bluuebunny/crossref_metadata_2025 huggingface dataset:
Reactions of 2-Aryl-2H-cycloheptathiazoles with Dimethyl Acetylenedicarboxylate
Authors: Abe Noritaka , Kondo Satoshi , Morita Koichi
Published: July 2006

Reaction of 2-aryl-2H-cycloheptathiazoles with dimethyl acetylenedicarboxylate gave dimethyl 2-aryl-3H-1-thia-2a-azacyclopent[cd]azulene-3,4-dicarboxylate, tetramethyl 6-phenyl-2,3,4,5-pyridinetetracarboxylate, and tetramethyl 5-[(thioaroyl)iminomethyl]-1,2,3,4-naphthalenetetracarboxylate.
Cobaltocene-Catalyzed Reaction of Carbon Dioxide with Propargyl Alcohols
Authors: Inoue Yoshio , Ishikawa Jiro , Taniguchi Masaaki , Hashimoto Harukichi
Published: July 2006

The reaction of carbon dioxide with α-ethynyl tertiary alcohols has been catalyzed by cobaltocene to give α-methylene cyclic carbonates in good yields. α-Ethynyl primary or secondary alcohols give noncyclic alkyl carbonates in fair yields.
Syntheses and Biological Activities of Substance P Analogs Containing l- and d-Homoglutamine and l- and d-Pyrohomoglutamic Acid at Position 5 and 6
Authors: Hashimoto Tadashi , Uchida Yoshiki , Nishijima Miwako , Sakura Naoki , Hirose Kyoko
Published: July 2006

Six substance P (SP) analogs substituted by l- and d-homoglutamine and l- and l-pyrohomoglutamic acid (6-oxo-2-piperidinecarboxylic acid) at position 5 and 6 were synthesized by standard solid phase method. The contractile activities of the analogs were compared with that of SP on isolated guinea-pig ileum and trachea.
Magnetic Properties of Some Molybdenum(V) Dimeric Coordination Compounds with Terminal Oxo-Ligands and Di-μ-, Di-μ-sulfido-or μ-Oxo-μ-sulfido- Bridges
Authors: Kobayashi Hanako , Shibahara Takashi , Uryû Norikiyo
Published: July 2006

Magnetic susceptibilities and electron spin resonances of Mo(V) dimers, Cs2[Mo2O2S2(ox)2(H2O)2]·2H2O, Ba[Mo2O4(ox)2(H2O)2]·3H2O, (pyH)4[Mo2O2S2(NCS)6], (pyH)4[Mo2O4(NCS)6]·H2O and (pyH)4[Mo2O3S(NCS)6] were observed at temperatures from 2 K to room temperature. The paramagnetic part of the magnetic susceptibilities of these compounds was small and approached zero with decreasing temperature. Under an applied magnetic field strength of 40 kOe, the susceptibilities had temperature independent regions but the spin susceptibilities derived from the electron spin resonances, observed at a magnetic flux density of about 3000 G, showed temperature dependences like antiferromagnetic dimers. This discrepancy was explained by a quasi alternating linear chain antiferromagnetic model. The corrections of the diamagnetic susceptibilities are discussed.
1H and 19F NMR Spectra of Some Fluorocyclobutane Derivatives
Authors: Takahashi Kensuke , Kimoto Hiroshi , Muramatsu Hiroshige
Published: July 2006

1H and 19F NMR spectra were observed at 60.00 and 56.46 MHz, respectively, for ten 1,1,2,2-tetrahalo-1, 2,2a,7a-tetrahydro-7H-cyclobut[a]inden-7-ones. NMR parameters, thus obtained, are discussed in connection with molecular structures and properties. The structures were partly confirmed by NOE measurements. The signs of all coupling constants observed for six compounds were determined by a selective decoupling technique (except for one with a small magnitude). A deshielding effect of the carbonyl group to a particular 19F atom has also been obtained; it is useful for a structural determination.
Crystal Structure of Trichloroacetamide and Inequivalent Reorientations of CCl3 Groups in the Crystal
Authors: Hashimoto Masao , Hamada Kensaku , Mano Koichi
Published: July 2006

The crystal structure of trichloroacetamide has been determined by the single crystal X-ray diffraction method. Intermolecular contacts have been found to be responsible for the inequivalent reorientations of the CCl3 groups of two crystallographically-independent molecules in the crystal.
Synthesis of Shikalkin (±Shikonin) and Related Compounds
Authors: Terada Akira , Tanoue Yasuhiro , Hatada Akira , Sakamoto Hiroshi
Published: July 2006

The key intermediate, 2-formyl-1,4,5,8-tetramethoxynaphthalene, was prepared through 1,4,5,8-tetramethoxynaphthalene, which was obtained from 1,5-naphthalenediol via three steps or from naphthazarin via one step. A total synthesis of shikalkin and dihydroshikalkin have been accomplished with this aldehyde via a side-chain introductions with Grignard reactions and the following demethylations.
Hydrogenation of Carbon Monoxide over Solid Catalysts Dispersed in the Liquid Medium. I. Slurry-Phase Fischer–Tropsch Synthesis with Supported Ruthenium Catalysts
Authors: Fujimoto Kaoru , Kajioka Masahiko
Published: July 2006

Fischer–Tropsch synthesis on supported ruthenium catalysts were operated successfully in the slurry phase, using ethyl cyclohexane solvent, in spite of the high selectivity of waxy products. Titania, fumed silica, and Nb2O5 were found to be excellent carriers for ruthenium. A Ru/SiO2 catalyst yielded a hydrocarbon product with the rate as high as 600 mg(g-cat)−1h−1 at 240°C and 40 bar. The optimum metal loading was 2% by weight. Calcination of the catalyst precursor at 300°C or above caused a marked decrease in the metal dispersion, which was essential for the high catalytic activity and chain-growth ability. The maximum chain-growth probability obtained on a calcined Ru/Al2O3 catalyst was 0.94.
Direct Determination of Absolute Light Intensity in UV-Transmitting and UV-Dispersive Fluoro Polymer Tubes
Authors: Funayama Hitoshi , Sugawara Takuo
Published: July 2006

