bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solvent Induced Structural Change of 18-Crown-6 Complexed Ion Pair with 9-Fluorenone Anion Radical as Studied by ESR Spectroscopy
Authors: Nakamura Kazuo 
Published: July 2006

Abstract
ESR spectra of the ion pairs of the 9-fluorenone anion radical with 18-crown-6 complexed sodium and potassium ions were examined. From the dependence of the carbonyl 13C hyperfine splitting of the fluorenone anion on temperature and solvent, it was conclude that an ethereal solvent molecule can solvate the crown complexed cation on the opposite side of the anion with respect to the plane of the crown ether ring, equilibrium taking place between the solvated and unsolvated ion pairs in ethereal solution. The unsolvated species of both the potassium and the sodium ion pairs and the solvated species of the sodium ion pair are classified as contact ion pairs, the solvated species of the potassium ion pair a crown separated one. The equilibrium constant between the solvated and unsolvated ion pairs changes with temperature and solvent. From this change the enthalpy changes of solvation process were estimated for several solvents.
Direct Measurement of Interaction Energy between Solids and Gases. VII. Heats of Adsorption of Carbon Monoxide on Cu(II)-exchanged Zeolites Y
Authors: Miwa Yoji , Tsutsumi Kazuo , Takahashi Hiroshi 
Published: July 2006

Abstract
Differential heats of the adsorption of carbon monoxide on Cu(II)Y zeolites were calorimetrically determined. The heat of adsorption was larger on Cu(II)Y zeolites than on the NaY zeolite, and increased with the degree of Cu(II) ion-exchange. Repeated adsorption-desorption measurements revealed an increase in the heat of adsorption, which is considered to be due mainly to the migration of copper(II) ions from inaccessible sites for carbon monoxide to accessible ones in the process of adsorption-desorption.
Outer-sphere Assocation of Some Achiral Cobalt (III)–Amine Complexes as Measured by Their Induced Circular Dichroism Spectra in Aqueous (R,R)-Tartrate Solutions
Authors: Miyoshi Katsuhiko , Oh Chang Eon , Yoneda Hayami 
Published: July 2006

Abstract
Outer-sphere association constants KA of inherently achiral cobalt(III)–amine complexes, [Co(NH3)6]3+, [Co(NH3)4(en)]3+, and trans-[Co(NH3)2(en)2]3+ with (R,R)-tartrate anion (d-tart2−) were determined by measuring their weak CD spectra induced when they were dissolved in aqueous d-tart2− solutions at 25 °C. It was found that the KA values are not so different among these three complexes, whereas their molar CD intensity ΔεMX gained by the association with d-tart2− increases with increasing number of their chelate rings. This was tentatively interpreted to mean that the distortion of the Co(III)–N bonds brought about by outer-sphere association with chiral d-tart2− is greater when bidentate ligands (en) are coordinated than when unidentate ones (NH3) are, i.e., when the complex has more chelate rings. Also it was found that the KA value thus obtained for [Co(NH3)6]3+ is much smaller than that determined by measuring the magnitude of its charge-transfer band which newly appears upon the addition of d-tart2−. From the above finding and other experimental results, it was suggested that induced CD is well developed in these achiral amine complexes when the two hydroxyl oxygen atoms of d-tart2− simultaneously form hydrogen-bonds with amine protons of the ligands.
Kinetics of the Stereoselective Deuteration of Malonate Hydrogens in Some Bis(malonato)cobalt(III) Compounds and the Reversal of Stereoselectivity Induced by the Solution pH
Authors: Sakaguchi Ushio , Morito Kaiji , Yoneda Hayami 
Published: July 2006

