Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 77 , Issue 10
Showing 1-26 articles out of 26 articles from the selected issue
Accounts
Organic and Biological
  • Kazuhiro Nakasuji, Takashi Kubo
    2004 Volume 77 Issue 10 Pages 1791-1801
    Published: 2004
    Released: October 09, 2004
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    Molecular design and properties of amphoteric redox hydrocarbons are reviewed. Our molecular design is based on a phenalenyl radical, which has a non-bonding molecular orbital with an occupation number of one and is known to behave as a two-stage amphoteric redox system. We have prepared eight amphoteric redox compounds containing two or three phenalenyl units. Cyclic voltammetry showing small E1sum values confirms the high amphotericity of these compounds. The properties of ionic redox species generated are also investigated. At the last part of this account, we show some aspects of a singlet biradicaloid character that originates from a small HOMO–LUMO gap.
Headline Articles
Organic and Biological
Articles
Theoretical and Physical
  • Yasuo Kameda, Motoya Sasaki, Masahiro Yaegashi, Yuko Amo, Takeshi Usuk ...
    2004 Volume 77 Issue 10 Pages 1807-1814
    Published: 2004
    Released: October 09, 2004
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    Time-of-Flight (TOF) and steady state reactor neutron diffraction measurements have been carried out for aqueous 2.5 mol% DL- and L-alanine solutions in order to investigate the differences in intermolecular hydrogen-bonded structure between solutions involving amino acid molecules with different optical activities. The observed difference functions, Δi(Q) and Δiinter(Q), between observed scattering cross sections for DL- and L-alanine solutions with a D content of 96.1% exhibit the first peak located at Q = 2 Å−1 followed by oscillatory features extending up to the higher-Q region. The difference distribution function, Δg(r), obtained from the Fourier transform of Δi(Q), clearly indicates negative peaks at r = 2 and 2.5 Å and a positive one at r = 3.5 Å. Partial structure factors, aHH(Q), aXH(Q), and aXX(Q) (X: O, N, C, HM, and HM′, where HM and HM′ denote methyl and methine hydrogen atoms within the alanine molecule, respectively) for 2.5 mol% DL-alanine solutions are successfully determined from combined analyses of intermolecular interference terms observed for solutions with 96.1, 66.0, and 35.9% exchangeable deuterium content. The nearest neighbor O···Hex and Hex···Hex (Hex: exchangeable hydrogen atom) distances are determined from the least squares fit of the observed partial structure factors, 1.90(1) and 2.48(1) Å, respectively. These values correspond to the positions of negative peaks observed in the present Δg(r) function. The least squares fitting analysis of the observed Δi(Q) revealed that the difference in the coordination number of the nearest neighbor O···Hex and Hex···Hex interactions between the DL- and L-alanine solutions are −0.031(5) and −0.072(5), respectively. It is concluded that the intermolecular hydrogen bonds among solvent water molecules in the DL-alanine solution are ca. 2% weaker than those in the L-alanine solution.
  • Noriyoshi Kimura, Aki Josako, Masataka Kano, Kenji Kisoda, Toshio Mana ...
    2004 Volume 77 Issue 10 Pages 1815-1819
    Published: 2004
    Released: October 09, 2004
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    13C NMR spectra at room temperature and the temperature dependences of 1H T1 in the solid state were measured in [Ni1−xPdxX(chxn)2]X2 (X: Cl, Br; chxn: 1R,2R-cyclohexanediamine; 0.0 ≤ x ≤ 1.0), where antiferromagnetically coupled paramagnetic –X–Ni3+–X–Ni3+–X– chains were formed at x = 0.00, while the mixed-valence –X–Pd2+–X–Pd4+–X– state was made at x = 1.00. 13C signals at α-carbons in chxn coordinating to Pd atoms showed a doublet assignable to Pd2+ and Pd4+ in x = 1.00, while, with a slight decrease of x from 1.00, a clear broadening and a shift to low-field of signals, indicating conversion into the averaged Pd3+ state, were observed. This can be explained by the fluctuation of the Pd valency caused by neighboring paramagnetic Ni3+ sites introduced in small amounts in the 1-D chain. The x dependences of the chemical shifts of β- and γ-carbons are also attributable to the effect from a partial mixing of the paramagnetic Pd3+ sites. The values of 1H T1 and its temperature dependence observed in the ranges of 100–300 K and x ≤ 0.13 for [Ni1−xPdxBr(chxn)2]Br2 could be explained by a model of strong exchange interactions between Ni3+ and Pd3+ as well as Ni3+ sites. Gradual changes in the T1 value and slope with increasing x from 0.00 to 0.93 are attributable to the variation of the exchange interaction value, which depends upon the number of Ni–Ni pairs.