To determine the absolute light intensity (including the reflective, scattered, and incident light intensity) in a UV-transmitting and UV-dispersive fluoro polymer tube, a new chemical actinometer, DPOF system, was introduced which was composed of dilute potassium tris(oxalato)ferrate(III), 0.03 mol m−3; 1,10-phenanthroline, 0.135 mol m−3; and potassium oxalate, 1.5 mol m−3. The overall light intensity was determined with a simple procedure based on a precise analysis of the photochemical kinetics of a DPOF system. The absolute intensities at 366 nm in the UV-transmitting and UV-dispersive Teflon FEP and Folaflon PVdF tubes were detected to be higher than that in a fused-silica tube of similar size while the incident light intensities in the former tubes were always lower than that in the latter. In addition, the dispersive effect of a Teflon FEP tube was rather independent of the wall thickness and the tube diameter under the experimental conditions studied, owing to its high dispersibility of light. The dispersive effect was much more remarkable for the Folaflon PVdF tube. The property of light transmission with dispersion, with the characteristic of antifouling, would make the fluoro polymer tubes useful for novel photoreactors in various areas.
Activation of C–H Bonds of Heterocyclic and Alicyclic Compounds Using Calcium Atoms
Authors: Mochida Kunio , Kojima Kenji , Yoshida Yasuhiro
Published: July 2006

Calcium atoms have been inserted into C–H bonds of heterocyclic (furans and thiophene) and alicyclic compounds (cyclohexanes and cyclopentane) to give the corresponding organocalcium hydrides. The organocalcium hydrides thus produced reacted with trimethylchlorosilane to give trimethylsilyl-substituted heterocyclic and alicyclic compounds, and a reduced product (trimethylsilane).
A Convenient Method for the Synthesis of Alkylsilyl Cyanides Using Potassium or Sodium Cyanide Impregnated on Amberlite XAD Resin
Authors: Sukata Kazuaki
Published: July 2006

Potassium and sodium cyanide impregnated on Amberlite XAD resin were found to be effective for converting alkylsilyl chloride to the corresponding alkylsilyl cyanide under mild conditions.
Synthesis of Sterically Hindered Bicyclo[2.2.2]octanes by Lewis Acid Catalyzed Reaction of 2-(Trimethylsiloxy)-1,3-cyclohexadienes with 4-Methyl-3-penten-2-one
Authors: Asaoka Morio , Ishibashi Keiji , Takahashi Wataru , Takei Hisashi
Published: July 2006

Dienol silyl ethers of various 2-cyclohexenones reacted with 4-methyl-3-penten-2-one(mesityl oxide) or methyl acrylate in the presence of Lewis acid to give bicyclo[2.2.2]octanes in moderate yields.
New Flavonoids Isolated from Infected Sugarbeet Roots
Authors: Takahashi Hajime , Sasaki Teruji , Ito Masaaki
Published: July 2006

New flavonoid compounds, 3,5-dihydroxy-6,7-methylenedioxyflavanone, 2′,5-dihydroxy-6,7-methylenedioxyisoflavone, and 5-hydroxy-6,7-methylenedioxyflavone were isolated from sugarbeet roots infected with Rhizoctonia solani.
Silaethene in Pyrolysis of Spiro[silacyclobutane-1-9′-[9H-9]silafluorene]
Authors: Terunuma Daiyo , Nakamura Makoto , Miyazawa Eiji , Nohira Hiroyuki
Published: July 2006

A new silaspiro compound, i.e., spiro[silacyclobutane-1,9′-[9H-9]silafluorene](1) was synthesized in 75% yield. It was found that the pyrolysis of 1 at 650°C under a reduced pressure gave a head-to-tail silaethene dimer in 15% yield. Copyrolysis of 1 in the presence of benzophenone gave 1,1-diphenylethene and a siloxane oligomer in 50 and 30% yield, respectively.
The Preconcentration and Determination of a Trace Amount of Strontium in Fresh Water as Its 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone Chelate by Means of Solvent Extraction
Authors: Honjo Takaharu , Nakata Takashi
Published: July 2006

The behavior of a trace amount of alkaline earth metals (magnesium, calcium, strontium, and barium) on solvent extraction has been examined with PMBP (1-phenyl-3-methyl-4-benzoyl-5-pyrazolone) in benzyl alcohol; the results have also been applied to the preconcentration and determination of a trace amount of strontium in ppb order in fresh water as its PMBP chelate by means of solvent extraction.
Photochemical Synthesis of η-Acetylene Complex of an Orthometalated Manganesecarbonyl Derivatives, (PhO)2(

Remark: Graphics omitted.

)(CO)3(PhC≡CPh), and Its Structural Study by 13C and 31P NMR Spectroscopies
Authors: Onaka Satoru , Furuichi Nobuhiro , Tatematsu Yukinobu
Published: July 2006

Photochemical reaction of an orthometalated manganesecarbonyl derivative, (PhO)2(Remark: Graphics omitted.)(CO)4 with PhC≡CPh in benzene yielded (PhO)2(Remark: Graphics omitted.)(CO)3(PhC≡CPh) and its structure was studied by 13C and 31P NMR spectroscopy based on 13C and 31P NMR data for relevant orthometalated metal carbonyl derivatives including (o-CH3C6H4O)2(Remark: Graphics omitted.)(CO)3P[OC6H4(CH3)]3 which was first synthesized in this study.
Favorskii-Type Rearrangement of α,α′-Dihalo Ketones with Sodiomalonates Leading to Conjugated Enone Derivatives
Authors: Sakai Takashi , Ishikawa Mutsumi , Amano Eiichiro , Utaka Masanori , Takeda Akira
Published: July 2006

A new synthetic method of conjugated enones by the use of carbanion-induced Favorskii-type rearrangement is described. The reaction of α,α′-dihalo ketones R1R2(X)CC(O)CH2X with sodiomalonates Na+  −CR3(CO2R4)2 in THF at 0°C—room temperature gave conjugated enones R1R2C=CHC(O)CR3(CO2R4)2 in 42–66% yields. The reaction can be also adaptable to the enolates of ethyl cyanoacetate or malononitrile to give the corresponding enones.
Partially Benzylated Derivatives of 6-Deoxy-d-glucose
Authors: Koto Shinkiti , Morishima Naohiko , Mori Yoko , Tanaka Hitoshi , Hayashi Seiichi , Iwai Yumi , Zen Shonosuke
Published: July 2006