Abstract
The deuteration rates at malonate methylene groups have been measured for several [Co(mal)2(N)2]− ions over the pD range of 2 to 9 at 36.4 °C, where mal=malonate ion, (N)2=ethylenediamine, cis-(NH3)2, 1,3-propanediamine, N,N′-dimethylethylenediamine, cis-(pyridine)2, and 1,10-phenanthroline. The malonate deuteration is acid-catalysed at pD less than about 4 and base-catalysed at higher pD in all the compounds. In the aminocontaining compounds (the first four compounds), the reaction proceeds stereoselectively in both high and low pD regions. Though the degree of the stereoselectivity depends upon the compound, the fast-exchanging hydrogen is, for all the amino-containing compounds, the one which is adjacent to the coordinating nitrogen atom. The mechanisms of acid- and base-catalysed deuteration, as well as the origin of the stereoselectivity, are discussed. For the ethylenediamine and cis-(NH3)2 compounds, reversal of the stereoselectivity takes place at around pD=8 and 9, respectively, and the fast-exchanging hydrogen becomes the one farthest apart from the coordinating nitrogen. Concomitant with this reversal, both malonate and amine exchange rates fall together. Thus, the rate of hydrogen-deuterium exchange at the NH3 groups does not show the usual first-order dependence upon the OD− concentration. These observations are explained by a mechanism in which equally reactive malonate and amine hydrogens compete for OD− catalyst.
Studies on Characteristics of Electron Capture Responses. IV. Carrier Gas Flow-rate Dependence of Electron Capture Coefficients
Authors: Takeuchi Masahiro 
Published: July 2006

Abstract
The electron capture coefficients, K, defined by Wentworth et al. were measured on several samples in various carrier gas flow-rates at the detector temperatures of 200–320 °C. The effect of the flow-rate on the value of K was considered. The results revealed that the flow-rate dependence of K for each sample was closely related to one of the three electron capture reaction processes. In a sample undergoing the non-dissociative electron capture reaction, the values of K were generally not affected by the flow-rate; they decreased slightly with increasing the flow-rate at higher temperatures. In a sample undergoing the dissociative electron capture reaction, the values of K increased significantly with increasing the flow-rate at all temperatures. In a sample undergoing the dissociative electron capture reaction through an anion radical intermediate, the values of K were slightly or not at all affected by the flow-rate at lower temperatures, but increased gradually with increasing the flow-rate at higher temperatures.
Formation of Hydrogen Peroxide by Two-stage Acid Hydrolysis of trans(NO2,O2)-[μ-Peroxo-bis{nitrtobis(ethylenediamine)cobalt(III)}] and Reaction Kinetics
Authors: Shibahara Takashi , Kuroya Hisao , Mori Masayasu 
Published: July 2006

Abstract
The aquation rate of trans(NO2,O2)-[(NO2)(en)2CoO2Co(en)2(NO2)]2+ has been measured in acidic aqueous solution at [H+]=0.003–0.25 M and I=0.50 M (LiClO4), the final products being trans-[Co(NO2)(OH2)(en)2]2+ and H2O2 in marked contrast to the acid decomposition of [(NH3)5CoO2Co(NH3)5]4+ where the final products are Co(II) and O2. The reaction consists of two stages, each of which has preequilibrium of protonation. The observed rate constants for the first and second stages are consistent with the formula, k1obsd=k1K1[H+]⁄(1+K1[H+]) (i=1, 2), indicating the existence of protonated reactive forms in both stages. The rate constants, activation parameters and equilibrium constants are k1=7.46 s−1 (25 °C), ΔH1\eweq=66.9±1.3 k J mol−1, ΔS1\eweq=−2.9±4.2 J K−1mol−1, and K1=3.44 M−1 (25 °C) for the first stage and k2=0.400 s−1 (25 °C), ΔH2\eweq=85.4±2.1 kJ mol−1, ΔS2\eweq=33.5±7.1 J K−1 mol−1, and K2=2.98 M−1 (25 °C) for the second stage. The solution of the reaction intermediate [Co(NO2)(O2H)(en)2]+ has been obtained by ion exchange technique and characterized by the UV and visible spectra. The factors which decide the reaction path are discussed.
Precise Determination of Dissolved Gases in Sea Water by Shipboard Gas Chromatography
Authors: Gamo Toshitaka , Horibe Yoshio 
Published: July 2006