  • Hiromichi Uehara, Koui Horiai, Kazufumi Akiyama
    2004 Volume 77 Issue 10 Pages 1821-1827
    Published: 2004
    Released: October 09, 2004
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    Analytic expressions for Born–Oppenheimer corrections to Dunham’s Yij with optimal fitting parameters, i.e., determinable clusters of expansion coefficients, are applied in analysis of data of reported vibrational–rotational and rotational transitions of HCl. In this method of analysis the choices of a set of fitting parameters and also a corresponding set of Yij that connects the fitting parameters with the term values are unique. A layered structure for empirical parameters Δij is revealed. All spectral lines of four isotopomers of HCl are simultaneously fitted to a single set of molecular constants well within the experimental errors. The approach thus provides a better fit of smaller standard deviations with fewer number of adjustable parameters than from other methods of analysis. The determined values for the coefficients of adiabatic effects s1H and s1Cl reveal the wobble-stretch term to be unimportant in the adiabatic correction for HCl.
Analytical and Inorganic
  • Noriko Suzuki, Megumi Igarashi, Hiromi Suzuki, Mami Itoh, Yu Komatsu, ...
    2004 Volume 77 Issue 10 Pages 1829-1833
    Published: 2004
    Released: October 09, 2004
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    The H+/MA+ ion-exchange reaction of layered γ-titanium and γ-zirconium phosphates, MT(HPO4)2·nH2O, was examined, where MA is an alkali metal and MT is Ti or Zr. They showed remarkably high ion-exchange selectivity for Cs+ and Rb+ in acidic media. The selectivity for Na+ was rather low, and Li+ exchange hardly occurred. The H+ ion exchange of both γ-phosphates with Cs+ and Rb+ apparently occurred in two steps. These ion-exchange reactions occurred first at a pH value of around 2.0 to form a monobasic structure, MTMAH(PO4)2·nH2O, accompanied by dehydration of the water of crystallization. The second step occurred at a pH around 8.0 to form a dibasic structure, MT(MAPO4)2·nH2O, the interlayer space of both γ-phosphates swelled again. The lattice of crystals gradually collapsed corresponding to further progress of the ion-exchange reaction with Cs+ and Rb+, and the amorphous phase finally appeared. According to 133Cs NMR study, Cs+ was found to be rather restricted. The results were compared with those of layered synthetic mica. The high Cs+ and Rb+ selectivity was ascribed to the dehydration property and strong interactions of these ions with the host lamella layers. The high selectivity of two γ-phosphates for Cs+ in acidic media suggested a potentiality as promising materials for the recovery from radioactive waste. The interfering effect of coexisting Fe2+ was scarcely observed upon Cs+ exchange, and was even positive due to the prevention of lattice coagulation.
  • Yanbei Zhu, Masuki Hoshino, Hiroshi Yamada, Akihide Itoh, Hiroki Harag ...
    2004 Volume 77 Issue 10 Pages 1835-1842
    Published: 2004
    Released: October 09, 2004
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    Coastal seawater and river water samples were collected near Nagoya port, located in the coastal area of the Ise Bay, and in six rivers around Nagoya City. The rare earth elements (REEs) in these samples were determined by inductively coupled plasma mass spectrometry (ICP-MS) with chelating resin preconcentration. The concentrations of all REEs except for Pm in coastal seawater and river water samples could be determined at the concentration level from sub-ng L−1 to 10 ng L−1. In order to examine the relative concentration variations, the REE patterns were estimated by normalizing the concentrations of REEs in the water samples to those in Post Archean Average Australian Shale (PAAS). Significantly positive Gd anomalies in the REE patterns were observed for river waters down from the urban areas as well as for coastal seawater. Such Gd anomalies were especially remarkable for river water collected near sewage treatment facilities in the Tenpaku river. It was, thus, concluded that the Gd anomalies in the REE patterns were artificially caused by anthropogenic sources mainly due to recent use of a gadolinium compound as a contrast reagent for magnetic resonance imaging (MRI) in medical diagnosis.
