bluuebunny/crossref_metadata_2025 huggingface dataset:
The Synthesis of 2,5-Bis(p-methoxycinnamoyl)-1,3,4,6,7,8- and 4,5-Bis(p-methoxycinnamoyl)-1,2,3,6,7,8-hexamethoxyxanthene
Authors: Obara Heitaro , Onodera Jun-ichi , Saito Takashi , Sato Shingo , Shibata Tsutomu , Shibayama Kimio
Published: July 2006

In connection with studies of the structure of carthamin derivatives, 2,5-bis(p-methoxycinnamoyl)-1,3,4,6,7,8- and 4,5-bis(p-methoxycinnamoyl)-1,2,3,6,7,8-hexamethoxyxanthene were synthesized. The comparison of these two hexamethoxyxanthenes with carthamin derivatives is described.
Low-temperature Reaction of gem-Dihalocyclopropanes with Activated Magnesium
Authors: Ando Teiichi , Muranaka Takeshi , Ishihara Takashi
Published: July 2006

The reaction of 7-bromo-7-chlorobicyclo[4.1.0] heptane and 7-bromo-7-fluorobicyclo[4.1.0] heptane with activated magnesium in THF at −50 to −40 °C gave 7-bromobicyclo[4.1.0] heptane, in addition to 7-chloro- and 7-fluorobicyclo[4.1.0] heptane, respectively.
Use of 1,8-Diazabicyclo[5.4.0]undec-7-ene in Preparation of Trimethylsilyl Enol Ethers and Trimethylsilylacetylenes
Authors: Taniguchi Yoshiyuki , Inanaga Junji , Yamaguchi Masaru
Published: July 2006

Trimethylsilyl enol ethers were prepared by using a combination of chlorotrimethylsilane and 1,8-diazabicyclo[5.4.0]undec-7-ene in good yields. Trimethylsilylation of acetylenes was also achieved with the same reagents in the presence of silver salt as catalyst.
The Effect of Hydration on the Thermal Stability of Ovalbumin as Measured by Means of Differential Scanning Calorimetry
Authors: Fujita Yukihisa , Noda Yukinao
Published: July 2006

The thermal denaturation of ovalbumin (egg albumin) was investigated by means of differential scanning calorimetry in the water-content range from 0.11 to 1.15 g of water per g of protein. At water contents above 0.76 g/g, the temperature, Td, and the enthalpy, ΔHd, of denaturation were scarcely dependent at all on the water content. At lower water contents, however, both Td and ΔHd showed a marked dependence on the water content. The degree of the hydration dependence of the Td and ΔHd suggested that the amount of water required to hydrate ovalbumin was 0.76 g/g and that at least two types of the hydration phase contributed to the thermal stability of the protein.
1-Chloro-1,3-butadiene Copolymers. III. Reactivity of 1-Chloro-1,3-butadiene in Radical Copolymerizations
Authors: Kohjiya Shinzo , Takeuchi Hideo , Kawamoto Kohshi , Yamashita Shinzo
Published: July 2006

Radical copolymerizations of 1-chloro-1,3-butadiene (CB) were carried out with styrene (St), 1,3-butadiene (Bd), or chloroprene (Cp) in toluene at 70 °C by AIBN. The monomer reactivity ratios are found as follows: rCB=1.21±0.10, rSt=0.10±0.03; rCB=0.27±0.02, rBd=0.56±0.03. Copolymerization of CB and Cp showed CB was much less reactive than Cp. The Q and e values of CB were calculated to be 3.13 and +0.65, respectively. 1H NMR and IR of poly(CB-co-St) showed 60% of CB units are of 1,4-configuration and the rest 3,4-configuration.
The Hartree-Fock and Electron-Hole Potential Methods from a Hypervirial Theorem Standpoint
Authors: Isihara Makoto
Published: July 2006

The hypervirial theorem is introduced in the second quantized expanded form, and utilized for reviewing the Hartree-Fock and electron-hole potential methods. A possibility of going beyond the latter is suggested within the scope of handy methods. Brillouin’s and the extended Brillouin’s theorems are shown to be contained in the hypervirial theorem.
Mass-spectrometric Study of the Vaporization of Magnesium Oxide from Magnesium Aluminate Spinel
Authors: Sasamoto Tadashi , Hara Hiroshi , Sata Toshiyuki
Published: July 2006

The partial vapor pressures of Mg(g) over the spinel solid solution system, MgO·nAl2O3(n=1.0, 2.0, and 2.8), have been measured by the mass-spectrometric Knudsen-cell method. In the temperature range from 1850 to 2300 K, the pressures are described by these equations:

log[P(Mg,g)over 1.0-spinel/atm]=7.72±0.24−(26900±490)⁄T,

log[P(Mg,g)over 2.0-spinel/atm]=7.72±0.32−(27400±670)⁄T,

log[P(Mg,g)over 2.8-spinel/atm]=7.78±0.42−(27900±1220)⁄T.

These observed values were discussed in comparison with the calculated ones obtained by an approximate thermodynamic treatment of an ionic solid solution with composition-dependent vacancies.
Study on the Regeneration of Mn2O3 Catalyst for Simultaneous Abatement of NOx and SOx
Authors: Sato Toshio , Ueno Akifumi , Todo Naoyuki , Kurita Minoru , Hagiwara Hiroyuki , Nishijima Akiko , Kiyozumi Yoshimichi
Published: July 2006

A technique to regenerate catalysts used for the simultaneous abatement of NOx and SOx in flue gases was investigated. Formation of sulfate ions on the metal which is an active component of the catalyst was proved to be a poison for the catalysis. The most effective means to remove the sulfate ions on the catalyst is to heat the used catalyst at 300 °C in NH3–water vapor.
A Thermodynamic Study on Hydrolytic Reactions of Lead(II) Ions in an Aqueous Solution and Dioxane–Water Mixtures. II. A Calorimetric Study
Authors: Ishiguro Shin-ichi , Ohtaki Hitoshi
Published: July 2006