Abstract
A gas chromatographic system is applied to shipboard measurement of dissolved argon, oxygen, nitrogen, and total inorganic carbon dioxide in sea water. Gases are stripped from acidified sea water with helium carrier gas, separated by passing through silica-gel and molecular sieve 5A columns, and subsequently analyzed with a thermal conductivity detector and an ultrasonic detector. Ca. 15 min is required to analyze a 3 cm3 sea water sample. Intercalibration by other analytical techniques for oxygen and total carbon dioxide confirmed the accuracy of this method. Vertical profiles of the gases in the Pacific Ocean demonstrate the merit of the method.
The Preparation of Vanadium Tetrachloride from Vanadium Dichloride Oxide and Vanadium Trichloride and the Hydrogen Reduction Process of Vanadium Tetrachloride
Authors: Yajima Akimasa , Matsuzaki Ryoko , Saeki Yuzo 
Published: July 2006

Abstract
The reactions of VCl2O and VCl3 with chlorine, and the reaction of VCl3O, formed by the chlorination of VCl2O, with chlorine in the presence of carbon were examined. The products formed by the reaction between gaseous VCl4 and hydrogen at various temperatures, and the behavior of VCl3 and VCl2 on heating in a hydrogen stream were examined. The reaction between VCl2O and chlorine occurs above ca. 120 °C and proceeds markedly above ca. 170 °C to form VCl3O. VCl4 can be obtained by passing the gaseous VCl3O together with chlorine through a carbon bed held at ca. 700 °C. The reaction between VCl3 and chlorine occurs above ca. 80 °C and proceeds markedly above ca. 170 °C to form VCl4. The hydrogen reduction process of VCl4 in the vapor phase may be represented as follows: The reaction between VCl4 and hydrogen, 2VCl4(g)+H2(g)→2VCl3(s)+2HCl(g), proceeds above ca. 500 °C to form VCl3. Subsequently, the hydrogen reduction of the VCl3, 2VCl3(s)+H2(g)→2VCl2(s)+2HCl(g), and the disproportionate of the VCl3, 2VCl3(s)→VCl2(s)+VCl4(g), proceed to form VCl2. Above ca. 620 °C, the reaction between the VCl2 and hydrogen, VCl2(s)+H2(g)→V(s)+2HCl(g), proceeds to form vanadium.
The Determination of the Oxidation States of Neptunium in Sodium Hydroxide Solutions by Adsorption on Zirconium(IV) Hydroxide
Authors: Shiokawa Yoshinobu , Sat\={o} Akiko , Suzuki Shin 
Published: July 2006

Abstract
An adsorption method for determining the distribution of the oxidation states of neptunium in sodium hydroxide solutions is proposed. In the range of sodium hydroxide concentrations of 1–2 M (1 M=1 mol dm−3), the Np(V) was almost entirely adsorbed on zirconium(IV) hydroxide, while both Np(VI) and Np(VII) remained in the supernatant. By means of this adsorption method, it was found that Np(V) in tracer quantities, though it was most stable in acidic or neutral solutions, was not the most stable state in sodium hydroxide solutions. Also, the oxidation and reduction of Np in sodium hydroxide solutions were investigated.
Indirect Spectrophotometric Determination of Phosphate Employing the Solubilization of Methylene Blue Molybdophosphate with Zephiramine
Authors: Shida Junichi , Matsuo Tsutomu 
Published: July 2006

Abstract
A highly sensitive indirect spectrophotometric method for phosphate was developed. The ion-association complex of molybdophosphate with Methylene Blue was precipitated in a nitric-acid medium. The complex was adsorbed on (1+4 v/v) cyclohexane–MIBK. The excess of Methylene Blue was removed by washing the organic phase with water. The complex was solubilized with a Zephiramine acidic aqueous solution. By measuring the absorbance of Methylene Blue in the aqueous solution at 660 nm, the phosphate was determined. The calibration curve was linear in the 0.31–3.1 μg range of phosphate, and the molar absorptivity was 2.5×105 l·mol−1·cm−1. The absorbance of the reagent blank was 0.019±0.001, and the recommended procedure was applied to the repetitive determination of 1.55 μg of phosphorus. The ten determinations produced a coefficient of variation of 1.6%. Arsenic, germanium and silicon, which form heteropolyacids like phosphorus, interfered seriously.
Preparation and Stereochemistry of Bis(1,10-phenanthroline)- and Bis(2,2′-bipyridine)chromium(III) Complexes Containing 2,2′-Bipyridine N,N′-Dioxide or Its 3,3′-Dimethyl Derivative
Authors: Kanno Hideaki , Kashiwabara Kazuo , Fujita Junnosuke 
Published: July 2006

