025_split huggingface dataset:
Crystal and Molecular Structures of [Cu2(taec)X](ClO4)3·nH2O (taec=N,N′,N″,N'″-Tetrakis(2-aminoethyl)-1,4,8,11-tetraazacyclotetradecane; X=I, F, NO2, and CH3COO; n=0, 1, or 2). Effect of Incorporation of an Anion X on the Structure of the Complex Cation
Authors: Mikuriya Masahiro , Kida Sigeo , Murase Ichiro 
Published: July 2006

Abstract
The crystal structures of four binuclear copper(II) complexes of N,N′,N″,N'″-tetrakis(2-aminoethyl)-1,4,8,11-tetraazacyclotetradecane (taec), [Cu2(taec)I](ClO4)3(1), [Cu2(taec)F](ClO4)3·H2O (2), [Cu2(taec)(NO2)](ClO4)3(3), and [Cu2(taec)(CH3COO)](ClO4)3·2H2O (4), were determined by single-crystal X-ray analysis. In all the complexes, each copper is coordinated by two ring- and two pendant-nitrogen atoms. All the complexes except for 4 adopt similar structures, where I−, F−, or NO2− is incorporated into the “cavity” of [Cu2(taec)]4+ as a bridging group. The structure of 4 is different from those of 1, 2, and 3. In 4, one of the oxygen atoms of acetate ion coordinates to one of the copper ions at the apical site and the other oxygen occupies an in-plane coordination site of the other copper ion. The structural effect of incorporation of an anion, X, into [Cu2(taec)]4+ was discussed on the basis of the crystal structures.
CH3···O Hydrogen Bond. Implications of Its Presence from the Substituent Effects on the Populations of Rotamers in 4-Substituted 9-Ethyl-1-methoxytriptycenes and 9-(Substituted Phenoxymethyl)-1,4-dimethyltriptycenes
Authors: Tamura Yoshio , Yamamoto Gaku , Oki Michinori 
Published: July 2006

Abstract
In the series of 4-substituted 9-ethyl-1-methoxytriptycenes, the populations of the sc conformer increase as the electron-density on the 1-methoxy–oxygen decreases. This trend was interpreted on the basis of steric repulsion which should increase as the electron density on the oxygen atom becomes high. In contrast, in the series of 9-(substituted phenoxymethyl)-1,4-dimethyltriptycenes, the high electron density on the aryloxy–oxygen favors the sc form. The stabilization of the sc form relative to the ap in the high electron density compounds in the latter series is attributed to the presence of CH3···O hydrogen bond, since other factors like Coulombic interactions, van der Waals repulsions, and van der Waals attractions could be excluded from being the main factor for the stabilization.
Photoinduced Substitution Reaction Initiated by Electron-Transfer. Photochemical Reaction of 2,3-Dichloro-1,4-naphthoquinone with Thiophenes
Authors: Maruyama Kazuhiro , Tamiaki Hitoshi 
Published: July 2006

Abstract
Photochemical reaction of 2,3-dichloro-1,4-naphthoquinone (1) with thiophenes 2 afforded 2-chloro-3-(2-thienyl)-1,4-naphthoquinones. The reaction might be initiated by the photoelectron transfer from 2 to 1, resulting in the formation of combined products via recombination of the formed ion radicals 1\ewdot and 2\underset.+ by accompanying elimination of chloro and hydro radicals. In the photoreaction, reactivity of 2 was estimated from the observed oxidation potentials of 2 and the calculated electron densities in 2\underset.+.
Stereoselective Synthesis of (E)- or (Z)-α-Alkylidene-γ-butyrolactone from γ-Butyrolactone and Bis[ethoxy(thiocarbonyl)] Disulfide and Mechanistic Studies of the Effect of Metal Complexes on the Stereoselection
Authors: Matsui Syuichi 
Published: July 2006