The hydrolytic reactions of lead(II) ions were calorimetrically studied at 25 °C in an aqueous solution and dioxane-water mixtures (dioxane contents: 0.1 and 0.2 mole fractions, which correspond to 35.21 and 55.01 % w/w, respectively) both containing 3 mol dm−3 (Li)ClO4 as a constant ionic medium. A fully automatic on-line system was used for the calorimetric titrations. Values of enthalpies and entropies for the formation of the Pb3-(OH)33+, Pb4(OH)44+, Pb3(OH)42+ and Pb6(OH)84+ complexes in the aqueous solution, 0.1 and 0.2 mole fraction dioxane solutions were given. For the reaction qPb2++pH2O=Pbq(OH)p(2q−p)++pH+, the values of ΔHpq*/kJ mol−1 and TΔSpq*/kJ mol−1 were determined as follows: Pb3(OH)33+ 66.6, −20.7 (in aqueous solution); 72.1, −13.4 (in 0.1 mole fraction dioxane solution); 66.9, −17.7 (in 0.2 mole fraction dioxane solution); Pb4(OH)44+: 81.4, −29.5;84.1,−22.1;94.7,−14.7; Pb3(OH)42+: 61.6, −68.4;83.4,−41.0,99.8,−24.3; Pb6(OH)84+:242.8, 1.3, 243.2, 10.6; 236.7, 2.0. The solvent effects on ΔHpq* were discussed in terms of a function of the formal charge per metal ion of the complex, z′=(2q−p)⁄q. The thermodynamic parameters obtained for the Pb6(OH)84+ complex were better explained by assuming the reaction, 2Pb3(OH)42+=Pb6O(OH)64++H2O, than the reaction, 2Pb3-(OH)42+=Pb6(OH)84+, and thus the Pb6(OH)84+ complex formally written from the result of the potentiometric measurements will be described as Pb6O(OH)64+ which has previously been proposed by X-ray diffraction.
A Reexamination of the Robinson Annelation of 2-Methylcyclohexanone with 3-Penten-2-one and 4-Phenyl-3-buten-2-one
Authors: Kikuchi Mitsuko , Yoshikoshi Akira
Published: July 2006

The reported Robinson annelation of 2-methylcyclohexanone with 3-penten-2-one has been reexamined. In contrast to the previous result, it was found that the reaction product was not only obtained in a low yield, but also the solvent-depending stereoselectivity in the formation of cis-4,4a-dimethyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one (3a) and its trans isomer (3b) was considerably lower than that reported. As expected, regioisomers, 4β,8α-dimethyl-4,4aβ,5,6,7,8-hexahydronaphthalen-2(3H)-one and 4β,8β-dimethyl-4,4aα,5,6,7,8-hexahydronaphthalen-2(3H)-one, were also formed in the annelation. A similar tendency was observed in the reaction with 4-phenyl-3-penten-2-one. The annelation products, 3a, 3b, cis-4-phenyl-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2(3H)-one, and trans-4-phenyl-4a-methyl-4,4a,5,6,7,8-hexahydronaphthalen-2 (3H)-one, were also synthesized by an alternative route.
ortho-Disubstituted F-Benzenes. III. Preparation of (F-Benzo)heterocyclic Compounds from F-Benzoic Acid and F-Phenol, and the Reactions of Some Intermediary F-Benzoyl- and F-Phenoxy Compounds
Authors: Inukai Yoshinari , Oono Yoshitsugu , Sonoda Takaaki , Kobayashi Hiroshi
Published: July 2006

With the intention of achieving the selective ortho-substitution of F-benzoic acid and F-phenol via intramolecular nucleophilic cyclization, preparation of some requisite precursory F-benzoyl- and F-phenoxy compounds and their nucleophilic cyclization reactions were examined. 1,2-(F-Benz)isoxazol-3(2H)-one, 2-(p-tolyl)-1,2-(F-benz)isoxazol-3(2H)-one, 1,3-dimethyl(F-benzo)pyrimidine-2,4(1H,3H)-dione, and 1,4-(F-Benz)oxazin-3(2H)-one were obtained from the respective precursory F-benzohydroxamic acid, N-(p-tolyl)-N-hydroxy-F-benzamide, N,N′-dimethyl-N-(F-benzoyl)urea, and 2-(F-phenoxy)acetohydrazide. Attempted cyclizations of 2-(F-phenoxy)acetohydroxamic acid and (F-phenoxy) acetic acid were accompanied by simultaneous ring-opening and resulted in the formation of the identical product: (2-hydroxy-F-phenoxy)acetic acid. Transamidation of ethyl F-benzoate with hydroxylamine failed to give F-benzohydroxamic acid, which was then obtained by the catalytic debenzylation of N-benzyloxy-F-benzamide.
Reduction by a Model of NAD(P)H. 32. Stereoselective Reduction of Camphoroquinone by a Chiral NAD(P)H Model
Authors: Ohno Atsuyoshi , Goto Takehiko , Nakai Jun-ichi , Oka Shinzaburo
Published: July 2006

(+)-, (−)-, and racemic camphoroquinones (CQ) were reduced by each of four NAD(P)H-models such as N-(α-methylbenzyl)-1-propyl-2,4-dimethyl-1,4-dihydronicotinamide (Me2PNPH) in the presence of magnesium ion in acetonitrile with a view to elucidating the intermolecular arrangement in the transition state for asymmetric reduction. Partial rate factors for each attacking mode were calculated. Electronegative substituents in the substrate prefer to facing the carbamoyl group in Me2PNPH, which is the most important factor determining the stereochemical course of the reduction. 1-Methyl group in CQ has a tendency to interfere with the dihydropyridine moiety in Me2PNPH approaching the C2-carbonyl group in CQ. This interference is more important for the selectivity than the intrinsic exo/endo reactivity difference.
Reactions of Group V Metal Compounds with Sulfur Trioxide
Authors: Ando Fumio , Koketsu Jugo , Ishii Yoshio
Published: July 2006

Trialkylphosphines react with equimolar amounts of sulfur trioxide to form the 1:1 adducts R3P⊕–SO3\ominus. Trialkylarsines and -stibines undergo sulfur trioxide insertion reactions across the metal-carbon bond to give the trisulfonates of the metal M(OSO2R)3 (M=As, Sb). The reactions of trialkyl phosphites, with sulfur trioxide yield trialkyl phosphates, trialkyl thiophosphates, dialkyl alkylphosphonates, dialkyl sulfates, and polymers which contain phosphorus atoms. The reactions of trialkoxyarsines and -stibines result in the insertion of sulfur trioxide across the metal-oxygen bond to form the alkoxymetal alkylsulfates (RO)3−nM(OSO3R)n (M=As, Sb; n=1, 2, 3) depending on the stoichiometric ratios of the reagents used. Pyrolysis of the metal sulfates gives dialkyl sulfates and undistillable residues containing the metals.
Photochemistry of 9-[2-(N-Substituted Aminotnethyl)-1-naphthyl]phenanthrenes. Intramolecular Addition of Amines to Excited State of Phenanthrene in Conformationally Rigid System
Authors: Sugimoto Akira , Sumida Ryozo , Tamai Naoto , Inoue Hiroo , Otsuji Yoshio
Published: July 2006