Several partially benzylated derivatives of 6-deoxy-d-glucose (d-quinovose) were synthesized from appropriate di-O-benzyl-d-glucosides whose primary hydroxyl group is unprotected, via unimolar tosylation and subsequent reduction with LiAlH4.
Spin-Trapping of Alkyl Radicals by a Water-Soluble Nitroso Aromatic Spin-Trap, 3,5-Dibromo-4-nitrosobenzenesulfonate
Authors: Ozawa Toshihiko , Hanaki Akira
Published: July 2006

Some short-lived alkyl radicals generated by the oxidation with either Ti3+–H2O2 or Fe2+–H2O2 system were trapped by a water-soluble nitroso aromatic spin-trap, 3,5-dibromo-4-nitrosobenzenesulfonate (DBNBS, 1), in aqueous solutions to yield the stable spin-adducts which could be easily detected and identified by electron spin resonance (ESR) spectroscopy.
Studies of Collectors. VIII. The Flotation of the Gallium Ion with Oxine-Type Surfactants
Authors: Koide Yoshifumi , Hokonohara Hisashi , Jinnai Kuniaki , Yamada Kimiho
Published: July 2006

Oxine-type surfactants(5-alkanoyl-8-quinolinol, RnOx, n=2, 8, 12, 18) and R12OOX were prepared and used as ion-flotation collectors. Cu2+, Fe3+, Zn2+, and Pb2+ were floated with R12Ox around a neutral pH, and the selective removal of Cu2+ from the mixture of these four metal ions was observed at pH 1.0. The floatability of Ga3+ was also high around the neutral pH, and the selective Ga3+ flotation from an Al3+ (100 ppm)–Ga3+(20 ppm) mixture was observed by using R8Ox in the pH regions of 3–4 and 10–13.3 (0.2 M NaOH soln), while R12Ox did not float the Ga3+ so much at pH 10–13.3. By the addition of a small amount of RnPy to the R12Ox or by the solvent sublation, an effective flotation of Ga3+ was observed in the pH range of 10–13.3. The Ga3+ flotation was superior to the Ga3+ extraction in pH 2–4. However, in a strong alkaline region the floatability was lower than the extractability.
Reaction Mechanism for Selective Synthesis of Gasoline-Range Isoalkanes from Syngas over RuPtHY Zeolites. II. Role of Metals and Acid Sites
Authors: Shul Yong-Gong , Arai Yukari , Tatsumi Takashi , Tominaga Hiro-o
Published: July 2006

Role of metals and acid site in selective synthesis of gasoline-range isoalkanes from syngas catalyzed by zeolite Y supported Ru–Pt alloy has been studied. As a probe molecule 1-alkene was added into syngas over the various combination of catalysts. Alloying Ru with Pt enhanced 1-octene conversion as well as CO conversion. Reaction of 1-octene over metal-free DAHY (dealuminated HY) zeolite produced cracking products with high selectivity for isobutanes; C3+ carbon number distribution was similar to that from CO hydrogenation over DAHY2R2P (Ru and Pt 2 wt%, respectively), suggesting that the selective formation of isoalkanes in gasoline-range from CO–H2 over DAHY2R2P could be essentially due to acid-catalyzed reactions on zeolites. Cracking of 1-octene was affected by the support and increased in the order: NaY2R2P<HY2R2P<DAHY2R2P. Products via disproportionation were predominant for NaY2R2P and HY2R2P and those via simple cracking prevailed in DAHY2R2P. This could account for shift to light side in carbon number distribution from simple CO hydrogenation over DAHY2R2P. From syngas H2/CO ratio=13/2, methane was the main product. However, methane production was virtually unchanged on addition of 1-octene, implying that the presence of CO suppressed the hydrogenolysis of 1-octene on RuPt bimetallic site. Effects of contact time and temperature on selectivity for products were also discussed.
Cross Sections for the Quenching of Hg(6s6p1P1)
Authors: Umemoto Hironobu , Kasakura Akeo , Kikuma Jun , Sato Shin
Published: July 2006

Absolute cross sections for the quenching of Hg(6s6p1P1) by simple molecules were measured by employing a Stern–Volmer type intensity measurement combined with a phase-shift measurement of effective radiative lifetime. The cross sections are approximately gas kinetic, except for rare gas atoms and tetrafluoromethane. The cross sections can be correlated with the C6 long-range force parameter to the power 0.52.
ESR and Mass-Spectrometric Studies of Methanol Combustion. III. The Effect of CS2 and CH3NH2 Additions on the Concentration Profiles of Chemical Species in a Methanol–Air Flame
Authors: Taniguchi Masayuki , Hirasawa Nobuhito , Yoshida Hiroshi
Published: July 2006

The concentration profiles of chemical species (labile and stable) in methanol–air free-burning flames with and without the addition of CS2 and CH3NH2 have been examined by means of the probe-sampling ESR method, combined with mass-spectrometric measurements. In addition to the principal labile intermediates (H, O, and OH) and stable species (CH3OH, O2, H2, CH2O, CO2, and H2O), SO2 and NO have been detected from the flame when it has been doped with CS2 or CH3NH2 respectively. The observed results indicate that the addition of these dopants depresses the concentration of OH and raises the concentration of H2 in the primary reaction zone, where SO2 and NO are efficiently generated. The observed concentration profiles have been discussed in terms of the reaction mechanism of the oxidation of sulfur and nitrogen compounds.
A Localized Molecular Orbital Approach to Bond Moment Theory. II. The Transferability of Bond Moment Derivatives
Authors: Shinoda Hiroyuki
Published: July 2006

The transferability of bond moment derivatives(BMDs) in the bond moment theory was investigated by the use of localized molecular orbitals derived from INDO canonical orbitals. Five series of molecules were treated, two for a terminal C–H stretching motion and three for an O–H one. It is concluded that the transferability of BMDs with significant values is recognized among the molecules which have the same structure within the second neighbor bonds; it is also concluded that the changes in the molecular moiety beyond the third neighbor bonds slightly affect the BMDs of all the bonds, with the exception of the stretching one. These conclusions were confirmed by theoretical considerations, such as perturbation expansion.
The Pyrolysis of Heptathiazocine
Authors: Kudo Yoshiyuki , Hamada Shuichi
Published: July 2006

