Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
75 巻 , 10 号
選択された号の論文の28件中1~28を表示しています
  • Shinobu Itoh, Shunichi Fukuzumi
    原稿種別: scientific monograph
    専門分野: AI
    2002 年 75 巻 10 号 p. 2081-2095
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Reactions of copper(I) complexes with molecular oxygen have been examined using a series of N-alkyl-bis[2-(2-pyridyl)ethyl]amine tridentate ligands (R′Py2R) and N,N-dialkyl-2-(2-pyridyl)ethylamine didentate ligands (R′Py1R1,R2) at low temperature. The tridentate ligands predominantly provide (μ-η2 : η2-peroxo)dicopper(II) complexes (side-on type peroxo complex), while the didentate ligands enhance O–O bond homolysis of the peroxo species to produce bis(μ-oxo)dicopper(III) complexes. With the (μ-η2 : η2-peroxo)dicopper(II) complexes supported by the tridentate ligand, efficient oxygenation of phenolates to the corresponding catechols has been accomplished to provide a good model reaction of tyrosinase. The bis(μ-oxo)dicopper(III) complexes, on the other hand, undergo aliphatic ligand hydroxylation as well as oxygen atom transfer to sulfides to give the corresponding sulfoxides. In the reaction of bis(μ-oxo)dicopper(III) complex with 10-methyl-9,10-dihydroacridine (AcrH2) and 1,4-cyclohexadiene (CHD), a new active oxygen intermediate such as a (μ-oxo)(μ-oxyl radical)dicopper(III) or a tetranuclear copper-oxygen complex has been suggested to be involved as the real active oxygen species for the C–H bond activation of the external substrates. A mixed valence bis(μ3-oxo) trinuclear copper(II,II,III) complex has also been assessed using the didentate ligand with the smallest N-alkyl substituent (methyl). Mechanistic details of the above reactions as well as ligand effects on the copper(I)-dioxygen reactivity are discussed systematically.
  • Shigenobu Yano, Yuji Mikata
    原稿種別: scientific monograph
    専門分野: AI
    2002 年 75 巻 10 号 p. 2097-2113
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Synthesis, characterizations and stereochemistry of the transition metal complexes containing glycosylamines derived from sugar molecules and polyamines have been investigated. During this study, the intelligent sugar complexes having ion recognition ability, novel sugar transformation reactions promoted by a cooperative effect of calcium ion and monoamines have been discovered. The biological activity of these metal complexes was also investigated. Antifungal nickel(II) complexes derived from amino sugars, and unprecedented sugar-dependent in vivo antitumor activity of carbohydrate-pendant cis-platinum(II) complexes are described in this article. These results suggested that the stereostructure and bioactivity of the sugar-metal complexes can be modified by varying amines and metal ions, and sugar molecules used.
  • Norio Tsubokawa
    原稿種別: scientific monograph
    専門分野: AM
    2002 年 75 巻 10 号 p. 2115-2136
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Recent advances in surface grafting of polymers onto carbon materials, such as carbon black, graphite powder, and carbon fiber, and the application of polymer-grafted carbon materials as a novel functional materials have been mainly reviewed. The grafting of polymers onto the surface was achieved by (1) grafting onto process, (2) grafting from process, (3) polymer reaction process, and (4) stepwise growth by dendrimer synthesis methodology. For the grafting, surface functional groups, such as carboxyl and phenolic hydroxy groups, were used as grafting sites. For example, in the living cationic polymerization initiated by carbon black/ZnCl2 system, carboxyl groups on the surface acted as initiating site and grafting site. In the surface grafting, polycondensed aromatic rings of carbon materials could be used as grafting sites by using ligand exchange reaction of polymers containing ferrocene moieties. It was demonstrated that, by the grafting of polymers onto carbon black surface, the dispersibility in solvent and the surface wettability were readily controlled by pH and temperature. By postgrafting of hydrophilic polymer to grafted hydrophobic chain on carbon black, amphiphilic carbon black was obtained. The applications of crystalline polymer-grafted carbon black as a novel gas sensor material and a positive temperature coefficient material are summarized.