Abstract
Bis(1,10-phenanthroline)- and bis(2,2′-bipyridine)chromium(III) complexes containing a seven-membered chelate ligand, 2,2′-bipyridine N,N′-dioxide(bpdo) or 3,3′-dimethyl-2,2′-bipyridine N,N′-dioxide(mbdo) were prepared. Each complex gave only one of two possible pairs of enantiomers resolved by SP-Sephadex column chromatography. On the basis of the circular dichroism spectra, molecular models, and recovery of the optically active free mbdo ligand from the resolved mbdo complexes, it was found that all the enantiomeric pairs consist of Δ(δ) and Λ(λ) isomers involving the skew dioxide chelate ligands in the ob configuration.
Steric Effect in Regioselective Cyclization of 3,4-Epoxy Alcohols to Oxetanes
Authors: Masamune Tadashi , Sato Shingo , Abiko Atsushi , Ono Mitsunori , Murai Akio 
Published: July 2006

Abstract
A number of 3,4-epoxy alcohols, involving critical structural factors for oxetane formation by intramolecular cyclization, were prepared and treated with base under aqueous (KOH in 75% aq DMSO) and anhydrous conditions (NaH in THF). The result of the reactions of cis- and trans-4,5-epoxy-2-rnethyl-2-undecanols, coupled with that of 1-(2,3-epoxybutyl)- and 1-(2,3-epoxy-3-methylbutyl)-1-cyclohexanols (1a and 1b), indicated that the regioselective oxetane formations of 3,4-epoxy alcohols with alkoxide anions are much insensitive to steric hindrance at the attacked oxirane rings, compared with the corresponding reactions with carbanions, while that of 1-(2,3-epoxypropyl)-1-cycloalkanols revealed that the relevant reactions depend on bulkiness of attacking alkoxide anions. Moreover, the result of the reactions of 1-(1,2-epoxycycloalkyl)-2-methyl-2-propanols under the aqueous conditions demonstrated that the oxetane formations are affected seriously by steric hindrance at the attacked oxirane rings, although the result was in striking contrast with the corresponding result with carbanions. On the other hand, the reactions of 3,4-epoxy alcohols under the anhydrous conditions proceeded in different manner, depending on the structures of the epoxides; namely, fragmentation took place as major reactions with some epoxides, while intramolecular cyclization occurred predominantly with other epoxides.
Synthesis, Absolute Configuration, and Chiroptical Property of (+)-cis-4b,5,9b,10-Tetrahydroindeno[2,1-a]indene-5,10-dione
Authors: Ogura Fumio , Nakao Akio , Nakagawa Masazumi 
Published: July 2006

Abstract
The title compound having the (4bS,9bS) configuration was prepared from (2S,3S)-(+)-2,3-diphenylsuccinic acid, and the circular dichroic property was discussed.
Low-temperature Photolysis of ortho-Substituted Azidobiphenyls. Formation of Phenazines from 2,2′-Diazidobiphenyls
Authors: Yabe Akira 
Published: July 2006

Abstract
It was found that the unexpected phenazines were formed as minor products by the low-temperature photolysis of 2,2′-diazidobiphenyls in a rigid matrix. The phenazine formation results from the 1,1′-C–C bond fission of the biphenyl nucleus and suggests the aziridine intermediates. The low-temperature photolysis of 2-azido-2′-methylbiphenyl and 2-azido-2′,4′,6′-trimethylbiphenyl leads to the triplet-derived phenanthridine derivatives as major products.
Photoreactions of Flavanones
Authors: Matsushima Ryoka , Kishimoto Tsuneo , Suzuki Morio , Morioka Motonobu , Mizuno Hideo 
Published: July 2006