Irradiation of benzene solutions of 9-[2-(N-substituted aminomethyl)-1-naphthyl]phenahthrenes (3a–d) gave pyrroline derivatives by the attack of the NH group on the C-9 carbon atom of the phenanthrene ring. The reactions were highly selective in regio- and stereochemical senses, and occurred through exciplexes formed by intramolecular interaction between the ammo group and the excited phenanthrene moiety in 3a–d. Mechanistic features of these photoreactions are discussed on the basis of chemical and photochemical properties of substrates and products.
Reactions of Ketone Hydrazones and β-Keto Enamines with Disulfur Dichloride. New Synthesis of Thioketones and 5H-1,2,3-Dithiazoles
Authors: Okazaki Renji , Inoue Kaoru , Inamoto Naoki
Published: July 2006

Ketone hydrazones react with disulfur dichloride in the presence of triethylamine to afford thioketones in good yields. The reaction mechanism involving N-thiosulfinylamine (R2C=N–N=S=S) and S-thioxothioketone (R2C=S=S) is proposed. The formation of t-butyl and di-1-adamantyl thioketones even at low temperatures has been interpreted as steric congestion alone being not enough to stabilize the corresponding S-thioxothioketones. The reaction of β-ketoenamines with disulfur dichloride gives 5H-1,2,3-dithiazoles via intramolecular cyclization of intermediary N-thiosulfinylamines.
Kinetics and Mechanism of Oxidation of Dimethyl Sulfoxide by Peroxomonosulfate
Authors: Pandurengan Thanthoni , Maruthamuthu Pichai
Published: July 2006

The kinetics of oxidation of dimethyl sulfoxide (DMSO) by peroxomonosulfate (PMS) was carried out in aqueous H2SO4 medium (0.1–0.5 M H+) and in buffered media, pH=4.6 and 7.0, at temperatures, 10 and 20 °C. The reaction obeys a total second order kinetics, first order each with respect to [PMS] and [DMSO]. The rate was found to be immeasurably fast at pH≥9 and T>20 °C. In strong acid medium, [H2SO4]=0.1–0.5 M, the reaction was found to follow an inverse first order dependence on [H+]. The rate law for the disappearance of PMS is found to be

Rate={ka+kb[H+]−1}[PMS][DMSO]

indicating both the acid-independent and inverse acid-dependent reactions occurring concurrently. Dimethyl sulfone was identified as the oxidation product and the reaction stoichiometry, [DMSO]:[PMS] was found to be 1:1. The kinetic and thermodynamic parameters evaluated strongly suggest the nucleophilic substitution mechanism characteristic of peroxides. A comparison is also made with the corresponding reactions of the similar peroxides, H2O2, S2O82−, P2O84−, and H2PO5−.
Partial Hydrogenation of Acetylenes on Modified Nickel Boride Catalysts
Authors: Nitta Yuriko , Imanaka Toshinobu , Teranishi Shiichiro
Published: July 2006

Ni–B catalysts modified with a small amount of copper(II) salt have a higher selectivity than palladium and modified Raney nickel catalysts for partial hydrogenation of phenylacetylene, 1-heptyne, 1-ethynylcyclohexene, and propargyl alcohol.
The Molecular Conformation of 6,14-Di-O-acetyl-3-O-(2-chlorobenzoyl)-grayanotoxin II as Revealed by X-Ray Methods
Authors: Furusaki Akio , Hamanaka Nobuyuki , Matsumoto Takeshi
Published: July 2006

An X-ray crystal analysis has revealed that the six-membered C-ring in the title compound takes a boat conformation, in contrast with that in grayanotoxin II itself.
Equilibrium Dissociation Pressure of Hydrogen in Molten LiCl–LiH Mixtures
Authors: Ichikawa Kazuhiko , Kawamura Kazutaka
Published: July 2006

Pressure-composition-temperature data were collected for the LiCl-LiH system in the respective ranges 0.1–10 mmHg, 4.5–22.3 mol% LiH, and 550–700 °C by measuring equilibrium hydrogen pressure in a Sieverts’ apparatus. The square root of hydrogen pressure vs. composition isotherm follows Sieverts’ relation for compositions below 10 mol% LiH.
Preparation and Circular Dichroism Spectrum of a (Triazacyclononane)(tribenzo[b,f,j] [1,5,9]triazacyclododecene)cobalt(III) Complex
Authors: Fujinami Shuhei , Hosokawa Takao , Shibata Muraji
Published: July 2006

A new [Co(tacn)(tri)]3+ complex has been prepared and optically resolved (TACN represents 1,4,7-triazacyclononane, and TRI, tribenzo[b,f,j][1,5,9]triazacyclo dodecene). From the CD spectral similarity of (+)500CD-[Co(tacn)(tri)]3+ with (+)546[Co(tri)2]3+, it has been concluded that the metal-centered optical activity of the two tri complexes is derived from a chiral arrangement of (benzene ring)–C=N– moieties.
MINDO/3 Calculations of Kinetic Isotope Effects in Heterolysis of Neopentyl Alcohol
Authors: Ando Takashi , Yamataka Hiroshi , Yabushita Satoshi , Yamaguchi Kizashi , Fueno Takayuki
Published: July 2006

Geometrical optimization of the protonated neopentyl alcohol and the transition state of its heterolysis was carried out using the MINDO/3 SCF-MO method. A cyclic structure was predicted for the transition state. Agreement between the calculated and experimental values for the carbon-14 kinetic isotope effects was excellent.
Preparation of (R)-N,N-Dimethyl-1-[2-(diphenylphosphino)ferrocenyl]-2-propanamines and Asymmetric Grignard Cross-coupling Catalyzed by Nickel Complexes with the Phosphine Ligands
Authors: Hayashi Tamio , Konishi Mitsuo , Hioki Takeshi , Kumada Makoto , Ratajczak Aleksander , Niedbala Halina
Published: July 2006