Heptathiazocine was pyrolyzed into ammonia, tetrasulfur tetranitride, and tetrasulfur dinitride above 383 K in an argon atmosphere; then, the latter two intermediates finally degraded into sulfur and nitrogen. According to the stoichiometric correlation among the final pyrolytic products, an overall pyrolysis can be expressed as: S7NH=7/8 S8+1/3 N2+1/3 NH3. The differential scanning calorimetry of heptathiazocine gave the standard enthalpy of the formation as 89.3±1.1 kJ mol−1 by combining the enthalpy change of the pyrolysis with its molar heat capacity and known thermodynamic data of the concerned species. The standard enthalpies of the formation of this compound were also calculated as being 93 and 91 kJ mol−1 on the basis of Sanderson’s method, assuming that hydrogen bonds were negligible in the crystal (which were comparable to that observed in this work).
Redox-Photosensitized Reactions. XV. Photosensitized and Direct Photolytic Isomerizations of the Tetrahydro Dimers of 1-Benzylnicotinamide
Authors: Ishitani Osamu , Yanagida Shozo , Takamuku Setsuo , Pac Chyongjin
Published: July 2006

The photosensitization by either [ReBr(bpy)(CO)3] or [Ru(bpy)3]2+ (bpy=2,2′-bipyridine) resulted in the isomerization of 1,1′dibenzyl-1,1′,4,4′-tetrahydro-4,4′-binicotinamide (1) and 1,1′-dibenzyl-1,1′-tetrahydro-4,6′-binicotinamide (2) to give a common mixture of 1, 2, and the diastereoisomer of 2 (3) in a 2:2:1 ratio at a photostationary state, while either direct photoexcitation or thermal activation effected only the isomerization of 2 to 1 but not at all the retro isomerization.
The Synthesis of (15R)-Coleon C and (15S)-Coleon C
Authors: Matsumoto Takashi , Imai Sachihiko , Yoshinari Takashi
Published: July 2006

(15R)-11,16-Dihydroxy-12-methoxymethoxy-8,11,13-abietatrien-7-one and its (15S)-epimer prepared from a C-15 epimeric mixture of 12-methoxy-8,11,13-abietatrien-16-ol, were transformed into (15R)-6,11,12,14,16-pentahydroxy-5,8,11,13-abietatetraen-7-one and its (15S)-epimer; these were identical with natural (15R)-coleon C and (15S)-coleon C, respectively.
Pyrolysis of Sulfoxide Bearing Electron-Withdrawing Substituents on β-Position in S-Ethyl Group of Ethyl Phenyl Sulfoxide
Authors: Yoshimura Toshiaki , Yoshizawa Masaki , Tsukurimichi Eiichi
Published: July 2006

In order to obtain information concerning the reaction mechanism of the pyrolysis of a sulfoxide bearing an electron-withdrawing substituent on the β-position in the S-ethyl group of ethyl phenyl sulfoxide, 2-(substituted phenyl)ethyl aryl sulfoxides(1) and 2-cyanoethyl (substituted phenyl) sulfoxides(2) were pyrolyzed. The rate-enhancing effect of the β-phenyl group of 1 was small. The activation enthalpy and entropy of 1 were found to be 110 kJ mol−1 and −45 JK−1 mol−1, respectively. Hammett plots for 1 gave positive trends for the substituents, both on the β-phenyl group (ρ=0.76) and on the S-phenyl group (ρ=0.32), though the ρ-value of the latter was about half of the former. On the other hand, the Hammett plot for 2 did not give a straight line, but a concave curve in which a series of substituents from the p-OCH3 to p-Cl groups gave a negative trend (ρ=−0.49), while the p-NO2 group afforded a positive trend. The pyrolytic rate of 2 was found to be about 23-times faster than that of 1 at 100 °C. The kinetic isotope effect for β-position hydrogen in the β-phenylethyl group of 1 was considerably large (kH⁄kD=4.3). From the obtained results, it was suggested that the pyrolysis of 1 and 2 proceeds via a nearly carbanion-like mechanism in a five-membered cyclic transition state.
Synthesis and Electrochemical Properties of 3-(3,6-Dioxo-1,4-cyclohexadienyl)methyl-p-tropoquinone. Analysis of a Four-Electron Redox System by Cyclic Voltammetry
Authors: Mori Akira , Goto Yasutomo , Takeshita Hitoshi
Published: July 2006

A methylene-linked bisquinone, 3-(3,6-dioxo-1,4-cyclohexadienyl)methyl-p-tropoquinone, was prepared from 2,5-bis(arylmethoxy)tropone by consecutive reaction, a homolytic rearrangement, subsequent debenzylation, and a DDQ–dehydrogenation. According to cyclic voltammetry, this four-electron redox system was operative, in sharp contrast to the case of the benzenoid bisquinones, via four successive one-electron transfer processes. Two other tropolone derivatives carrying p-benzoquinone segment were also prepared by a similar procedure. The first reduction potentials of these benzoquinones showed a slight enhancement by intramolecular hydrogen bonding.
Preparation of 2-Alkenylsilanes and 2-Alkenylstannanes by the Reaction of 2-Alkenyl-1,1-cyclopropanedicarboxylate Esters with PhMe2SiAlEt2 and (Ph3Sn)2Zn. Generation of 2-Alkenyl-3-cyclopentene-1,1-dicarboxylates via Alkenyl Substituted π-Allylpalladium Complexes Derived from Dienylsilanes and [PdCl2(CH3CN)2]
Authors: Fugami Keigo , Oshima Koichiro , Utimoto Kiitiro , Nozaki Hitosi
Published: July 2006

Reaction of 2-vinyl-1,1-cyclopropanedicarboxylate with PhMe2SiAlEt2, PhMe2SiZnEt2Li, or (Ph3Sn)2Zn gave 1,7-homoconjugate addition products, 2-alkenylsilanes or 2-alkenylstannanes. In a similar fashion, 2-(1,3-butadienyl)-1,1-cyclopropanedicarboxylate provided the corresponding 1,9-homoconjugate adducts, dienylsilanes or dienylstannanes. The adducts were converted into π-allylpalladium complexes by means of [PdCl2(CH3CN)2]. Treatment of the alkenyl-substituted π-allylpalladium complexes derived from dienylsilanes and [PdCl2(CH3CN)2] with bases such as PPh3 or Na2CO3 gave 2-alkenyl-3-cyclopentene-1,1-dicarboxylates. In contrast, the reaction of the π-allylpalladiums generated from 2-alkenylsilanes and [PdCl2(CH3CN)2] with the bases resulted in the formation of original vinylcyclopropane derivatives.
Novel Effect of Additives on the Quenching Mechanism of the Excited State of Copolymer-Pendant [Ru(bpy)3]2+ by Methylviologen in Methyl Alcohol
Authors: Kaneko Masao , Hou Xiao-Huai , Yamada Akira
Published: July 2006