Abstract
Parent and substituted flavanones undergo photochemical opening of the pyrone ring to give corresponding 2′-hydroxychalcones in benzene, pyridine, acetonitrile etc., the yields varying from 0 to 70% with substituents. The reaction is depressed by the addition of 1,3-pentadiene, nitrosobenzene, or acrylonitrile. On the other hand, flavanone and 4-chromanone undergo photoreduction in 2-propanol to give reductive coupling products and solvent adducts as isomeric mixtures. 7,8-Benzoflavanone does not undergo photoreduction in 2-propanol but the ring opening reaction instead. Mechanisms have been discussed in terms of the relative contribution and π,π* character in the lowest triplet states.
A Novel Synthesis of 2-(1-Imidazolyl)benzophenones
Authors: Kayama Yasutaka , Hara Takeshi , Sunami Tamiko 
Published: July 2006

Abstract
2-(1-Imidazolyl)benzophenones were prepared from 3-(2,2-dialkoxyethyl)-3,4-dihydro-4-hydroxy-4-phenylquinazolines and a corresponding 4-alkoxy derivative by heating in formic acid or in sulfuric acid-ethanol.
The Chemical Conversion of the Photo-dimer of 2-Acetyl-5-methyl-1,4-benzoquinone. The Determination of the Regiochemistry of the Dimer
Authors: Miyagi Yo , Maruyama Kazuhiro , Yoshimoto Sachiko 
Published: July 2006

Abstract
From the photo-dimer (2a) of 2-acetyl-5-methyl-1,4-benzoquinone, mono- and diacetyl derivatives and 2,6-dimethyl-1,4,5,8,9-pentaacetoxyphenanthrene (3) were prepared. 3 was oxidized to 2,6-dimethyl-1,4,5,8-tetraacetoxy-9,10-phenanthrenequinone (4). The acetoxyl groups of 4 were partly deuterated to assign their 1H NMR signals. A series of chemical conversions of 2a to 4 via 3 unambiguously clarified the regiochemistry of 2a.
Nuclear Magnetic Resonance Studies of Hydrosilanes. III. A Correlation of Hammett σ Constants with 29Si–H Coupling Constants for Substituted Phenoxy- and (Phenylthio)dimethylsilanes
Authors: Watanabe Hamao , Akaba Ryoichi , Iezumi Takao , Nagai Yoichiro 
Published: July 2006

Abstract
The 29Si–H coupling constants and Si–H chemical shifts have been determined for a series of substituted phenoxy- and (phenylthio)dimethylsilanes. The J(29Si–H) values are shown to be correlated well with the Hammett σ constants for the substituent on benzene ring in compounds Ar–Y–SiMe2H, where Y=O and S. In comparison with the data for the analogs of the other types of organodimethylsilanes, such as aryldimethylsilanes, substituted benzyldimethylsilanes, and aryltetramethyldisilanes, the present results are discussed on the basis of the substituent effects through the intervening oxygen and sulfur. The transmission efficiency of Y was in the order, S&gt;CH2≈SiMe2&gt;O. For the series of (phenylthio)dimethylsilanes, the J(29Si–H) values observed were larger than those for the predicted ones. This deviation was interpreted in terms of the sulfur d-orbital participation via the electron-acceptor, “σ-π” conjugation.
Removal and Recovery of Organic Pollutants from Aquatic Environment. V. Crosslinked Poly(hydroxystyrene) as a Polymeric Adsorbent for Removal and Recovery of ε-Caprolactam from Aqueous Solution
Authors: Kawabata Nariyoshi , Taketani Yukihiko 
Published: July 2006

Abstract
Crosslinked poly(hydroxystyrene) (PHS resin) was found to be useful as a polymeric adsorbent for removal and recovery of ε-caprolactam from aqueous solution. The breakthrough capacity of PHS resins with &lt;1-mg/l leakage in the effluent was 50–90 mg/dry g, which was scarcely affected by the presence of hydrochloric acid, sodium hydroxide, and inorganic salts such as sodium chloride, potassium chloride, calcium chloride, and magnesium chloride. Elution of the adsorbed ε-caprolactam from PHS resin was easily accomplished by a simple treatment with methanol, and PHS resin was efficiently regenerated. ε-Caprolactam was concentrated into 10–30 g/l solution.
Assignment of Fundamental Vibrations of N,N′-Dimethylthiourea
Authors: Devi Kolar Ramakrishnaiaa Gayathri , Sathyanarayana Dixit Narayanarao 
Published: July 2006