  • Hicham Cavalié-Kosheiry, Amer Hammami, Béatrice Garcia, ...
    2004 Volume 77 Issue 10 Pages 1843-1847
    Published: 2004
    Released: October 09, 2004
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    The electrochemical and spectroscopic properties of a new family of stable radical cations based on 2(3H)-thiazolone azine were investigated. All of the studied compounds display two redox processes, leading to a radical cation, and then to a dication, the radical mono-cation being intensely blue-colored. These properties suggest that this new family of dyes provides excellent candidates for electrochromic devices, such as electrochromic windows, or as redox indicators or mediators.
  • Masanobu Tsuchimoto, Toshio Ishii, Takane Imaoka, Kimihisa Yamamoto
    2004 Volume 77 Issue 10 Pages 1849-1854
    Published: 2004
    Released: October 09, 2004
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    Oxovanadium(IV) and (V) complexes with a pentadentate Schiff base ligand, [VIVO(HL)]·H2O {H3L: N,N′-bis(3-ethoxysalicylidene)-2-hydroxy-1,3-propanediamine} and [VVO(L)]·CH3CN, were prepared by the reaction of the Schiff base ligand with [VIVO(acac)2] (H2acac: acetylacetone) in CH3CN under an argon atmosphere and in air, respectively. IR data of the complexes indicate that [VIVO(HL)] and [VVO(L)] have polymeric (···V=O···V=O···) and monomeric structures, respectively, in the solid state. An X-ray crystal structure analysis of [VVO(L)]·CH3CN was carried out. The complex has a distorted octahedral structure with one of the imine nitrogen atoms trans to the oxo atom. The cyclic voltammogram of [VVO(L)] in CH2Cl2 shows a quasi-reversible V(V)/V(IV) redox couple with E1/2 = −0.74 V vs Ag/Ag+. On the other hand, the cyclic voltammogram of [VIVO(HL)] in CH2Cl2 shows two irreversible oxidation waves at +0.23 and +0.33 V with a scan rate 100 mV/s. The cyclic voltammogram of [VIVO(HL)] in DMSO shows a quasi-reversible V(V)/V(IV) redox couple with E1/2 = −0.05 V. Electrochemcal data indicate that [VIVO(HL)] form dimeric species in a weakly Lewis basic solvent by coodination of the alcohol group to the vanadium atom of the adjacent molecule.
  • Yuji Ando, Yukihiro Aoyama, Tomokazu Sasaki, Yasukazu Saito, Hiroaki H ...
    2004 Volume 77 Issue 10 Pages 1855-1859
    Published: 2004
    Released: October 09, 2004
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    A thermally regenerative fuel cell, converting low-quality heat at around 100 °C directly into electric power, is composed of a redox reaction pair of acetone hydrogenation and 2-propanol dehydrogenation. The magnitude of its open-circuit voltage (VOC) was determined by the Gibbs energy change of acetone hydrogenation, without exhibiting activation polarization. Its short-circuit current (ISC) was insensitive to the extents of catalyst loading at the anode, in contrast to the cathode, because acetone hydrogenation proceeded more slowly than hydrogen dissociation. The ISC characteristics were improved with increasing sulfuric acid concentrations at the cathode, which would have resulted from the rate enhancement of acetone reduction due to more abundant protons usable at the catalyst sites. Both VOC and ISC of the fuel cell were increased along with increasing the acetone/2-propanol ratio in the catholyte, suggesting favorable effects of the thermodynamical acetone activity and the coverage increment of acetone at the same cathode catalyst sites.