  • Kenji Takizawa, Seiichiro Koda
    原稿種別: technical report
    専門分野: TP
    2002 年 75 巻 10 号 p. 2137-2145
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The b → X emission of electronically excited O2 isolated in Ar solids was observed under the pulsed KrF excimer laser irradiation at 248 nm. The relaxation proceeds along the b → a → b interstate transition. The time evolution of each b → X (v′, v′′) band was fitted by multi-exponential curves. The nonradiative rate is limited at the b → a transition due to the energy gap, which is larger than that of the a → b transition. The relaxation rate constants of individual vibrational levels (v ≤ 8) of the b state were determined. The vibrational quantum number and temperature dependence of the nonradiative rate constants could be explained based on a multiphonon relaxation theory.
  • Takaaki Hosoya, Takashi Ohhara, Hidehiro Uekusa, Yuji Ohashi
    原稿種別: Others
    専門分野: TP
    2002 年 75 巻 10 号 p. 2147-2151
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    When a crystal of N,N-dibenzyl-1-cyclohexenecarbothioamide was exposed to UV light at 263 K, the cell dimensions were gradually changed with retention of the single crystal form. Since the crystal gradually decomposed after 330 h, the irradiation was stopped and the structure was analyzed by X-rays. The thioamide molecule was converted by 65.0% to the thiolactam molecule. The thioamide and thiolactam molecules were observed as a disordered structure in the crystal. The disordered structure clearly indicates that the hydrogen atom of one of the benzyl groups is extracted by one of the olefin carbon atoms of the cyclohexenyl group and that the benzyl carbon atom makes a bond with another olefin carbon to form a thiolactam ring. The mechanism of the ring formation and the chirality of the produced thiolactam are well explained from the reaction cavity.
  • Shigendo Enomoto, Ken-ichi Kumagai, Miki Hasegawa, Michio Kobayashi, T ...
    原稿種別: Introduction
    専門分野: TP
    2002 年 75 巻 10 号 p. 2153-2154
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    A fluorophotometric method was used to obtain equilibrium constants for the formation of a van der Waals molecular complex between fluoranthene and benzene in the ground state. The equilibrium constant for the above-mentioned complex formation is estimated to be 0.13 dm3 mol−1, which compares well with that (K = 0.15 dm3 mol−1) obtained from a traditional electronic absorption method.
  • Mallipattu Sreedhar, Srinivasulu Jayarama Reddy
    原稿種別: Others
    専門分野: AI
    2002 年 75 巻 10 号 p. 2155-2159
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The electrochemical reduction behavior of two dinitroaniline herbicides, Butralin (BN) and Isopropalin (IN), at a mercury electrode is described based on different voltammetric techniques in various buffer solutions at different pH values. The nature of the electrode process has been examined. A reduction mechanism was proposed. Britton–Robinson (BR) buffer of pH 4.0 was found to be best media for the analysis of the compounds. Both standard addition and calibration methods were used for analysis. The detection limits were found to be 6 × 10−8 M (M = mol dm−3) for BN and for 1.5 × 10−8 M for IN. A differential pulse polarographic method was developed for the determination of the herbicides in grains and soils as well as water samples.
  • Anil Naik, Satish Annigeri, Umesh Gangadharmath, Vidyanand Revankar, V ...
    原稿種別: Others
    専門分野: AI
    2002 年 75 巻 10 号 p. 2161-2167
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The preparation of a novel pentadentate binucleating compartmental ligand, 2-hydroxy-5-methylisophthalaldehyde bis(p-methoxy thiobenzoylhydrazone), is described together with the corresponding chloro-bridged cobalt(II), nickel(II), copper(II) and zinc(II) complexes, which were characterized based on spectral, magnetic, thermal and electrochemical studies. Cryomagnetic investigations (77–296 K) reveal a strong antiferromagnetic spin-exchange between the copper(II) ions (J based on H = −2JS1. S2 is 305 cm−1). An electrochemical study of the copper(II) complex shows two distinct quasi-reversible redox peaks (E11/2 = −0.4 and E21/2 = −0.69 V vs saturated calomel electrode), indicating a stepwise reduction of the copper centers (CuIICuII → CuIICuI and CuIICuI → CuICuI). The EPR spectrum is typical of a “rhombic compressed local molecular environment”. The ligand and its copper and zinc complexes exhibit fluorescence at room temperature in DMF. All of the compounds under study were screened for antimicrobial action.