The quenching of the excited state of acrylic acid copolymer-pendant [Ru(bpy)3]2+ by methylviologen (MV2+) was studied in methyl alcohol. The Stern–Volmer plots for the quenching showed a line or a curve (downward or upward) depending on the additive such as acid, alkali, or neutral salt in methyl alcohol. This behavior in methyl alcohol is entirely different from that in water where only dynamic quenching occurs. The behaviors in alcohol were analyzed by assuming stepwise binding of MV2+ into the domains around the Ru complex formed by the dissociated carboxylates and by considering dynamic as well as static quenching models. The one kind of photochemical reaction system showed four different quenching mechanisms induced by the additives.
Preferential Solvation of Ni(II) in Water–Solvent Mixtures from 13C NMR Paramagnetic Relaxation Rate
Authors: Kobayashi Kanya , Yokoi Masatoki , Kuroda Shigeki , Kubota Eiji
Published: July 2006

13C NMR spin-lattice relaxation time of carbon atom on methanol, ethanol, 1-propanol, and dimethyl sulfoxide molecules has been measured for solutions of Ni(ClO4)2 in these solvents and their mixtures with water. The comparison of the NMR data for solutions with aqueous mixtures and pure solvents gave the number of organic solvent molecules that locate in the first coordination sphere of Ni2+ ion. The result shows that Ni2+ ion is preferentially hydrated in water–alcohol systems, while in water–dimethyl sulfoxide system, the ion is solvated preferentially with dimethyl sulfoxide.
1H and 13C NMR Studies of Formation and Molecular Dynamics of Methylated-Cyclodextrin Inclusion Complexes with Phenylalanine
Authors: Inoue Yoshio , Kuan Fu-Hua , Chûjô Riichiro
Published: July 2006

The formation and the molecular dynamics of the host-guest inclusion complexes in aqueous solution have been studied for hosts α- and permethylated α-cyclodextrin and permethylated β-cyclodextrin and guest phenylalanine by 1H and 13C NMR spectroscopy. The changes in 1H chemical shift, 1H spin-coupling constant, and 13C spin-lattice relaxation time for the guest phenylalanine on addition of the host cyclodextrin show that they form the inclusion complexes in a similar manner, that is, by insertion of the guest’s phenyl ring into the host’s cavity. The strength of the host–guest dynamic coupling varies with the cavity size of cyclodextrins.
Relations between Gas-Phase Stepwise and Bulk Solvation of Cl− with Water and Aliphatic Alcohols
Authors: Hiraoka Kenzo
Published: July 2006

Higher order clustering reactions of Cl− with H2O and ROH for ROH=CH3OH, C2H5OH, and n-C3H7OH were measured in the gas phase with the pulsed electron-beam mass spectrometer. The general trend is found that the obtained −ΔHn−1,n° and −ΔSn−1,n° increase in the order H2O<CH3OH<C2H5OH<n-C3H7OH. This order is just the opposite to the free energies of solvation of Cl−. This is due to the increasingly more unfavorable entropy changes for the solvation of Cl− in the order H2O<CH3OH<C2H5OH<n-C3H7OH. This is clearly manifested on the increasing entropy changes −ΔSn−1,n° for the measured gas-phase clustering reactions for higher alcohols.
Development of Functionalized Materials Using Organometallic Compounds. IV. Thermal Residual Stresses during the Fabrication of a Ni-Coated Continuous Carbon Fiber Aluminum Composites
Authors: Mikata Yozo , Takahashi Tamotsu , Su Shuenn-Kung , Uchida Yasuzo
Published: July 2006

The thermal residual stresses during the fabrication of a Ni-coated carbon fiber composite are calculated by using two- and four-concentric-circular-cylinders models. The advantage of the CDL (chemical deposition in liquid phase) coating method at low temperature (200 °C), which is using organonickel compounds such as Ni(cod)2 (cod=1,5-cyclooctadiene), over the conventional melted Ni-coating method (1453 °C) has been definitely confirmed from the crack prevention viewpoint.
Zirconium–Bis(triethylamine): A New Class of Chelate Ion and Anion Exchanger
Authors: Rawat Jagdish Prasad , Alam Masood , Aziz Hasan M Abdul , Singh Balbir
Published: July 2006

A new inorganic ion exchanger, zirconium–bis(triethylamine) has been synthesized. The material has been studied for its anion exchange capacity, sorption capacity, Kd values, composition, infrared spectrum and thermodynamic behavior. Analytically important separation of anions have been achieved. Ion exchange equilibria of Cr2O72−, CrO42−, SO42−, S2O32−, and MnO4− systems have been studied at 30, 40, 45, and 60 °C. The exchange isotherms have been measured for both forward and backward reactions with solutions of ionic strength 0.10 by batch process. The isotherms showed S shaped curves. The overall thermodynamic data are also calculated.
Synthesis and Characterization of New Three-Component Ion-Exchange Material: Zirconium(IV) Selenophosphate
Authors: Qureshi Saidul Zafar , Rahman Nafisur
Published: July 2006

Zirconium(IV) selenophosphate has been prepared by adding a mixture which is 0.05 M in sodium selenite and 0.05 M in orthophosphoric acid to a 0.05 M solution of zirconium(IV) bis(nitrate) oxide in different volume ratios at pH 1. Its ion-exchange capacity, thermal and chemical stability, pH titration curves, and chemical composition were studied. Adsorption of some of the metal ions in different solvent systems has been studied. The effect of particle size on the sorption behavior of metal ions has also been studied. The analytical importance of this material has been demonstrated by achieving the eleven quaternary separations of metal ions. A comparison of ion-exchange properties of this material has also been made with some other ion-exchangers.
Titanium Determination under High-Sensitivity Conditions with 2-(5-Chloro-2-pyridylazo)-5-dimethylaminophenol. II. Ternary Compounds of Ti(IV)–H2O2–5-ClDMPAP
Authors: Marini Héctor José , Antón Rosa Isabel , Olsina Roberto Antonio
Published: July 2006