A pair of diastereoisomeric phosphines, (R)-N,N-dimethyl-1-[2-(diphenylphosphino) ferrocenyl]-2-propanamines, have been prepared and used as ligands for nickel-catalyzed asymmetric cross-coupling of 1-phenylethylmagnesium chloride with vinyl bromide to give 3-phenyl-1-butene of 14–15% enantiomeric excess.
An NMR Study on the Association Stabilities of Thiaheterohelicenes against 7,7,8,8-Tetracyanoquinodimethan. Effect of the Staggered Configuration of Helicene
Authors: Tanaka Hisao , Nakagawa Hiroko , Yamada Koh-ichi , Kawazura Hiroshi
Published: July 2006

In order to evaluate the influence of the staggered configuration of helicene on complex formation, a 1H NMR technique was applied to the complexing equilibria of thiaheterohelicene homologs with 7,7,8,8-tetracyanoquinodimethan (TCNQ). Formation constants of the complexes showed irregular changes in the case of [5] and [7]thiaheterohelicenes in which the staggerings occur. This irregularity could be interpreted on the basis of the observed abnormal decrease of the bonding entropy. The reduced bonding entropy was understood in terms of the incomplete quenching of internal freedom, which was expected from the peculiar orientation of the staggered thiaheterohelicene towards planar TCNQ, in the charge-transfer complex.
A Study of the Electronic States of Iridium(III) Complexes Containing 1,10-Phenanthroline Ligands. The Contribution of a dd Excited State to the Lowest Triplet State
Authors: Ohashi Yukako
Published: July 2006

To investigate the solvent dependence of the dd contribution to the lowest excited state of cis-[IrCl2L2]Cl (L=1,10-phenanthroline (phen) and 5,6-dimethyl-1,10-phenanthroline (5,6-Mephen)), the triplet-triplet absorption spectra (15000–25000 cm−1) were measured in N,N-dimethylformamide (DMF)–water mixed solvents. From a smaller solvent-dependence of the absorption intensity for [IrCl2(5,6-Mephen)2]Cl than for [IrCl2(phen)2]Cl, the lowest triplet state of the former is considered to have a ππ* character in 95% v/v DMF–water and 45% v/v DMF–water. However, in pure water a considerable decrease in the triplet-triplet absorbance was observed. Because the molar extinction coefficient of the triplet-triplet absorption of the dd-dd type is 10−2 times smaller than that of the ππ*-ππ* type, the observed decrease in the absorbance is elucidated by the increase in the contribution of the dd state to the lowest triplet state. Using ethanol–methanol (4 : 1, v/v) as a solvent, it was confirmed that the triplet-triplet absorption spectrum shows no change when the solutions are degassed and the temperature is lowered (77 K).
The Cadmium-photosensitized Reaction of Saturated Tertiary Amines
Authors: Yamamoto Shunzo , Yasunobu Masae , Nishimura Norio
Published: July 2006

Rate constants for the quenching of the cadmium resonance line at 326.1 nm by triethylamine (TEA), N-ethylpiperidine (NEP), and 1-azabicyclo[2.2.2]octane (ABCO) were obtained. Relative rate constants for the formation of an exciplex between an excited cadmium atom and these amines and quantum yields for the emission from the exciplex were also obtained. Contrary to the case of primary amines, in which the electron-donating ability of the nitrogen atom is operative, the exciplex formation in the present case is mainly governed by the magnitude of the steric effect of ethyl groups on the interaction between the nitrogen atom and an excited cadmium atom. Gaseous products were hydrogen, methane, ethane (and/or ethylene), and butane. The quantum yields of these products indicate that the primary photochemical products are methyl and ethyl radicals for TEA and NEP. The amount of products for ABCO was considerably smaller than those for other amines.
Reactions of Aromatic Radical Anions with Benzhydryl Chloride Studied by Pulse Radiolysis
Authors: Takamuku Setsuo , Kigawa Hitoshi , Toki Susumu , Tsumori Kunihiko , Sakurai Hiroshi
Published: July 2006

Reactions of the aromatic radical anions with benzhydryl chloride have been investigated by pulse radiolysis. The second-order rate constants were determined for the reactions of benzhydryl chloride with various aromatic radical anions. On the basis of the linear relationship between the free energy and the activation energy, an irreversible electron transfer with an early transition state was elucidated.
Partition of Carboxylic Acids between Benzene and Aqueous Solution as Considered from the Regular Solution Theory
Authors: Fujii Yukio , Tanaka Motoharu
Published: July 2006

The partition of carboxylic acids between benzene and 0.1 mol dm−3(H,Na)ClO4 aqueous solution has been studied at 25 °C. Carboxylic acids used include acetic, propanoic, butanoic, pentanoic, hexanoic, and decanoic acids. The hydration of monomeric acids in benzene being taken into account, the hydration-corrected partition constant has been calculated. The effect of the chain length on the partition is accounted for with the aid of the newly estimated solubility parameters and empirical binary coefficients. Applicability of the empirical solubility parameter of water (35.89 J1⁄2 cm−3⁄2) has also been discussed.
Spectrophotometric Determination of Formation Constants and Estimation of Molar Absorption Spectra of Individual Components in Chemical Equilibria. Infrared Study of Intermolecular Hydrogen Bonding of 2-Aminopyridine
Authors: Sugeta Hiromu
Published: July 2006

A general method is developed for evaluating formation constants and molar absorption coefficients of constituent species from spectrophotometric data for a multicomponent equilibrium system. The method is applied to analyzing infrared spectra for the intermolecular hydrogen bond system of 2-aminopyridine in carbon tetrachloride solution. 2-Aminopyridine assumes a cyclic dimer structure by dint of an intermolecular hydrogen bonding and the formation constant for the dimerization is 1.4±0.1 mol−1 dm3 at 30 °C.
Electrochemical Properties of Ferrocenophanes. I. Voltammetric Studies on the Oxidation of Mono-, Di-, and Tri-bridged Ferrocenophanes in Acetonitrile
Authors: Ogata Tateaki , Oikawa Kazuo , Fujisawa Tadashi , Motoyama Shunsuke , Izumi Taeko , Kasahara Akira , Tanaka Nobuyuki
Published: July 2006