  • Beata Nowicka, Georg Schmauch, Teiji Chihara, Frank W. Heinemann, Masa ...
    原稿種別: Others
    専門分野: AI
    2002 年 75 巻 10 号 p. 2169-2175
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The ion pairs {[Ni(cyclam)]2+[M(mnt)2]2−} (M = Co, Ni: 1a,b), {[Ni(tmc)]2+[M(mnt)2]2−} (M = Co, Ni: 2a,b) and the solvent complexes {[Ni(cyclam)(dmso)2]2+[M(mnt)2]2} (M = Co, Ni, mnt2− = maleonitriledithiolato = (Z)1,2-dicyano-1,2-ethylenedithiolato, cyclam = 1,4,8,11-tetraazacyclotetradecane, tmc = 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane) were isolated and structurally characterised. The nature of the macrocyclic ligand and the presence of coordinating solvents determine whether the dication is present as a tetra-, penta- or hexacoordinated complex. In 1a the tetracoordinated dications and dianions are arranged in a mixed stack structure; the absences of any short contacts and of a mutual ion pair charge transfer band indicate the absence of charge transfer interaction. The highly puckered cyclam ligand will prevent a close approach of the planar bis(maleonitriledithiolato)cobaltate(II). When cyclam is replaced by its tetramethyl derivative tmc, a strong coordinative interaction is introduced as indicated by the structure of 2a. One dianion coordinates to two dications through two trans-cyano groups. The resulting trinuclear dications {[Ni(tmc)][Co(mnt)2][Ni(tmc)]}2+ form segregated columns separated by the non-interacting, remaining dianion. Crystallisation in the presence of a coordinating solvent like dimethyl sulfoxide (dmso) leads to the ion pairs {[Ni(cyclam)(dmso)2]2+[M(mnt)2]2}containing hexacoordinated dications. Magnetic susceptibility measurements at room temperature are in accord with the observed structures. While 1b is diamagnetic, 1a, 2a, 2b, and the two solvent complexes exhibit values characteristic of the isolated ions, in agreement with the absence of any electronic interaction between dication and dianion within the ion pair. Temperature- dependent measurements down to 1.7 K indicate that a weak antiferromagnetic interaction is present in 2a.
  • Teruyuki Hakoda, Shoji Hashimoto, Takuji Kojima
    原稿種別: Others
    専門分野: AI
    2002 年 75 巻 10 号 p. 2177-2183
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    An electron beam (EB) treatment of gaseous trichloroethylene (TCE) in air was studied as a purification method of off-gases containing gaseous chloroethylenes. The model air containing TCE at input concentrations of 5–75 ppmv, detected mostly in actual off-gases, was irradiated with 1-MeV EBs in a gas-flow vessel at 10 L/min under the conditions of atmospheric pressure, 298 K, and different H2O contents. The decomposition of 75 ppmv TCE was also examined in humid air under different O2 contents of 1 × 103–2.1 × 105 ppmv. In the existence of H2O and O2 contents with ≥ 3 × 102 ppmv and ≥ 5 × 103 ppmv, respectively, the decomposition ratios of TCE were enhanced and TCE was decomposed into 83.0 ± 1.5% of dichloroacetyl chloride (DCAC) and 17.5 ± 0.6% of carbonyl chloride (COCl2) independently of the input TCE concentrations based on the carbon balance. Trichloroethylene of 5–75 ppmv was effectively decomposed by the OH radical through Cl-radical chain oxidation under the above-mentioned air conditions.