Abstract
Treatment of γ-butyrolactone with bis[ethoxy(thiocarbonyl)] disulfide in the presence of 2.2 equiv of lithium diisopropylamide (LDA) produced lithium enolate of O-ethyl S-(tetrahydro-2-oxo-3-furanyl) dithiocarbonate, which reacted with an aldehyde to afford exclusively (E)-α-alkylidene-γ-butyrolactone. Interestingly, when the reaction was quenched below −20 °C or when it was carried out in the presence of metal complex such as zinc chloride, copper(I) iodide, or tributyltin chloride, (Z)-α-alkylidene-γ-butyrolactone was obtained as the major product. The stereoselectivity of this reaction was sensitive to the reaction temperature and the metal cation employed.
Stereoelectronic Control in the Hydrolysis of RNA by Imidazole
Authors: Taira Kazunari 
Published: July 2006

Abstract
The cleavage of poly(uridylic acid) by imidazole buffer was studied recently by Breslow and Labelle, and a bell-shaped profile was observed for the rate vs. buffer protonation state. The reaction, however, was kinetically first-order in buffer (R. Breslow and M. Labelle, J. Am. Chem. Soc., 108, 2655 (1986)). The sequential base-acid mechanism proposed by those authors is in agreement with the expectation based on the stereoelectronic effects. In addition, the alternative sequential acid-base mechanism, which could not be excluded on the basis of their kinetic data, may be excluded based on the stereoelectronic considerations.
Inductively Coupled Plasma Atomic Emission Spectrometric Determination of Copper by Suction-Flow On-Line Liquid–Liquid Extraction of Its Macrocyclic Dioxotetramine Chelate
Authors: Kumamaru Takahiro , Nitta Yoko , Matsuo Hiroshi , Kimura Eiichi 
Published: July 2006

Abstract
The flow manifold described permits suctionflow liquid–liquid extraction of copper(II) in a discrete aqueous sample as its macrocyclic dioxotetramine (6-hexadecyl-1,4,8,11-tetraazacyclotetradecane-5,7-dione, HDC) chelate into chloroform. The organic extract is successively fed into the inductively coupled plasma by a peristaltic pump. The detection limit is 1.5 ng cm−3 copper(II) and the relative standard deviation is 2.2% (n=10) for 100 ng cm−3 copper(II).
Preparation of Isoxazolines by Thermolysis of Ethyl 2-Nitroalkanoates in the Presence of Dipolarophiles
Authors: Shimizu Tomio , Hayashi Yoshiyuki , Shibafuchi Hiroshi , Teramura Kazuhiro 
Published: July 2006

Abstract
3-Alkyl-2-isoxazolines and 3-alkylisoxazole were prepared by thermolysis of ethyl 2-nitroalkanoates at about 230 °C in the presence of dipolarophiles.
Pressure Effect in Syngas Conversion to Ethylene Glycol. A Behavior of Rhodium–Tributylphosphine–N-Methylpyrrolidone System under 1000 atm
Authors: Murata Kazuhisa , Matsuda Akio , Masuda Takashi , Watanabe Eiichi , Wada Keisuke 
Published: July 2006

Abstract
In syngas (CO+H2) conversion to ethylene glycol (EG), rhodium catalyst modified by tributylphosphine (PnBu3) was found to be ca. 20 times more active under 1000 atm at 210 °C than under 500 atm. This unusual pressure effect was discussed on the basis of IR spectral data.
Kinetic Study of Liquid-Phase Esterification with Sulfonic Acid Cation-Exchange Resin of the Macroreticular Type. II. Solvent Effects on Resin Catalysis
Authors: Shimizu Shoichi , Hirai Choichiro 
Published: July 2006