Electrode reactions of mono-, di- and tri-bridged ferrocenophanes ([3]Fcp, [4]Fcp, [3][3]Fcp, [4][3]Fcp, [4][4]Fcp, [3][3][3]Fcp, [4][4][3]Fcp and [4][4][4]Fcp) in acetonitrile were investigated by direct current polarography, pulse polarography, and cyclic voltammetry. The oxidation of these compounds proceeds reversibly as a one-electron process. The linear relationship between the half-wave potential and the number of methylene groups was obtained for ferrocene and ferrocenophanes other than [3][3]Fcp and [3][3][3]Fcp. The Taft substituent constants of trimethylene and tetramethylene groups were estimated.
Reactions of Manganese(III) Schiff Base Complexes with Superoxide Ion in Dimethyl Sulfoxide
Authors: Matsushita Takayuki , Shono Toshiyuki
Published: July 2006

The reactions of the chloromanganese(III) complexes of the Schiff bases derived from salicylaldehydes or β-diketones and diamines or monoamines with superoxide ion, O2−, in dimethyl sulfoxide were investigated. The complexes were found to react to give either the oxygenated Mn Schiff base complexes or the reduced Mn(II) Schiff base complexes. The difference in the reactivity toward O2− was correlated to the polarographic half-wave potentials corresponding to the reduction of Mn(III) to Mn(II) of the complexes. Some oxygenated complexes were isolated and characterized.
Binding of Sodium Decyl Sulfate to a Cationic Polymer
Authors: Shirahama Keishiro , Yuasa Hidefumi , Sugimoto Shinji
Published: July 2006

Interaction between sodium decyl sulfate and a cationic copolymer of dimethyldiallylammoniurn chloride and sulfur dioxide was studied by a potentiometric method utilizing a surfactant-selective electrode. Binding occurs suddenly and is completed in a very narrow range of equilibrium concentration, indicating the strongly cooperative nature of the binding process. The characteristic concentration at which binding starts is about two orders of magnitude smaller than the critical micelle concentration. The cooperativeness parameters as estimated by a nearest neighbor interaction model remains almost constant on increasing sodium chloride concentration, affinity for an isolated binding site decreasing.
The Formation of Molybdenum Disulfide by the Reaction between Molybdenum Trioxde and Sulfur Dioxide in the Presence of Carbon
Authors: Yajima Akimasa , Matsuzaki Ryoko , Eguchi Motonori , Saeki Yuzo
Published: July 2006

The reaction products obtained by heating a mixture of MoO3 and carbon in a SO2 stream at various temperatures were examined. The possible reactions during the above process were also studied. Further, thermodynamical consideration was made of the formation of MoS2. When a mixture of MoO3 and carbon was heated in a SO2 stream, MoO2 was formed above 400 °C. At 500–550 °C, the formation of a small amount of Mo4O11was also observed. Above 700 °C, the formation of MoS2 in addition to MoO2 was observed, and MoS2 alone was obtained at 1000 °C. Sulfur was obtained outside the heating zone throughout the temperature range in this experiment. The process of the formation of MoS2 by the reaction between MoO3 and SO2 in the presence of carbon can be represented as follows: The reaction between carbon and SO2 occurs at first to form sulfur. Above ca. 400 °C, the reductions of MoO3 with carbon and with sulfur occur to form MoO2. Above ca. 700 °C, MoS2 is formed by the reaction between MoO2 and sulfur, which are formed by the above reactions.
Selective Extraction Spectrophotometric Determination of Iron by Utilizing the Peculiar Absorption of Iron(II)–2-(2-Thiazolylazo)-5-dimethylaminophenol Complex
Authors: Ueda Kazumasa , Kiyota Yasushi , Yamamoto Yoshikazu
Published: July 2006

Thiazolylazo compounds react with iron(II) to form brownish complexes, which show a characteristic absorption in near-infrared region. These compounds possess the hydroxyl group in the o-position next to the azo group. Among them, iron(II)-2-(2-thiazolylazo)-5-dimethylaminophenol complex has the absorption maximum at 760 nm in chloroform; the optimum pH for iron extraction lies between 8.2–10.0. Beer’s law holds up to 2.0 μg cm−3 of iron and the molar absorption coefficient is 2.70×104 dm3 mol−1 cm1. The composition and the extraction constant of the complex are estimated to be Fe: TAM=1 : 2 and logKex=−4.20±0.04, respectively. Since the present method utilizes the specific absorption of the iron(II)-TAM complex, the presence of many ions is tolerable, especially of 3d type metals. The method was applied to the determination of traces of iron dissolved in river and sea waters with satisfactory results.
Electronic Structures and Spectra of the Enol Form of Some β-Diketones
Authors: Morita Hiroshi , Nakanishi Hiroshi
Published: July 2006

Near and vacuum UV absorption spectra have been measured with benzoylacetone (BA), dibenzoylmethane (DBM), and 3-phenyl-2,4-pentanedione (PPD) in heptane, in acetonitrile, and in ethanol at room temperature. Theoretical analysis of the spectra with the aid of the composite molecule method clearly shows that the π-electron interaction between the enol ring and the benzene ring is rather strong in BA and DBM, but is weak in PPD. The charge-transfer (CT) bands from the benzene ring to the enol ring are observed at 44000 cm−1 in BA, at 40000 and 44000 cm−1 in DBM, and at 41500 and 43800 cm−1 in PPD. The electronic structure of the enol form of malonaldehyde has been elucidated by a modified CNDO-CI method; the result indicates the first and second σ-σ* excited states predicted at 8.76 and 9.35 eV being the CT band pertinent to the intramolecular hydrogen-bonding.
Bovine Serum Albumin Coordinated Iron-Sulfur Cluster as a Hydrogenase Model
Authors: Okura Ichiro , Nakamura Satoshi , Kobayashi Masatoshi
Published: July 2006

The bovine serum albumin coordinated Fe4S4-cluster, which had hydrogenase activity, was synthesized. Its physical and chemical characteristics were then compared with those of natural hydrogenase. Though the affinities of hydrogenase and the albumin-coordinated Fe4S4-cluster for the substrate, methyl viologen, were similar, the hydrogenase activity for hydrogen evolution was 105 times greater than the cluster. Two types of Fe4S4-clusters, coordinated by the fragments of the cleaved albumin obtained by treatment with cyanogen bromide, were synthesized, and their hydrogenase activities were compared. The activity with the iron-sulfur cluster incorporated in the fragment with MW 40000 was much higher than that of the one incorporated in the fragment with MW 20000. The amino acid arrangement to form the active site was discussed on the analogy of the other iron-sulfur proteins.
Cyclic Voltammetry of Aromatic Amine N-Oxides in Nonaqueous Solvents and the Stability of the Free Radicals Produced
Authors: Miyazaki Hiroshi , Matsuhisa Yoshio , Kubota Tanekazu
Published: July 2006