Abstract
The infrared spectra of symmetric N,N′-dimethylthiourea (s-DMTU) and its N-deuterated (s-DMTU-d2) species have been measured. The fundamental frequencies have been assigned by comparison with the assignments in structurally related molecules and the infrared band shifts on N-deuteration, S-methylation, available Raman data and with the aid of theoretical band assignments from normal coordinate treatments for s-DMTU-d0 and -d2. A force field is derived for s-DMTU by transferring the force constants chiefly from N-methylthiourea and the subsequent refinement of the force constants by a least squares procedure.
Synthesis of Some Disperse Anthraquinone Dyes
Authors: Metwally Saoud A M , Youssef Mohamed S K , Younes Mansour I 
Published: July 2006

Abstract
1-Hydroxy- and/or 1-aminoanthraquinones was allowed to react with formaldehyde in an alkaline medium to give 1-hydroxy- or 1-amino-2-hydroxymethyl-9,10-anthracenediols, which gave by air oxidation, (hydroxymethyl) anthraquinone derivatives. Interaction of 1-amino-2-(hydroxymethyl) anthraquinone or its 4-bromo derivative with carbonyl compounds in the presence of an acid catalyst gave 1,3-oxazine derivatives (2). The methylene group in position-2 of the 1,3-oxazine ring was found to be highly reactive and reacted with carbonyl compounds to form the corresponding 2-arylmethylene derivatives. Selective oxidation of dimethyloxazine derivatives with SeO2 gave the corresponding dialdehyde, which interacted with aromatic amines to give the corresponding Schiff’s bases. The bromine atom in the 6-position of 2 was easily replaced by aromatic amines to give blue disperse dyes.
Interaction between Aromatics and Zinc Chloride. II. The Formation of σ-Complexes and Cation Radicals on Supported Zinc Chloride
Authors: Morita Mikio , Hirosawa Kunio , Sato Toshio , Ouchi Koji 
Published: July 2006

Abstract
Anhydrous zinc chloride supported in the solid state was found to produce colored intermediates by reactions with aromatics (anthracene, naphthacene, pentacene, pyrene, pelyrene, and chrysene) at 60 °C. The measurements of their electronic absorption spectra and ESR spectra confirmed that these were the same aromatics-zinc chloride σ-complexes and aromatics cation radicals as those formed in molten zinc chloride.
Relative Electron-capture Efficiency of Disubstituted Benzene in γ-Irradiated MTHF Glass at 77 K
Authors: Shimokawa Toshinari 
Published: July 2006

Abstract
The relative electron-capture efficiencies of disubstituted benzenes were measured by a competitive method. It was found that the efficiencies of the disubstituted benzenes are correlated with the reactivity towards nucleophilic species as expressed by Hammett’s substituent constant. The logarithmic values of the efficiency are roughly proportional to the polarographic half-wave reduction potentials and to the electron affinities.
The Hydrolytic Rate of Barbituric Acid and the Extrathermodynamic Relationship
Authors: Asada Shozo , Yamamoto Midori , Nishijo Jujiro 
Published: July 2006

Abstract
The enthalpy-entropy relationship of activation was subjected to discussion in connection with the alkaline hydrolysis of 10 barbituric acids. The extrathermodynamic linear equation was derived by using several parameters; the dissociation constant (pK), the 13C shift value [δc(5)] at the 5-position of the ring, and/ or the molecular connectivity index (χ).
Mössbauer Effect in Fluorotrimethyltin(IV)
Authors: Negita Hisao , Boku Ryukei , Sugiya Masahiro , Ichiba Sumio 
Published: July 2006

Abstract
The angular dependent Mossbauer spectra of 119Sn in needle crystals of fluorotrimethyltin(IV) were studied at 110 K. The principal axis of the electric-field gradient was observed at about 20° from the a axis. 19F NMR spectra of the solid were also studied. From the temperature dependence of the linewidth, the activation energy for the motion of the F atom was estimated to be 6.7±1.3 kJ mol−1.