Abstract
The rates of the esterification of octanoic acid with 1-butanol catalyzed by macroreticular sulfonated ion-exchange resin in the presence of various organic solvents and water were measured by the use of a batch reactor. The solvent effects on the rate were investigated by applying the heterogeneous-pseudohomogeneous reaction mechanism. From these results, it was found that the effects can be quantitatively estimated by means of the magnitude of the equilibrium constants, Ksol(S), for the solvent-separated ion-pair formations, which are due to the interaction of the sulfo groups in the resin with the solvents. The correlations of the Ksol(S) value with the physical properties, μ and ε; the solvatochromic parameters, \boldmathπ*, \boldmathα, and \boldmathβ, and Gutmann’s parameters, ANE and DNB, have been examined by using linear regression analysis methods. The results of the correlations in which the protic solvents have been excluded suggest that the positions of the equilibria of solvent-separated ion-pair formations depend mainly on the electron-donor property of the solvents; that is to say, the solvents with a strong donor property diminish the number of un-ionized sulfo groups which act as catalytic species for the heterogeneous reaction.
Stabilization of Platinum-Loaded CdS Photocatalyst by Addition of EDTA
Authors: Matsumura Michio , Ohnishi Hideyuki , Hanafusa Koji , Tsubomura Hiroshi 
Published: July 2006

Abstract
The photocatalytic activity of platinum-loaded CdS powder in sulfite solutions declined by illumination over 200 h, and became half the initial activity at 600 h. By addition of small amount (2 mM) of ethylenediaminetetraacetic acid (EDTA) to the solution, however, the photocatalyst was guarded from deterioration. The effect of EDTA is to prevent the platinum part of photocatalyst from the impurity metal deposition by forming stable metal-EDTA complexes in the solution. The reactivities of sulfite ions, EDTA, and metal-EDTA complexes on illuminated CdS are examined electrochemically by use of CdS-sinter electrodes.
Characteristic Polynomial Expression and Integral Expression for Imaginary Bond–Bond Polarizability. Rules for London Susceptibility and for Ring Current
Authors: Mizoguchi Noriyuki 
Published: July 2006

Abstract
The McWeeny theory for calculating magnetic properties of conjugated hydrocarbons is studied from a graph-theoretical point of view. Imaginary bond–bond polarizability is expressed in terms of characteristic polynomial. The expression clarifies the dependence of imaginary bond–bond polarizability on the structure. It is shown that the expression enables one easily to derive the equations for the quantity proved in two previous papers. The characteristic polynomial expression for imaginary bond–bond polarizability is rewritten in Coulson’s integral form. The rules for London susceptibility and for ring current are proved from the integral expression.
The Effect of the Chain Length and the End-Groups on the Epitaxial Growth of Long-Chain Molecules
Authors: Ueda Yasukiyo 
Published: July 2006

Abstract
Five paraffins (C30–C44) and three linear compounds with polar end-groups, such as hydroxyl, methyl-ester, and carboxyl groups, were deposited on the cleavage surface of an alkali halide crystal in vacuo. Paraffin films deposited on the substrate took the same crystal structure and molecular orientation, independent of the number of carbon atoms in the chain. In the case of derivatives, the morphology and orientation of the crystals, however, differed with the end-groups. The (110) planes of paraffins, alcohol, and methyl-ester crystals were oriented parallel to the substrate (001) plane, and their c-axes were parallel to the [110] direction of the substrate crystal. On the other hand, the (001) plane of the acid crystal lay parallel to the substrate surface, so that the c-axis of the crystal was oblique to the substrate surface. The epitaxial growth of linear molecules with different end-groups was explained by the difference in the interaction between the end-groups and the substrate.
Microenvironmental Effects of Water-Soluble Polymers on the Chemiluminescence of Luminol and Its Analogs
Authors: Karatani Hajime 
Published: July 2006

Abstract
The effects of water-soluble polymers(WSPs), such as bovine serum albumin(BSA) and polyethylenimine(PEI), on chemiluminescence(CL) in an aqueous solution have been studied. The CL emission, particularly in the initial stage of the CL reaction, was strongly enhanced by increasing the concentrations of these WSPs. This was attributed to the acceleration of the chemical reactions prior to the formation of the light-emitting species. BSA was also peculiar in that it could enhance CL under neutral pH conditions. It was suggested that these WSPs offered hydrophobic and basic microenvironments well suited to the CL reaction.
The Wetting of an Alumina Substrate by Liquid Silver
Authors: Ushio Masumi , Sumiyoshi Yoshihiro 
Published: July 2006