  • Yasuki Yoshimura
    2004 Volume 77 Issue 10 Pages 1861-1867
    Published: 2004
    Released: October 09, 2004
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    The free energy (ΔdisG°), enthalpy (ΔdisH°), and entropy of dissolution (ΔdisS°) for tris(amino acidato)cobalt(III) were estimated from the temperature dependence of the solubilities in water, aqueous Bu4NBr solutions, and ethanol. For mer-tris(β-alaninato)cobalt(III) (mer-[Co(β-ala)3]), mer-(+)-tris(L-threoninato)cobalt(III) (mer-(+)-[Co(L-thr)3]), and fac-(−)-tris(L-prolinato)cobalt(III) (fac-(−)-[Co(L-pro)3]), ΔtrH° and ΔtrS° of the transfer process from water to Bu4NBr solutions indicate that these chelates have rather a hydrophilic character. In addition to these chelates, for mer-(−)-tris(L-alaninato)cobalt(III) (mer-(−)-[Co(L-ala)3]), mer-(−)- and fac-(−)-tris(L-valinato)cobalt(III) (mer-(−)- and fac-(−)-[Co(L-val)3]), mer-(+)-tris(L-leucinato)cobalt(III) (mer-(+)-[Co(L-leu)3]), and so on, the dissolution behavior in ethanol was compared with that in water by using ΔdisG°, ΔdisH°, and ΔdisS° in both solvents. The dissolution behavior of these chelates may be divided into two groups, that is, a group composed of hydrophilic chelates and another group composed of hydrophobic chelates. In the former, the solubilities in water are larger than those in ethanol owing to both smaller ΔdisH° and larger ΔdisS° in water. In the latter, the solubilities in ethanol are larger than those in water owing to larger ΔdisS° in ethanol.
  • Takayoshi Suzuki
    2004 Volume 77 Issue 10 Pages 1869-1876
    Published: 2004
    Released: October 09, 2004
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    The complex chloride, Pd(Ph2Pqn)2Cl2 (Ph2Pqn = 8-(diphenylphosphino)quinoline), crystallized either in yellow plates (1a: from CH2Cl2/Et2O) or in orange needles (1b: from MeOH/Et2O). The corresponding bromide, Pd(Ph2Pqn)2Br2, initially deposited as yellow block crystals (2a) from MeOH/Et2O, turned to orange prisms (2b) on standing in the mother liquor. The X-ray crystallographic analyses of 1a and 2a revealed that two Cl and Br anions, respectively, were located above and below the square-planar PdII coordination plane of cis(P)-[Pd(Ph2Pqn)2]2+. Although the distances of Pd···Cl (3.262(3) and 3.386(3) Å) and Pd···Br (3.432(2) and 3.505(2) Å) in 1a and 2a, respectively, were too long for a bonding interaction between PdII and X, weak PdII···X charge-transfer interactions seem to be responsible for the yellow colors of these crystals. In contrast, in 2b, the PdII formed an elongated square-pyramidal five-coordinate complex, [Pd(Ph2Pqn)2Br]+, with a somewhat long Pd–Br bond (3.0136(8) Å) at the apical position. The crystal structure of Pd(Ph2Pqn)2ClBF4 (4) revealed that the PdII center in 4 took an extremely distorted square-planar coordination geometry with the Pd–Cl bond of 2.375(2) Å, while one of the Ph2Pqn ligands coordinated through only P; cis(P)-[PdCl(Ph2Pqn-κP,N)(Ph2Pqn-κP)]BF4.