  • Takumi Konno, Takashi Yoshimura, Gaku Masuyama, Masakazu Hirotsu
    原稿種別: Others
    専門分野: AI
    2002 年 75 巻 10 号 p. 2185-2193
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The reactions of [Co(aet)(en)2](NO3)2 (aet = 2-aminoethanethiolate) or [Co(aese)(en)2](NO3)2 (aese = 2-amino-ethaneselenolate) with AgNO3 in a 2 : 1 ratio in water gave S- or Se-bridged CoIIIAgICoIII trinuclear complexes: [Ag{Co(aet)(en)2}2](NO3)5 ([1a](NO3)5) and [Ag{Co(aese)(en)2}2](NO3)5 ([1b](NO3)5), while the corresponding 1 : 1 reactions produced S- or Se-bridged (CoIIIAgI)n chain complex-polymers: [Ag{Co(aet)(en)2}](NO3)3 ([2a](NO3)3) and [Ag{Co(aese)(en)2}](NO3)3 ([2b](NO3)3). While the mononuclear [Co(aet or aese)(en)2](NO3)2 and the trinuclear [1a or 1b](NO3)5 were racemates, the polymeric [2a or 2b](NO3)3 crystallized as a conglomerate to give optically active crystals of Δ and Λ isomers. The crystal structures of Λ-[2a](NO3)3·H2O and Λ-[2b](NO3)3·H2O were determined by X-ray crystallography. In Λ-[2a]3+ or Λ-[2b]3+, the S or Se atom in each octahedral Λ-[Co(aet or aese)(en)2]2+ unit is bound to two AgI atoms to form a one-dimensional (CoIIIAgI)n zigzag chain. Each AgI atom in Λ-[2a]3+ or Λ-[2b]3+ is closely contacted with NO3 anions, which stabilizes the chiral chain structure. The crystal structure of [1a]5+ was also determined by X-ray crystallography for its ClO4 salt ([1a](ClO4)5·2H2O), which established that [1a]5+ exists as a racemic compound containing both the ΔΔ and the ΛΛ isomers in the crystal. The optically active S- or Se-bridged complexes, ΛΛ-[1a or 1b]5+ and Λ-[2a or 2b]3+, were obtained by the use of Λ-[Co(aet or aese)(en)2]2+ as the starting complex, indicating that the reactions with Ag+ proceed with retention of the absolute configuration of the CoIII chiral center.
  • Habib Firouzabadi, Nasser Iranpoor, Hamid Reza Shaterian
    原稿種別: Others
    専門分野: OB
    2002 年 75 巻 10 号 p. 2195-2205
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The efficient and chemoselective preparation of acetals and ketals from carbonyl compounds, transacetalization reactions, the conversion of epoxides to acetonides, and the preparation of acylals from aldehydes in the presence of catalytic amounts of 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TABCO) are described.
  • Man-Zhou Zhu, Qi-Hua Wu, Guisheng Zhang, Tan Ren, Dexi Liu, Qing-Xiang ...
    原稿種別: Others
    専門分野: OB
    2002 年 75 巻 10 号 p. 2207-2213
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    A series of cationic lipids were designed and synthesized as vectors for gene delivery. The lipids contain a ketal moiety as a linker and a cholesteryl group as a hydrophobic tail. The framework of cholesteryl derivatives could increase the stability of liposomes by stabilizing the bilayers and their complexes with DNA to improve the transfection efficiency. The ketal bonds in lipids should easily degrade in an acidic environment in a cell (pH = 2–5) after transfection, resulting in little toxicity; in the neutral environment outside of cells (pH = 7), they should be stable as gene carriers. Gene transfer experiments in vitro with BL-6, 3LL, 293, 3T3, and Hela cells were performed. The results show that the gene transfection activity of three lipids is quite high, with least toxicity to cells under the experimental conditions.
  • Girija Shankar Chaubey, Simi Das, Mahendra Kumar Mahanti
    原稿種別: Others
    専門分野: OB
    2002 年 75 巻 10 号 p. 2215-2220
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Quinolinium dichromate in sulfuric acid oxidizes heterocyclic aldehydes (2-furaldehyde, 2-pyrrolecarbaldehyde, 2-thiophenecarbaldehyde) to the corresponding acids in a 50% (v/v) acetic acid–water medium. The kinetic data on the rates of oxidation of the substrates have been discussed with reference to the aldehyde hydration equilibria. The kinetic results support a mechanistic pathway proceeding via a rate-determining oxidative decomposition of the chromate ester of the aldehyde hydrate.
  • Weike Su, Bibo Yang
    原稿種別: Others
    専門分野: OB
    2002 年 75 巻 10 号 p. 2221-2224
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The reductive dimerization cyclization of arylmethylenecyanoacetates promoted by metallic ytterbium has been studied. Highly functionalized cyclopentenes were obtained, and the trans, trans-isomers were the major products.
  • Yoshiyuki Takahashi, Ayako Shirai, Takako Segawa, Tatsuya Takahashi, K ...