Abstract
The wetting of the Al2O3 substrate by liquid silver was investigated by means of the sessile-drop technique in an atmosphere of argon. An empirical relation was established between the contact angle and the temperature or surface tension of the liquid drop by the use of the diameter and the height of the sessile drop. The contact angle was constant as the time increased while it decreased linearly with the increase in the temperature. The variation in the contact angle with the temperature is correlated with the surface tension of the sessile drop. The critical surface tension (γc) of Al2O3 is 361 dyn cm−1, while the surface tension of liquid silver at 0 K is 790 dyn cm−1.
Prediction of Dissociation Constants of Ammonium Ion in Artificial Seawaters and in Concentrated Sodium Chloride Solutions
Authors: Maeda Masunobu , Hayashi Masato , Ikeda Shoichiro , Kinjo Yoshiaki , Ito Kaname 
Published: July 2006

Abstract
The dissociation constants of ammonium ion were determined at 25°C by potentiometry with glass and ammonium-ion-selective electrodes in artificial seawaters at various salinities (25–45\ extperthousand) and in concentrated sodium chloride aqueous solutions (0.72–3.2 mol kg−1). The activity coefficients of ammonia in sodium chloride solutions of the same ionic strengths as those of the artificial seawaters and in the concentrated sodium chloride solutions, which were used for the theoretical estimation of the dissociation constants, were measured by a transpiration method. The dissociation constants were theoretically evaluated in terms of the ionic interaction model developed by Pitzer and co-workers, and compared with the experimental ones. The predicted dissociation constants showed a good agreement with the observed ones.
Correlation of Oxidation and Reduction Potentials of Reactants with Product Distribution in the Reactions of Various Organomagnesium Reagents with Aromatic Carbonyl and Nitro Compounds
Authors: Okubo Masao , Tsutsumi Toshiki , Matsuo K\={o}ji 
Published: July 2006

Abstract
In the electron transfer initiated fifteen reactions of five organomagnesium reagents, a semiquantitative relationship between the product distribution and the electron-donating and -accepting abilities (EDA and EAA) of reactants was obtained. The EDA was estimated by cyclic voltammetry of oxidation peak potentials of reagents and/or by the product distribution in their reactions, the decreasing order of EDA being: ArMgBr&gt;ArSMgBr&gt;ArNHMgBr&gt;ArN(MgBr)2&gt;ArOMgBr. The EAA of six quinones, eight nitroarenes, eleven aromatic ketones and an imine, and five azoxyarenes were similarly estimated by their reduction potentials (redox) in THF. The values of differences between the oxidation peak and reduction potentials were taken as an estimate of the relative efficiency of electron transfer, and were correlated to the distribution of normal (addition, condensation, replacement, and azoxy-deoxygenation) and abnormal (radical) products. Some exceptional cases were explained by modifying EDA and/or EAA based on the effect of coordination of substrate’s oxygen to reagent’s Mg atom.
Syntheses of Optically Active Pentaacetates of Pseudo-β-l-allopyranose and Pseudo-α-d-mannopyranose
Authors: Tadano Kin-ichi , Fukabori Chiyoko , Miyazaki Masayuki , Kimura Hiroshi , Suami Tetsuo 
Published: July 2006

Abstract
Diisobutylaluminium hydride reduction of d-glucose-derived chiral synthon, (1R,6R,8R,9R)-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]non-4-en-3-one (1), gave a 7:1 mixture of (1R,3S,6R,8R,9R)- and (1R,3R,6R,8R,9R)-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]non-4-en-3-ol, (2) and (2′). Introduction of cis-diol to the double bond of 3-O-acetyl derivatives of 2 and 2′ by osmium tetraoxide oxidation provided the diastereomeric mixture of (1R,3S,4R,5S,6S,8R,9R)-3-acetoxy-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonane-4,5-diol (5) and (1R,3R,4S,5R,6S,8R,9R) diastereomer. Compound 5 was transformed to optically active pseudo-β-l-allopyranose effectively via (1R)-1-[(1S,2S,3S,4R,5S)-3,4,5-tris(benzyloxy)-2-hydroxycyclohexyl]-1,2-ethanediol (9). Cyclohexanecarbaldehyde formed by glycol cleavage of 9 was treated with methanesulfonyl chloride and reduced with lithium aluminium hydride to give (3S,4R,5S)-3,4,5-tris(benzyloxy)-1-cyclohexene-1-methanol (13). Compound 13 was efficiently converted to pseudo-α-d-mannopyranose pentaacetate by stereoselective hydroboration as a key reaction. The Wharton reaction of (1R,4S,5S,6S,8R,9R)-4,5-epoxy-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]nonan-3-one derived from 1 gave(1R,5R,6S,8R,9R)-8,9-isopropylidenedioxy-7-oxabicyclo[4.3.0]non-3-en-5-ol, into which (3S,4S)-diol was stereoselectively introduced by oxidation with osmium tetraoxide.
A Solvent-Extraction Study of the Hydrolysis of Tracer Concentrations of Bismuth(III) in Chloride Solutions
Authors: Suganuma Hideo , Shimizu Itaru , Hataye Itsuhachiro 
Published: July 2006