  • Yusuke Suga, Motohiro Nakano, Hatsue Tamura, Gen-etsu Matsubayashi
    2004 Volume 77 Issue 10 Pages 1877-1883
    Published: 2004
    Released: October 09, 2004
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    [NEt4][Pt(ppy)(C3S5)] (ppy = C-deprotonated 2-phenylpyridine(−); C3S52− = 4,5-disulfanyl-1,3-dithiole-2-thionate(2−)), [NEt4]-, [NBun4][Pt(ppy)(C8H4S8)] (C8H4S82− = 2-{(4,5-ethylenedithio)-1,3-dithiole-2-ylidene}-1,3-dithiole-4,5-dithiolate(2−)) and [NEt4][Pt(ppy)(C10–C6S8)] (C10–C6S82− = 2-{bis(decylthio)-1,3-dithiole-2-ylidene}-1,3-dithiole-4,5-dithiolate(2−)) were prepared. They showed an intense electronic absorption band due to an intramolecular mixed metal/dithiolate ligand-to-ppy ligand charge transfer transition, which is somewhat sensitive to the solvent. The complexes exhibited first oxidation potentials of −0.27 to +0.02 V (vs Ag/Ag+) due to the dithiolate ligand-centered oxidation. They were oxidized by TCNQ and iodine to afford [Pt(ppy)(L)] and [Pt(ppy)(L)](I1.0–4.2) (L = C3S52−, C8H4S82−, and C10–C6S82−). Electrical conductivities of the oxidized C8H4S8- and C10–C6S8-species measured for compacted pellets at room temperature were 6.2 × 10−6–7.8 × 10−3 S cm−1, while those of the oxidized C3S5-species were very low [(3.8–6.2) × 10−9 S cm−1]. The X-ray crystal structure of [NBun4][Pt(ppy)(C8H4S8)] was clarified.
Organic and Biological
Applied and Materials
  • Manabu Igawa, Shuji Nemoto
    2004 Volume 77 Issue 10 Pages 1939-1943
    Published: 2004
    Released: October 09, 2004
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    The pertraction of hydrophobic organic solutes across a hydrophobic membrane is a continuous separation process, which can be used as a substitute to active carbon. The permeabilities of hydrophobic organic solutes were examined in a two compartment cell partitioned by a hydrophobic membrane. The permeability was dominated by the hydrophobicity of the solute and the dissociation in the receiving phase. The permeability of the hydrophobic solutes increased with increasing pH of the receiving phase solution for the Teflon membrane filter Fluoropore. The preferential permeability of a hydrophobic solute was obtained, and the pertraction of a hydrophobic solute against its concentration gradient was also possible under a concentration gradient of hydroxide ion. Solute permeability changes were observed by coating the surface of Fluoropore to cover its pores with tetrafluoroethene–hexafluoropropene copolymer, FEP, and a highly selective permeability was obtained between phenol and 2-isopropyl-5-methylphenol (thymol) by suppressing the phenol permeability by coating the FEP membrane.
  • Bunshi Fugetsu, Shuya Satoh, Toshikazu Shiba, Taeko Mizutani, Yoshinob ...
    2004 Volume 77 Issue 10 Pages 1945-1950
    Published: 2004
    Released: October 09, 2004
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    Ba2+–alginate coated vesicles (Ba2+–ALG) containing highly dispersed carbon nanofibers (CNFs) were successfully produced for the first time using an encapsulation technique. These Ba2+–ALG/CNFs composite vesicles showed high capabilities in trapping DNA-interactive types of chemicals. For example, 10.0 mL of the vesicles took 0.43 μmol of ethidium ions up from contaminated water within 8 min. Biocompatibility experiments performed in vitro and in vivo provided promising results, suggesting potential applications in in-situ environmental remediation. Kilogram quantities of the Ba2+–ALG/CNFs composite vesicles can be produced within a few hours.
  • Tsukasa Hatano, Ah-Hyun Bae, Masayuki Takeuchi, Atsushi Ikeda, Seiji S ...
    2004 Volume 77 Issue 10 Pages 1951-1957
    Published: 2004
    Released: October 09, 2004
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    It was found that 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS), which is known to aggregate in a one-dimensional fashion in water, acts as a template for the electropolymerization of aniline on an ITO electrode. Examinations using cyclic voltammetry (CV) and UV–vis spectroscopy established that J-aggregated TPPS molecules are entrapped in the resultant poly(aniline). Scanning electron microscopy (SEM) observations established that poly(aniline) grows to a nanosized rod-like structure, reflecting the aggregation structure of TPPS. The chemical oxidative polymerization of aniline in the presence of TPPS also gave a poly(aniline) rod-like structure containing the TPPS J-aggregate. It was found that the J-aggregation mode in the poly(aniline)/TPPS composite disappears when the medium pH is shifted from acidic to basic, but is regenerated when the medium pH is shifted from basic to acidic. This interconversion could be visually recognized by changes in the color and the fluorescence intensity.
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