    原稿種別: Others
    専門分野: OB
    2002 年 75 巻 10 号 p. 2225-2231
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The mechanism of the color development on thermal paper, comprising a fluoran dye (S-205) and a color developer molecule, such as bisphenol A, was elucidated based on spectroscopic analyses (IR, and NMR) on an isolated black-colored compound prepared by a reaction of S-205 and bisphenol A. We propose that this black-colored compound is, indeed, a color-developing complex (CDC) with a definite molar ratio (S-205 : bisphenol A = 1 : 4 ) which has been formed between the open-form S-205 (generated by the cleavage of the lactone ring of S-205: zwitterion) and bisphenol A through hydrogen-bonding. The enthalpy gain associated with the formation of CDC plays an important role for black-color formation on thermal paper.
  • Yoshihiro Miyake, Yoshiaki Nishibayashi, Sakae Uemura
    原稿種別: Others
    専門分野: OB
    2002 年 75 巻 10 号 p. 2233-2237
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Novel optically active diselenides having a chiral oxazoline have been prepared and the structure of one of them is unambiguously determined by X-ray structural analysis. Treatment of a variety of cyclobutanones with 30% H2O2 in the presence of a catalytic amount of the optically active diselenides in tetrahydrofuran or 1,4-dioxane at 0 °C–rt affords the corresponding γ-lactones in up to 92% yield with up to 19% ee. The enantioselectivity of the product is not yet satisfactory, but this is the first example of asymmetric Baeyer–Villiger oxidation catalyzed by chiral organoselenium compounds.
  • Shin-ichi Ueji, Hideyuki Sakamoto, Keiichi Watanabe, Takashi Okamoto, ...
    原稿種別: Introduction
    専門分野: OB
    2002 年 75 巻 10 号 p. 2239-2240
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The enantioselectivity for the lipase-catalyzed esterifications in an organic solvent was found to be enhanced by addition of (+)- or (−)-camphor as a chiral additive. A more remarkable enhancement of its enantioselectivity was brought about by the cooperative effects of two kinds of additives: (−)-camphor and water.
  • Young-Jin Park, Kaoru Igarashi, Tadao Shimizu
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2241-2246
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    A compact consisting of BaTiO4 fibers oriented mostly in one direction was fabricated via piling sheets made by the doctor blade method. After calcination, in the obtained sintered-compact, the shape of individual fibers was 1ost and spherical ceramic grains appeared. Nevertheless the c-axis of micro-crystals of the ceramic was oriented mainly in the direction of the press that had been applied to the green compact in the fabrication process. Although the compacts were calcined at 1250 °C, which is 1ower than the calcination temperature of typical BaTiO3, the densities of the obtained sintered compacts were high because of the addition of mica. The relative dielectric constant of the 2% doped sample was higher by 1000 than that of the undoped matelia1. BaTiO3 doped with mica by 5% had a dielectric constant independent of frequency in the range of 100 Hz to l MHz.
  • Tomoko Tada, Kazuhito Mano, Eri Yoshida, Naoki Tanaka, Shigeru Kunugi
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2247-2251
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    An SH group was introduced at the N-terminal of subtilisin Carlsberg by reacting with 2-iminothiolane·HCl (Traut reagent) in weakly basic media. The obtained subtilisin-SH was coupled with maleimide connected to an amine polymer (poly(allylamine); PAA), both in soluble and insoluble forms, or connected to the N-terminal of another subtilisin molecule. The immobilized subtilisins and subtilisin dimer thus obtained showed higher specificity towards proteineous substrates, although they had lower activities towards a tetrapeptide substrate. Subtilisins immobilized (conjugated) to PAA were more stable against autolytic and thermal disactivation than the intact enzyme.