Ti(IV) together with pyridylazo-type reagents and other molecular compounds form ternary complexes that may stand as the basis for analytical methods designed for the quantitative determination of the metal. This paper reports the results obtained by the use of the system Ti(IV)–H2O2–5-ClDMPAP in aqueous ethanolic solutions, and application to routine analyses of Ti(IV) in various types of samples. The spectral characteristics of the complexes formed, the pH ranges appropriate for their formation, ethanol influence, composition and stability have been studied. The complex selected for this analytical work is formed between pH 2.5 and 6.5 with a 1:2:2 Ti(IV)–H2O2–5-ClDMPAP molar ratio. The system fulfils Beer’s law up to a Ti(IV) concentration of 0.7 ppm, working at λmax 534 nm. The molar absorptivity and Sandell index are 4.59×104 dm3 mol−1 cm−1 and 0.0010 μg cm−2 respectively
Synthesis and Fluorescence Analysis of 3-Substituted 7-Dialkylamino-2H-1,4-benzoxazin-2-ones
Authors: Trebaul Claude , Roncali Jean , Garnier Francis , Guglielmetti Robert
Published: July 2006

New benzoxazinone type dyes have been synthesized by the reaction of α-keto esters on 2-amino-5-(dialkylamino)phenols. The obtained 7-dialkylamino-2H-1,4-benzoxazin-2-ones show a strong fluorescence and a large Stokes shift, reaching 183 nm. An effect of 15 various substituents in position 3, together with a solvent effect have been characterized on their absorption and emission bands. Linear free energy relationships allow the tuning of their spectroscopic characteristics over a large spectral range.
A Simple and Convenient Method for the Synthesis of Iminomethylene Analogs of Peptides
Authors: Oyamada Hidekazu , Ueki Masaaki
Published: July 2006

The synthesis of pseudopeptides in which a part of the peptide bonds has been replaced by other isosteric bonds has been studied in order to obtain long-lasting peptide drugs and also to study the structure-activity relationships of peptides with biological activity. A simple and convenient method for the synthesis of pseudo[CH2–NH]peptides was established by improving the conditions for the selective reduction of the peptide bond of N-protected dipeptide esters by borane. Among the ester residues investigated, the t-butyl ester gave the best result. During reactions no racemization occurred. [l-Pheψ[CH2–NH]l-Leu4−5]leucineenkephalin was synthesized in good yield starting from N-benzyloxycarbonyl-l-phenylalanyl-l-leucine t-butyl ester.
The Addition Reaction of Benzynes Generated Electrochemically from Dihalobenzenes with Tertiary Amines
Authors: Egashira Naoyoshi , Takenaga Jun , Hori Fumiaki
Published: July 2006

The electroreduction of dihalobenzenes was carried out in the presence of tertiary amines as benzyne acceptors in DMF–TBAP, giving the addition products in yields of more than 10%. For o-dibromobenzene, the yield of the addition product, N-phenylpiperidine, increased to 21% in the presence of N-ethylpiperidine.
An Application of Factor Analysis to the Electronic Spectra of Iodine in Mixed Solvents
Authors: Nakanishi Koichiro , Maya Kenkichi , Howery D G
Published: July 2006

The electronic spectra of iodine diluted in three kinds of mixed solvents, ethanol–heptane, 1,4-dioxane–cyclohexane, and tetrahydrofuran–cyclohexane have been measured as a function of molar composition in mixed solvents and a factor analysis technique has been applied to interpret the results. The number of different iodine-solvent complexes in ethanol solutions is smaller than that in ether solutions.
Crystal Structure of (+)490CDmer-Bis{bis(3-aminopropyl)aminecobalt(III)} Hexacyanocobaltate(III) Dihydrate, (+)490CDmer-[Co(dpt)2][Co(CN)6]·2H2O
Authors: Ishii Minoru , Umehara Michiko , Harada Kazumasa , Nakahara Masayoshi
Published: July 2006

The structure of optically active title compound was determined by X-ray diffraction. The absolute configuration is trans-δ-NH. A pair of two-fused six-membered rings is extended. The geometry of the octahedron is distorted by the presence of the six-membered chelate rings.
The Synthesis of Heteroaromatic Cations Containing Sulfur or Selenium Atoms
Authors: Shibuya Isao , Nakanishi Hiroshi
Published: July 2006

The dialkylamino-substituted heteroaromatic cations, such as 1,2,4-diselenazolium, 1,2-diselenolium, 1,3,5-selenadiazinium, and 1,3-selenazinium cations, were newly synthesized, and their S-analogs were also obtained through similar procedures.
Substitution Reaction of Organic Halide by Trimethylsilyl Isothiocyanate: Formation of Thiocyanate and Its Rearrangement to Isothiocyanate
Authors: Nishiyama Kozaburo , Oba Makoto
Published: July 2006

The reaction of organic halide with trimethylsilyl isothiocyanate (TMSTC) gave thiocyanate 1 and its isomerized isothiocyanate 2. Details of the substituion and the isomerization reactions were examined.
Normal- and High-Pressure Diels–Alder Reactions of p-Tropoquinone with Furans
Authors: Tsuda Tohru , Sugiyama Shigeru , Mori Akira , Takeshita Hitoshi
Published: July 2006

The Diels–Alder reactions of p-tropoquinone with furans were investigated under normal- and high-pressure conditions. With furan or 2-methylfuran, no cycloadduct was obtained at all, but with 2-methoxyfuran, a double Michael adduct was isolated from the reaction under the atmospheric pressure, and its structure was elucidated mainly by 1H NMR analysis. With 3,4-dimethoxyfuran, an exo-1 : 1-adduct and its further reacted 2 : 1-adduct were isolated.
Substitution-Type Thermal 1,2-Rearrangement. Synthesis of Chiral β-Aryl(or Alkenyl) α-Oxo Nitrile Acetal
Authors: Honda Yutaka , Tsuchihashi Gen-ichi
Published: July 2006

Title compound was synthesized via a substitution-type thermal 1,2-rearrangement accompanied by introduction of a cyano group, and derived into the corresponding aldehyde, alkanoic acid, and amide.
Some Unusual Phase Transitions of Nickel(II) Diamine Complexes
Authors: Roy Sukumar , De Goutam , Chaudhuri Nirmalendu Ray
Published: July 2006