Cyclic voltammograms of aromatic amine N-oxides were recorded in nonaqueous solvents at various sweep rates less than 10 V/s. The measurement was carried out for both cathodic and anodic sweeps, and the sweep rate for obtaining a good cyclic voltammogram was correlated with the wave height of the a.c. polarogram in the reduction and oxidation processes, respectively. A good correlation was found between the sweep rate and the wave height in both the reduction and oxidation processes. This confirmed that the two values serve as good measures of the stability of the anion or cation free radical produced by the electrode reaction of the aromatic amine N-oxides. The data were also examined by comparison with results from an electron spin resonance study. Finally, the temperature effect on the cyclic voltammogram of pyridine N-oxide was investigated in detail.
The Action of Boron Trifiuoride on Aromatic Nitrile Oxides
Authors: Shiraishi Shinsaku , Shigemoto Tadashi , Miyahara Masatoshi , Ogawa Shojiro
Published: July 2006

The action of boron trifluoride etherate on stable aromatic nitrile oxides effected the isomerization of nitrile oxides into isocyanates competitively with their dimerization to 1,4,2,5-dioxadiazines and/or (1,2,4-oxadiazol-4-io)oxytrifluoroborates. Quenching the reaction with methanol at an earlier stage of the reaction gave methyl benzohydroximate. The reacion was interpreted in terms of the initial coordination of BF3 with the nitrile-oxide-oxygen atom.
Solid Phase Synthesis of Crystalline Protected Penta-l-tryptophan Methyl Esters
Authors: Ueki Masaaki , Ikeda Shigeru , Handa Takashi
Published: July 2006

Solid phase syntheses of protected tryptophan homo-oligomers were accomplished by utilizing dimethylphosphinothioyl(Mpt) group as an Nα-amino protecting group which was removed by treatment with triphenylphosphine dihydrochloride. By measurements of the ultraviolet and fluorescence spectra it was ascertained that no modification on the tryptophan indole ring had occurred during these syntheses.
The Photoelectrochemical Reaction of the Chlorophyll-Irisquinone Electrode
Authors: Takahashi Fujio , Seki Katsura , Kaneko Ryohei , Sato Kenji , Kusumoto Yasushi
Published: July 2006

The role of irisquinone (IQ) in the chlorophyll-IQ electrode was studied by measuring the photoresponse under illumination and the photocurrent at the controlled potential. It was concluded that the hydrophobic property of IQ was necessary for the photoresponse to occur at the chlorophyll electrode, and that the photoexcited chlorophyll was likely to eject electrons to a counter electrode via an outer circuit and to pull electrons from the reduced IQ, which had been produced by the oxidation of a reducing compound in the electrolyte on the chlorophyll-IQ electrode.
Stereochemical Behavior of 1-Methoxycyclopropyl Radical in Hunsdiecker Reaction
Authors: Ando Teiichi , Ishihara Takashi , Yamashita Akira , Matsumoto Masahiro
Published: July 2006

The Hunsdiecker reaction of Ag (E)- and (Z)-2,2-dichloro-1-methoxy-3-methylcyclopropanecarboxylates with bromine in CCl4 at 0 and 77 °C occurs with substantial inversion of configuration, suggesting that the 1-methoxycyclopropyl radical is configurationally less stable than the 1-fluorocyclopropyl or the 1-methoxyvinyl radical.
Electron Spin Resonance Study on the Difference of Structure in Diastereomeric Nitroxyl Radicals
Authors: Kotake Yashige , Kuwata Keiji
Published: July 2006

Electron spin resonance spectra of nitroxyl radicals bearing two asymmetric carbons were observed. The radicals were produced by the abstraction of a hydrogen atom from ethers and amines by photoexcited benzophenone, followed by spin trapping with phenyl-N-t-butylnitrone. The spectra showed the presence of two radical species assignable to diastereomers in most cases. The presence of isomers was seen more clearly in ESR spectra of radicals produced from ethers than those from amines. The origin of the different ESR parameters of the isomer was discussed in detail and it was concluded that the functional group on β-carbon acts as a group of proximity to nitroxyl function. The difference of the electronegativity of the atom in each functional group causes the difference of the extent of the separation of isomers. The effects of proximity groups on observed ESR parameters are concluded to be the same as the solvent effect.
Redox Reaction of the Central Metal Ions Coordinated to Tetra(p-sulfophenyl)porphine(TPPS). I. Photoreduction of Co(III)TPPS by Methanol and 2-Propanol
Authors: Hatano Keiichiro , Usui Kiyoko , Ishida Yoshitaka
Published: July 2006

Trivalent cobalt ion coordinated to 5,10,15,20-tetra(p-sulfophenyl)porphine (TPPS) in deaerated solution was reduced to the divalent ion on illumination of light with simultaneous oxidation of alcohols. The resulting divalent ion in the porphyrin was reoxidized by admission of dioxygen or air into the solution. It was found that the metalloporphyrin played a photocatalytic role in the autoxidation of alcohols. The kinetic study on the photoreduction revealed that the reduction rate of Co(III) followed the pseudo-first-order rate expression at 20 °C and pH 6.5 to 11.5 in the presence of excess methanol or 2-propanol. The observed rate constants were dependent on [alcohol] and/or pH. Possible mechanism for the photoreduction of Co(III)TPPS in the aqueous solution was discussed in terms of preequilibrium reactions of the axial ligation of substrates to the metalloporphyrin.
New Application of Crown Ether. V. The Effect of Crown Ethers on the Acid–Base Interaction between 2,4,4′,6-Tetranitrodiphenylamine and Primary Amines in Benzene
Authors: Wada Fumio , Wada Yoshiko , Kikukawa Kiyoshi , Matsuda Tsutomu
Published: July 2006