  • Yasumasa Tomita, Hiroshi Yonekura, Kenkichiro Kobayashi
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2253-2256
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    LiMxMn2−xO4 (M = Cu, Mg and Zn; x ≤ 0.5) was synthesized and the variance of the crystal structure and the electrical conductivity due to the substitution were studied. The crystal structure was changed by substitution, and the lattice constants decreased with x in LiZnxMn2−xO4. Both Zn and Li ions occupied tetrahedral sites. The Li–O bond became longer and Mn–O became shorter with increasing the content. The electrical conductivity for Mg and Zn compounds decreased from 10−4 S cm−1 to 10−7 S cm−1 with an increase in the Mg and Zn content. In the Cu compound, the conductivity was not changed very much. The infrared spectra for the Mg and Zn compounds shifted with x, indicating that the Mn–O bond became shorter and the Li–O bond longer with an increase in x. An XPS study showed a conversion of Mn3+ to Mn4+ with increasing the Mg, Zn or Cu content in these compounds.
  • Nobuko Tsumori, Qiang Xu, Mai Hirahara, Souichi Tanihata, Yoshie Souma ...
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2257-2268
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Detailed IR, Raman, and NMR spectroscopic characterization has been carried out on the group 11 metal carbonyl cations, Cu(CO)n+ (n = 1, 2, 3, 4), Ag(CO)n+ (n = 1, 2, 3), and Au(CO)n+ (n = 1, 2), over a wide range of temperature and in a variety of strong acids. Based on these results their molecular structures were determined and their stabilities are compared and discussed. The active species have been determined to be Cu(CO)2+ (and Cu(CO)3+ as a minor species) instead of the previously assigned Cu(CO)3+, Ag(CO)+ instead of the previously assigned Ag(CO)2+, and Au(CO)2+, respectively, for the copper(I), silver(I) and gold(I) carbonyl cation-catalyzed carbonylation of olefins and alcohols in concentrated sulfuric acid. The reaction mechanism previously proposed for the metal carbonyl cation-catalyzed carbonylation has been modified to involve an olefin-metal-monocarbonyl (e.g., for Ag) or an olefin-metal-polycarbonyl (e.g., for Cu or Au) intermediate.
  • Manabu Igawa, Yohei Narita, Hiroshi Okochi
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2269-2273
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Heavy metal ions can be selectively transported under the concentration gradient across a cation-exchange membrane with a chelating agent in the receiving phase. The selectivity depends on the complex formation constants of the ions with the agent. Metal ions are adsorbed into a cation-exchange membrane via the ion-exchange reaction and diffuse across the membrane. The desorption process is facilitated by the complexation in the receiving phase, which causes a large transport rate across the membrane. A transport equation was established and the theoretical values estimated by the equation and the permeation characteristics values obtained experimentally agreed well with the measured ion flux. The selectivity of the metal ions in the mixed solution is increased in the adequate concentration of the chelating agent in the receiving phase, when the chelate formation reaction may occur competitively between the ions with the agent in the receiving phase. The metal ions in the complex solution can be stripped as free ions across a cation-exchange membrane via the ion-exchange reaction with protons under a concentration gradient of acid.
  • Tomoyuki Itaya, Nagao Azuma, Kenzo Inoue
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2275-2281
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    2,2,4,4,6,6-Hexakis(4-pyridylmethoxy)-2λ5,4λ5,6λ5,-cyclotriphosphazene (PyPN) and 1,4-anthracenedicarboxylic acid (DCA) formed polymeric supramolecules through hydrogen bonding between carboxyl and pyridyl groups. Two supramolecular self-assemblies were obtained: crystals 1 composed of PyPN/DCA = 1 : 2 from DMSO solution, and crystals 2 composed of PyPN/DCA = 1 : 3 from DMF solution. The former is monoclinic, space group P21/n with a = 12.419 Å, b = 24.10 Å, c = 20.794 Å, β = 93.53°, V = 6212 Å3, Z = 4. The X-ray analysis showed that the complementary hydrogen bonding occurs with two DCA molecules, one on each side of the phosphazene ring of PyPN, to give a novel assembly with polymeric structure. The self-assembly obtained from DMF solution seems to take a cylindrical structure composed of an alternating sequence of one PyPN and three DCA molecules and to be packed into a hexagonal arrangement, as suggested by X-ray diffraction data. These results and the inclusion behaviors of the solvent molecules into 1 and 2 are described.