[NiX2(tn)2], (tn=1,3-propanediamine; X2=Br2, SO4, or SeO4) undergoes phase transitions upon heating and reverts to their original structure upon cooling. These transitions have been investigated by differential scanning calorimetry and infrared spectroscopy. Earlier, we reported the thermally induced phase transitions of nickel(II) diamine complexes. Most of these phase transitions are time dependent reversible type and the extent of reversibility are found to be catalyzed by humid atmosphere. [Ni(tn)3]X2 and [NiX2(tn)2]·H2O (X2=Cl2, Br2, SO4 etc.) were found to decompose through bis and monodiamine steps. We isolated and characterized all the possible intermediates. But we did not carry out thermal studies of these intermediates from the room temperature. This communication reports some new and interesting reversible phase transitions of [NiX2(tn)2] (X2=Br2, SO4, or SeO4).
Fluorenone Monomer Dianion Studied by 1H and 13C NMR and Charge Density Distribution
Authors: Hirayama Masatoshi , Ohhata Hiroshi
Published: July 2006

The diamagnetic monomer dianion of fluorenone was prepared from 1,2-dimethoxyethane solution of neutral molecule in contact with excess sodium metal at −5 °C for 5 days and its 1H and 13C NMR spectra were measured. The possibility that a pinacolate-type dimer dianion occurs in an equilibrium system was ruled out from reactivity with oxygen, water, deuterium oxide, and reducible aromatics in addition to the analysis of NMR spectra. The charge density distribution of neutral and dianion molecules was estimated by MO calculations. Comparison between experimental and theoretical 13C shifts suggested a strong interaction of sodium ions with carbonyl group. It is presumed that an anormalous diamagnetic ring current in 14π-peripheral structure is responsible for poor correlation between theoretical and observed 1H shifts.
Oxidation of Ketones over Metal Oxide Catalysts. II. Biacetyl Synthesis over Co3O4-Lanthanoid Oxide Catalysts
Authors: Takita Yusaku , Hori Fumiaki , Yamazoe Noboru , Seiyama Tetsuro
Published: July 2006

The effects of the addition (10 atomic%) of lanthanoid oxides into Co3O4 on the oxidation of methyl ethyl ketone (MEK) were studied. The addition of La2O3 brought about marked enhancement of the rate of biacetyl (BA) formation. MEK conversion increased by a factor of 2.8 and the BA selectivity was improved at 450–500K owing to the suppression of deep oxidation. The addition of CeO2 much improved the MEK conversion but BA selectivity decreased to less than 50% and the scission reaction leading to acetaldehyde and acetic acid was enhanced. The addition of Pr6O11 improved MEK conversion but the addition of Nd2O3, Gd2O3, or Er2O3 showed little effect on MEK conversion. The reduction of both scission reaction and deep oxidation and the compensative increase in BA selectivities were observed. An approximately linear relationship was found between the specific rate of BA formation of the catalysts and logarithmic solubitity product constants of hydroxides of tervalent lanthanoid elements added, suggesting that the basicity of the catalysts is one of major factors for BA formation. The maximum efficiency (23.4%) of BA formation was attained at a La content of ca. 10 at.%.
The Structure of the Cyclodextrin Complex. XX. Crystal Structure of Uncomplexed Hydrated γ-Cyclodextrin
Authors: Harata Kazuaki
Published: July 2006

Crystal structure of uncomplexed γ-cyclodextrin, C48H80O40·14.1H2O, was determined by the X-ray method. The crystal is monoclinic and the space group is P21 with cell dimensions; a=16.847(2), b=11.098(2), c=20.271(2) Å, and β=104.97(1)°. The structure was solved by the inspection of a Patterson map and the R-map method combined with the rigid-body least-squares technique and refined by the block-diagonal least-squares method to the R-value of 0.061 for 5099 reflections (sinθ⁄λ≥0.57). γ-Cyclodextrin is in a round shape and somewhat distorted from the regular octagonal symmetry. Intramolecular hydrogen bonds are formed between adjacent glucose residues and maintain the round structure of γ-cyclodextrin. γ-Cyclodextrin molecules are arranged in a cage-type packing, and 7.1 water molecules, occupying 14 sites, are located within the host cavity.
Effects of Some Additives on Proton-Transfer Reaction Studied by Ultrasonic Methods
Authors: Yoshida Yukio , Nishikawa Sadakatsu
Published: July 2006

Ultrasonic absorption and velocity were measured in aqueous solutions of propylamine at 25 °C both in the absence and in the presence of 2 g dm−3 PVA(poly(vinyl alcohol)), 5 mol dm−3 urea and 1 mol dm−3 NaCl. No excess absorption was observed in these solutions without propylamine. A single relaxational absorption was observed in the concentration range from 0.0196 to 0.719 mol dm−3 of propylamine both in the presence and absence of the additives. The ultrasonic parameters have been found to be quite dependent on the concentration of propylamine and also on the structure of additives. This relaxational absorption has been attributed to the perturbation of an equilibrium associated with a proton-transfer reaction. The rate constants and the standard volume change of the reaction have been determined from the concentration dependences of the relaxation frequency and the maximum excess absorption per wavelength. As a result, it was discovered that the forward rate in a solution with PVA increased and those with urea and NaCl, on the other hand, decreased; also, the standard volume change associated with the reaction increased in a series of the solutions with urea, no additive, NaCl, and PVA. The data have been interpreted by means of the structural changes of the solvent water.
A Linear Response Polarizability Theory for an Extended Fano–DeVoe Model with Comments on the Joint Use of Both Short- and Long-Range Inter(sub)molecular Interaction Approximations
Authors: Ito Hirotoshi , I’Haya Yasumasa J
Published: July 2006

An approach to extend the Fano–DeVoe model is presented for copolymer systems by making use of the Green’s operator method within the dipole–dipole approximation. We derive a model Hamiltonian for a system by expanding its primitive Hamiltonian in terms of a bare complete basis set consisting of zero-order one-site and two-site excitation states in the first-order perturbation theory. A generalized extension of the Fano–DeVoe theory can be given by the polarizability tensor derived for this model Hamiltonian. As a more refined way, we derive another model Hamiltonian by expanding the primitive Hamiltonian of the system in terms of the corrected complete basis set consisting of the first-order excitation states. With such model Hamiltonians, we can fabricate polarizability theories on the same footing with the exciton wave function approaches based on the usual perturbation theory. Simplified schemes for the latter model Hamiltonians are applied to the copolymer system consisting of such chromophores that have permanent dipole moments in their ground states. Even if the constituent chromophores do not have permanent moments, extension of the Fano–DeVoe model is made by allowing for the total polymer ground state wave function corrected in terms of two-site excitation states. To circumvent the deficiency of the dipole approximation in the region of short separations of submolecules, we show a recipe as to how to make use of the monopole approximation together with the dipole approximation in conformity with the compromized idea of Moffitt.
Preparation and Time-Resolved in Situ Reflection Spectra of Bilayer Electrodes with Polythiophene Outer Layers
Authors: Murao Kenji , Suzuki Kazuhiro
Published: July 2006