The effect of crown ethers on the acid-base interaction of 2,4,4′,6-tetranitrodiphenylamine (HA, λmax 380 nm, pKa=8.88 in water) with primary amines (RNH2) in benzene was investigated spectrophotometrically. Crown ethers assisted strongly the formation of association complexes, R\overset+NH3·crown ether·A−, which existed as a single chemical species (λmax 478 nm) assignable to “crown ether-separated ion pair.” The effect of the steric factors of various primary amines on the equilibrium to form the association complex was discussed on the basis of the equilibrium constants and thermodynamic parameters of the systems involving 18-crown-6 and benzo-18-crown-6.
Photoinduced Intramolecular Aromatic Nucleophilic Substitution (the Photo-Smiles Rearrangement) in Amino Ethers
Authors: Mutai Kiyoshi , Kobayashi Keiji
Published: July 2006

Intramolecular rearrangement was induced by light as well as base in a homologous series of 1-(p-nitrophenoxy)-ω-anilinoalkanes, p-O2NC6H4O(CH2)nNHPh(n=2–5), yielding N-(p-nitrophenyl)-ω-anilino-1-alkanols, p-O2NC6H4N(Ph)(CH2)nOH. The reaction rate in acetonitrile showed abnormal order, n=4>5>3>2, which was reversed by the addition of triethylamine. The mechanism of this photorearrangement through a radical ion pair and a spiro type Meisenheimer complex was proposed. The anomaly in the reaction rate order was discussed on the basis of this mechanism.
Hydration of Aza-aromatic Aldehydes. II. Solvent Effect on the Equilibrium Constants of the Hydration
Authors: Abe Kazuhisa , Endo Hiroko , Hirota Minoru
Published: July 2006

The equilibrium constants for the hydration reaction of 4-pyridinecarbaldehyde were determined in several solvents by 1H-NMR spectroscopic measurements. The hydration reactions were sensitive to the nature of the solvents. In strong donor solvents such as hexamethylphosphoric triamide, pyridine, and dimethyl sulfoxide, formation of the hydrate is far more favorable than in water or other poor donor solvents. Thus the stabilization of the product by hydrogen bond formation is assumed to favor the reaction. Polarity of the solvent alone does not explain the solvent effect, even if it is supposed to affect the equilibria secondarily.
Effect of Cationic Micelles on the pKa Values of Disulfones
Authors: Yano Yumihiko , Kawada Shuji , Tagaki Waichiro
Published: July 2006

The acid dissociation constants of carbon acids activated by two sulfonyl groups were determined spectrophotometrically in aqueous solution with and without GTAB micelles. The results indicate that a cationic micelle causes larger pKa decrease for more hydrophobic disulfones. Hydrophobic properties of cyclic and acyclic disulfones are discussed.
The Determination of the “Flat-band” Potential of Nitrogen-stabilized n-TiO2 Photoanode
Authors: Hirai Taketsugu , Tari Isao , Ohzuku Tsutomu
Published: July 2006

The differential capacitance (C) and the photocurrent onset voltage (Ep) of nitrogen-stabilized n-TiO2 semiconductor electrodes were measured in buffered Na3PO4 solutions. The C−2  vs.  E plots did not show the Mott-Schottky (MS) behavior. In order to explain the nonlinearity in MS plots, the distribution in donor density (Nd) at the solid side and the contribution of the electrical double layer at the solution side to the total capacitance were considered. The characterized flat-band potential (Efb) and the zero-charge potential (Ezc) were defined from the derived equations. The roles of the defined Efb and Ezc in the photocurrent onset voltage (Ep) were also considered, and the reason why Ep differed from Efb was explained using the “Gate” model.
Shock Tube Studies of the Acetylene and Ethylene Pyrolysis by UV Absorption
Authors: Koike Tohru , Morinaga Kihei
Published: July 2006

Absorption measurements at 216 and 230 nm of shock heated C2H2, C2H2+H2, and C2H4 diluted in Ar were made over the temperature range 1800 K to 2600 K at half of atmospheric pressure. Absorptivities were evaluated for C4H2, which is the main product of C2H2 pyrolysis, as well as for C2H2 and C2H4. The relative value of C4H2 absorption was confirmed to decrease with the presence of H2 in accordance with a computer modeling result using a 25-reaction mechanism. The time profile of C4H2 absorption could be modeled well with k=1012.4 cm3 mol−1 s−1 for the reaction H2+C2H=C2H2+H.
Adsorption of d-, l-, and Dl-Phenylalanines at the Mercury–Aqueous Solution Interface
Authors: Kakiuchi Takashi , Senda Mitsugi
Published: July 2006

The adsorption of d-, l-, and Dl-phenylalanines at the mercury-aqueous sodium fluoride solution interface has been studied by measuring differential capacities, potentials of zero charge, pzc, and surface tensions at the pzc. The racemate of phenylalanine showed higher surface activity than the enantiomers. This difference has been interpreted in terms of the intermolecular interactions, orientation and re-orientation of adsorbed molecules at the interface.
Interaction between Aromatics and Zinc Chloride. III. The Dissociation of Triphenylmethane and 9,10-Dihydroanthracene into Ions
Authors: Morita Mikio , Hirosawa Kunio , Sato Toshio , Ouchi Koji
Published: July 2006

Triphenylmethane and 9,10-dihydroanthracene were found to produce colored complexes when placed in contact with molten zinc chloride or with solid zinc chloride pulverized or supported on porous Vycor glass. The triphenylmethane complex gave the same electronic absorption spectrum as that of the triphenylmethyl cation generated by contact with silica-alumina and BF3 on silica. The 9,10-dihydroanthracene complex exhibited the same electronic absorption band as that of the 9-anthracenium ion produced by the reaction of anthracene with concd H2SO4. The reaction of the triphenylmethane complex with deuterium gas provided HD gas and (C6H5)3CD. Similarly, the 9,10-dihydroanthracene complex and deuterium gas produced HD gas and 9,10-dihydroanthracene-9-d. Furthermore, their colored complexes on the supported zinc chloride gave a very weak IR absorption band at about 1720 cm−1, which is interpreted as corresponding to the formation of a Zn–H bond. These observations led us to conclude that triphenylmethane and 9,10-dihydroanthracene dissociate into ions . upon contact with zinc chloride:

(C6H5)3CH+nZnCl2 \ightleftarrows (C6H5)3C+(ZnCl2)n−H

(Remark: Graphics omitted.)
The Optical Absorption Spectra of Ferrocene and Biferrocene Anions Produced in the γ-Ray Irradiation by the Matrix-protection Method
Authors: Ikuta Shigeru , Kira Akira , Imamura Masashi , Motoyama Izumi , Sano Hirotoshi
Published: July 2006