  • Takanori Mizushima, Kenji Nishida, Hironobu Ohkita, Noriyoshi Kakuta
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2283-2288
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    A fume pyrolysis technique using a nickel-containing tetraethoxysilan solution was applied to the preparation of a microporous and highly dispersed Ni/SiO2 catalyst and compared with nickel-loading onto microporous silica by the conventional impregnation and ion-exchange methods. During impregnation, although the microporous structure remained unaltered, large Ni particles were deposited onto the external surface of the silica particles. Although the ion-exchange method resulted in a high dispersion, the process eroded the silica texture and lowered the pore volume remarkably. In contrast, the fume pyrolysis of a spray of a solution consisting of nickel-incorporated siloxane polymers, prepared through an alkoxide procedure, formed a catalyst which had very small Ni particles in micropores of silica. In spite of the same precursory solution, a simple dryness by evaporation led to pore expansion into the mesopore region and a decrease in the Ni dispersion.
  • Kenji Okitsu, Akihiko Yue, Shuji Tanabe, Hiroshige Matsumoto, Yoshihir ...
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2289-2296
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    The sonochemical reduction of gold(III) [tetrachloroaurate(III)] was carried out under various irradiation conditions in an aqueous solution containing only a small amount of 1-propanol. Identical starting materials and the same initial concentrations were used in each preparation. The rates of gold(III) reduction were strongly dependent on the atmosphere, the temperature of the bulk solution, the intensity of the ultrasound, and the distance of the reaction vessel from the oscillator. For example, the rates of reduction under several atmospheres were in the order of CH4 = CO2 < N2 < Ne < He < Ar < Kr, where no reduction proceeded under the CH4 and CO2 atmospheres. It was clearly found that the rates of reduction were influenced by the cavitation phenomenon. Upon irradiation, colloidal gold particles having a surface plasmon absorption were formed, although in the absence of any stabilizers for the gold particles. It was found by TEM observations that the average size of the formed gold particles changed from 30 to 120 nm by selecting the irradiation parameters. The size of the gold particles was closely correlated to the initial rate of gold(III) reduction; the higher the rate of reduction, the smaller the particles. This relationship suggested that the rate of reduction would affect the initial gold nucleation processes. In a 200 kHz standing wave system used in the present study, the strength of the generated shock waves as well as the mechanical effects could be regarded as relatively weak.
  • Satoshi Sato, Ryoji Takahashi, Toshiaki Sodesawa, Nobuyuki Ichikuni, H ...
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2297-2304
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    Fine particles of SiO2-coated Ni metal were prepared by depositing silica on a Ni(OH)2 precipitate in a dissolution–deposition process of silica glass under hydrothermal conditions, followed by calcination and reduction. A fresh precipitate of Ni(OH)2 was heated with a NaOH solution containing several pieces of silica glass chips in a pressure vessel at 100 °C. Silica components dissolved from the glass chips were deposited on the Ni(OH)2 precipitate, and the silica loading increased with increasing the hydrothermal period. Even after calcination at 500 °C, a specific surface area of the resulting SiO2–NiO increased with silica loading, and exceeded 200 m2 g−1. SiO2–NiO, reduced at 500 °C, had a metal surface area as high as 22 m2 g−1. In contrast to the fact that pure Ni(OH)2 readily aggregates during heating, the SiO2-coated Ni(OH)2 particles are protected from agglomerating during the hydrothermal process, calcination, and reduction.
  • Yoshimune Nonomura, Kenkou Kurita, Akio Kashimoto, Hajime Hotta, Toshi ...
    原稿種別: Others
    専門分野: AM
    2002 年 75 巻 10 号 p. 2305-2308
    発行日: 2002年
    公開日: 2002/10/15
    ジャーナル 認証あり
    A novel lubricant material, calcium N-lauroyl taurate (C11H23CONH(CH2)2SO3·0.5Ca, CaLT), has been synthesized and characterized. The powder of CaLT is a plate-shaped crystal with a lamellar structure. CaLT shows superior lubricity as a result of its unique internal and aggregate structure. When the CaLT powder is applied to an artificial skin, the frictional coefficient is favorably lower than that of other solid lubricants of similar type. The frictional coefficient of CaLT decreases rapidly at initial passage and becomes constant when CaLT is repeatedly rubbed onto an artificial skin. The high lubricity may result from disintegration of the powder aggregates, cleavage of the lamellar layers and deformation of the powder particles. This novel lubricant material, CaLT, will be a powerful ingredient of some cosmetic and/or personal-care products in the near future.
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