Abstract
The backward solvent extraction with dithizone(H2dz)–CCl4 solutions was used to examine the chemical species of bismuth(III) in 1 mol dm−3 of a (H,Na)Cl solution. A tracer concentration of bismuth(III) (ca. 10−11 mol dm−3) was found to exist mainly in the form of [BiCl5]2−, [BiCl5(OH)]3−, [BiCl4(OH)]2−, and [BiCl3(OH)3]3− in the (H,Na)Cl solutions. The constants of the successive hydrolysis, β1, β2, and β3, were calculated by using the distribution data. The resulting logβ1, logβ2, and logβ3 values were 10.9, 17.5, and 30.2 respectively. The chemical composition of the extracted species was most probably [Bi(Hdz)3].
Sulfur Contents of Volcanic Rocks in Japan
Authors: Arikawa Yoshiko 
Published: July 2006

Abstract
The total sulfur content was determined for 140 samples of Japanese volcanic rock by the mercury(II) thiocyanate photometric method of hydrogen sulfide formed by a wet reduction of the sample by tin(II)–strong phosphoric acid. Though determined values are widely scattered from 5390 down to 10 ppm (or less), the cumulative frequency distribution of the sulfur contents shows lognormality. The geometric and arithmetic means are 26 ppm (mg kg−1) and 116 ppm, respectively. The alkaline rocks have high sulfur contents, the geometric mean of which is 62 ppm. Little significant difference was observed among the rhyolitic rock, the andesite and the trachyte, and the basaltic rock. Japanese and foreign standard rock samples were analyzed for sulfur. Almost all results were in good agreement with those obtained by other authors. In this case foreign standard samples also have higher sulfur contents than those of Japanese samples. The fact that the sulfur contents of Japanese volcanic rocks are lower than the previously accepted values seems to be characteristic of the islands arc of volcanism.
Raman Spectra of Tris(bidentate)cobalt(III) Complexes Containing 1,3-Propanediamine and β-Alaninate
Authors: Kawamoto Tatsuya , Einaga Hisahiko , Hidaka Jinsai 
Published: July 2006

Abstract
The Raman spectra of the tris(bidentate)cobalt(III) complexes containing the six-membered tn and/or β-ala chelate ring, where tn and β-ala denote 1,3-propanediamine and β-alaninate respectively, were measured in order to investigate the relation between the Raman spectra and the structures of the complexes. The Raman bands can be classified into four vibration modes: A totally symmetric stretching vibration mode in the 440–640 cm−1 region, a stretching vibration mode excluding the totally symmetric one in the 380–480 cm−1 region, a metal-ligand skeletal bending deformation mode in the 260–400 cm−1 region, and a chelate ring deformation mode in the 220–290 cm−1 region. The present complexes characteristically exhibited more Raman bands than the complexes with the five-membered chelate rings in the totally symmetric stretching vibration mode. For the [Co(β-ala)2(tn)]+ complex, the three geometrical isomers, trans(O), C2-cis(O), and C1-cis(O), which were prepared for the first time, each exhibited characteristic Raman spectral features.
The Complexing of the Magnesium and Barium Ions in Acetonitrile with Other Solvents. Investigation by the Use of a Polyacrylamide-Tetraethylene Glycol Monododecyl Ether Membrane Ion-Selective Electrode
Authors: Nakamura Toshio , Higuchi Hisakazu , Izutsu Kosuke 
Published: July 2006