The absorption spectra of the transient species produced through the one-electron reduction of ferrocene and biferrocene were determined by applying a radiation-chemical method in frozen glass matrices. The spectral shapes were assigned to ferrocene- and biferrocene-anionic species on the basis of the experimental results. In the biferrocene anion, the “intervalence transfer” band was observed at about 2050 nm.
Preparation of an Ideal Thin Mercury Film Electrode and Its Electrochemical Property
Authors: Yoshida Zenko
Published: July 2006

In order to get an ideal thin mercury film electrode, the structure of mercury film electrodeposited on foreign metals was investigated with the aid of the thermal-evaporation behavior of mercury and correlated to the electrode properties of the mercury-deposited surfaces. A mercury layer deposited on gold, copper, nickel, or platinum consists of stable mercury compounds with the base metal at their interface and a uniform metallic mercury layer on them. The hydrogen(H)-overpotential at the mercury-coated surface increases with the increase in the amount of mercury deposited. Mercury on molybdenum or stainless steel forms island-like metallic mercury droplets by electrodeposition. The H-overpotential at the surface is identical with that at molybdenum or stainless steel without mercury. Mercury deposited on lead or zinc easily forms a stable amalgam with the base metal, and no metallic mercury is present. The H-overpotential at the surface is slightly less than that at a base metal without mercury. A nickel-based thin mercury film electrode is recommended for such electroanalytical uses as anodic stripping voltammetry.
Metal-semiconductor Transition with Anomalous Thermal Hysteresis Observed in Hexagonal (Ni1−xFex)1−yS, (0≤x≤0.30, 0≤y≤0.035)
Authors: Ohtani Tsukio , Kosuge Koji , Kachi Sukeji
Published: July 2006

The phase relation of (Ni1−xFex)1−yS system was determined by the X-ray powder diffraction method. Fe1−yS can be dissolved in Ni1−yS in ca. 30 at.%. Transition temperature (Tt) was measured mainly by the DSC method. Tt increases with increase in Fe contents. Tt in the forward direction, however, shows a significant increase as high as 50 degrees, when specimens are aged at a temperature below Tt. The reverse transformation is not affected by thermal hystory at all. This is explained by the relaxation process in which the strain energy stored in the low temperature phase is relieved by aging.
Studies on the Uptake of Some Complex Cations of Copper by Molecular Sieves 4A and 5A
Authors: Thantry S S , Iyer K Veeramoni , Ramanathan P S
Published: July 2006

Studies on the uptake of Cu2+ and a few of its complex cations (i.e., [Cu(NH3)4]2+, [Cu(en)]2+, [Cu(en)2]2+, [Cu(pn)]2+, [Cu(pn)2]2+, and [Cu(tea)]2+, where en, pn, and tea represent ethylenediamine, propylenediamine, and triethanolamine respectively) by molecular sieves 4A and 5A were undertaken using batch equilibration procedure. [Cu(pn)]2+, [Cu(en)2]2+, [Cu(pn)2]2+, and [Cu(tea)]2+ showed very little affinity for the zeolite phases, while the uptake of Cu2+ and [Cu(en)]2+ was comparatively higher. [Cu(NH3)4]2+ occupied a position in between these two sets. During the equilibration of [Cu(en)]2+ and [Cu(pn)]2+ some side reactions could be observed leading to the conclusion that the 1:1 complex species underwent disproportionation, generating Cu2+ and an equivalent amount of [Cu(en)2]2+ or [Cu(pn)2]2+. These conclusions drawn from the batch equilibration studies were confirmed by appropriate column experiments.
Exchange Kinetics of Rubidium and Caesium Ions on Pyridinium Tungstoarsenate Exchanger
Authors: Jain Ajay K , Singh Raj P , Agrawal Sushma
Published: July 2006

The Kinetics of exchange of Rb+ and Cs+ has been investigated on pyridinium tungstoarsenate ion exchanger using limited bath technique. The exchange rate was studied as a function of concentration, temperature and particle size of exchanger to determine the slowest step. It was found that Rb+ exchange is particle diffusion controlled whereas Cs+ exchange shows dual behaviour at low concentration level. However, at higher concentrations, particle diffusion controls Cs+ exchange but the rate is concentration dependent. This anomalous behaviour has been explained by assuming that Cs+ exchange approaches closely to a chemical reaction. Thermodynamic parameters of exchange such as effective diffusion coefficient (D), activation energy (Ea) and entropy of activation (ΔS*) were calculated. The D and Ea values were found in the same order as that of ionic size, ΔS* value being positive for Cs+ exchange and negative for Rb+ exchange. A negative ΔS* value is usual but a positive value for Cs+ exchange might be due to dehydration of the cation while passing through the channels of the exchanger. This explanation is in line with that of interaction energy for the exchange of Cs+ on pyridinium tungstoarsenate.
Chemistry at Hydrocarbon–Water Phase Boundaries. Biphase Hydrolysis of Organic Halides
Authors: Ohtani Noritaka , Besse Jacques J , Regen Steven L
Published: July 2006

The kinetics of the biphase hydrolysis of 1-bromoadamantane and 1-phenylethyl chloride in toluene–water and decane–water systems have been investigated. Evidence has been obtained for the first examples of ratelimiting SN1 reactions occurring at a hydrocarbon–water phase boundary, based on (1) the influence of temperature, mild stirring, interfacial area, reaction volume, and pH on the observed first-order rate constants, (2) comparison of absolute rates and activation energies with analogous homogeneous hydrolysis reactions, (3) the temperature dependence of the initial rate of diffusion of tritiated 1-methoxyadamantane from toluene into water, and (4) the initial rate of diffusion of 3H2O into toluene.
The Crystal Structure of Bis(acetylacetonato)platinum(II) Benzene Solvate
Authors: Katoh Mitsunori , Miki Kunio , Kai Yasushi , Tanaka Nobuo , Kasai Nobutami
Published: July 2006

The crystal structure of bis(acetylacetonato)platinum(II) benzene solvate has been determined by means of X-ray diffraction. The geometry around the platinum atom is square-planar. Acetylacetonato ligands are bonded to the Pt atom by the O,O′-chelation, the Pt–O bond lengths being 2.008 (15) and 1.979 (14) Å.