Bilayer electrodes, Pt/poly-1/polythiophene [1: tris(4-vinyl-4′-methyl-2,2′-bipyridine)ruthenium(II) perchlorate], where polythiophene is derived from poly(3-methylthiophene) [poly(3-methyl-2,5-thienylene), abbreviated as PMeT] and poly(2,2′-bithiophene) [poly(2,2′-dithienyl-5,5′-ene), abbreviated as PBT], have been prepared. Electropolymerizations of MeT and BT at Pt/poly-1 occur at the platinum electrode surface, followed by phase separation of the polymer components which results in the bilayer structure. Significant imbalance, observed between charge densities involved in the cathodic and anodic waves of the cyclic voltammogram for Pt/poly-1/PBT, is explained as being due to the positive charge leakage from the PBT layer to the platinum substrate through the 2+/3+ redox level of the intervening poly-1 during the potential sweep in the negative direction. This charge leakage is ascribed to the consequence of the closely located oxidation potential of PBT to that of the 2+/3+ of poly-1 (E°′=+0.875 V vs. Ag/Ag+). Time-resolved in situ reflection spectra taken at Pt/poly-1/PMeT immersed in electrolytic solutions give evidence for the mediated redox reactions of PMeT by the poly-1 layer. The spectral changes strongly suggest the transient occurrence of polarons during the doping process.
Vapor Phase Fluorination of Silica Surface with Chlorofluoromethanes and CF4
Authors: Okazaki Susumu , Kurosaki Akito
Published: July 2006

For a surface modification, fluorinations of silica samples including a quartz fiber and a commercial glass fiber, were carried out at around 500 °C in a conventional flow reactor. The surface compositions before and after the fluorination were determined by XPS analyses. Among chlorofluoromethanes and CF4, CCl3F was the most effective for fluorination. Surface OH groups were completely removed or replaced by the fluorination. Adsorptions of water vapor, hexane, hexafluoropropene, and octafluorocyclobutane showed that the silica surface became more hydro- and lipophobic after the fluorination. On the contrary, the chlorofluoro-methanetreated surface exhibited a higher affinity to the perfluorocarbons compared to the untreated surface.
A New Detection Method of Electromigrating Ions through a Cation-Exchange Membrane
Authors: Kawaguchi Akihiro , Magaino Shin-ichi , Suzuki Takashi , Takeuchi Yasushi
Published: July 2006

An isotachophoretic analysis and electromigration of ions through a cation-exchange membrane have been investigated. K, Li, Na, and Cu ions were migrated at a constant current. The potential difference between fibrous ion exchanger and cathode reservoir was measured during migration of ion zone. The relative ionic mobility of K+, Na+, Li+, and Cu2+ calculated by potential difference was 1, 0.667, 0.420, and 0.218, respectively. The concentration of mobile cations in unit volume of the membrane was calculated by the amount of migration and the migration time of each ion. The concentration of mobile Li+ in the Li zone was about 10% lower than that of mobile K+ in the K zone. This difference in concentration is similar to the result by the usual isotachophoresis using a capillary tube. The migration time of each ion zone through detection part was proportional to the amount of migration. K+ and Li+ in the concentration range from 0.6×10−3 to 0.2 mol dm−3 were quantitatively determined by the migration time with reproducible errors less than ±5 %.
Properties of Alkali-Free Lead Phosphate Glasses as an Ion-Selective Electrode and Their Application to a Potentiometric Detector for Ion Chromatography
Authors: Nomura Tsuyoshi , Nakagawa Genkichi
Published: July 2006

The properties of alkali-free lead phosphate glasses containing silver oxide as an anion selective electrode were examined, and their application to a potentiometric detector for an ion chromatographic technique were developed. The series of these glasses are characterized by their low softening temperature and are only responsive to anionic substances. The featureless potential response of almost anions tested becomes a rather useful property as a detector for an ion chromatographic analysis of anions. The response characteristics and selectivity coefficients revealed that the glass composition of 10Ag2O : 55P2O5 : 25PbO : 10Al2O3 is the most suitable electrode materisl for anion chromatography. With this glass electrode, nonsuppressed anion chromatographic parameters were studied, including a comparison of an eluent composition, the flow rate and the retention time. This detector could be used in a high pH eluent without any interference of the large blank value. In paticular, the detector was highly sensitive to iodide ions. This may be due to the interaction of iodide ions with silver ions which are involved in membrane materials.
Preparation, Stereochemistry, and CD Spectra of Cobalt(III) Complexes with 1,3-Propanedithiolate and 1,3-Propanedisulfinate. Crystal Structure and Absolute Configuration of (−)460CD-(1,3-Propanedisulfinato)(3,6-diazaoctane-1,8-diamine)cobalt(III) Perchlorate Monohydrate
Authors: Okamoto Ken-ichi , Umehara Hideki , Hidaka Jinsai
Published: July 2006

The cis-α isomers of the 3,6-diazaoctane-1,8-diamine (trien) cobalt(III) complexes with 1,3-propanedithiolate (pdt) and 1,3-propanedisulfinate (pdsi) were selectively prepared and optically resolved. Of these isomers, the crystal structure and the absolute configuration of (−)460CD-[Co(pdsi)(trien)]ClO4·H2O have been determined by X-ray diffraction method. The complex cation takes a Δ-cis-α configuration. The 1,3-propanedisulfinate coordinates to cobalt atom through two sulfur atoms and its chelate ring takes a skew boat form with the λ conformation. The CD spectral behaviors in the d–d transition and the sulfur-to-metal (Co(σ*)←S(σ)) charge-transfer band regions are discussed in relation to the absolute configurations of the cobalt(III) complexes with sulfinate type sulfur donor atoms and the corresponding thiolate ones.