Abstract
The complexations of magnesium and barium ions in acetonitrile with DMF, DMSO, and HMPA were studied potentiometrically by the use of an organic polymer membrane electrode. The formation constants for 1:1 complexes of magnesium and barium ions, respectively, were 2.1×102 and 19 with DMF, 4.5×102 and 41 with DMSO, and (5.5×103) and 1.6×103 with HMPA. The roles of the basicity of the complexing solvent, crystallographic radius, and charge of the cations are discussed briefly.
The Crystal Structure of Phenanthrene: Picric Acid Molecular Complex
Authors: Yamaguchi Shin-ichi , Goto Motoaki , Takayanagi Hiroaki , Ogura Haruo 
Published: July 2006

Abstract
The crystal structure of phenanthrene:picric acid molecular complex was determined by X-ray crystal analysis. Phenanthrene and picric acid molecules are stacked alternately along the c-axis, making their molecular planes parallel to each other. The intramolecular hydrogen bonding exists in a picric acid.
Shape Selectivity of ZSM-5 Type Zeolite for Alkylation of Ethylbenzene with Ethanol
Authors: Kim Jong-Ho , Namba Seitaro , Yashima Tatsuaki 
Published: July 2006

Abstract
The alkylation of ethylbenzene with ethanol on ZSM-5 zeolites was studied at 673 K. The primary product in this alkylation on HZSM-5 catalyst was only p-diethylbenzene because of the transition-state selectivity. Therefore, the isomerization of p-diethylbenzene has to be restrained for the selective formation of p-diethylbenzene. The modified HZSM-5 catalysts with oxide of magnesium, phosphorus or boron showed much higher para-selectivity than the parent HZSM-5. The modification reduced not only the effective pore dimension of HZSM-5 but also the amount of strong acid sites. We claim that the absence of strong acid sites is necessary rather than the narrowness of pores for the suppression of the isomerization of p-diethylbenzene produced as a primary product.
Photooxidation of the Evaporated Films of Polycyclic Aromatic Hydrocarbons Studied by X-Ray Photoelectron Spectroscopy
Authors: Yamada Masamichi , Ikemoto Isao , Kuroda Haruo 
Published: July 2006

Abstract
Photooxidations of the evaporated films of rubrene, naphthacene, and pentacene were investigated by means of X-ray photoelectron spectroscopy. A rubrene film was found to be photooxidized far more easily than a naphthacene film although the molecules of rubrene and naphthacene in solution are known to be almost equally reactive for photooxidation. Although pentacene is photooxidized very easily in solution, the oxidation rate of a pentacene film was little enhanced by the light irradiation. Discussion is given on these behaviors of the evaporated films by considering the molecular packing in the solid state and the mechanism of photooxidation.
The Effects of the Sol–Gel Transition of Alginates on Effective Charge Densities
Authors: Yonese Masakatsu , Baba Kazuhiko , Kishimoto Hiroshi 
Published: July 2006

Abstract
The counterion binding properties of alginate (Alg) sol and gel were studied by using the membrane potential method, in which membranes were constructed of an Alg layer sandwiched between supporting films. The concentrations of Alg WAlg ranged from 0.0025 to 0.0063 g cm−3, and the membrane potentials were measured in NaCl, MgCl2, and CaCl2 solutions. The effective charge densities of Alg (θ*2) were obtained by curve fittings with the theoretical values of the multimembrane potentials. The ratios of θ*2 to the concentration of uronate units θ0 were found not to depend on WAlg; their mean values were 0.45, 0.28, and 0.12 for Na-, Mg-, and CaAlg. The results of Na- and MgAlg in the sol state were bigger than Manning’s theoretical values. The much smaller values of CaAlg in the gel state than MgAlg in the sol state showed that the Ca ion binding was enhanced by the gellation not only in the junction, but also in the networks.