Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 79 , Issue 12
Showing 1-23 articles out of 23 articles from the selected issue
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The Chemical Society of Japan Award for Creative Work for 2004
  • Mitsuhiro Shibayama
    2006 Volume 79 Issue 12 Pages 1799-1819
    Published: 2006
    Released: December 13, 2006
    JOURNALS FREE ACCESS
    Concentration fluctuations in polymer gels are composed of dynamic thermal fluctuations and frozen inhomogeneities. Particularly, the latter is a characteristic of gels and is due to cross-linking. The frozen inhomogeneities manifest unique properties in polymer gels. Speckle patterns are commonly observed in gels. The time-correlation function of the scattering intensity entails a power-law behavior at the sol–gel transition. The appearance of speckle patterns is related to the nonergodicity of gels, and the power-law behavior corresponds to the self-similarity of clusters at the gelation threshold. In this review, it will be demonstrated that light scattering is one of the most powerful tools for structure characterization of polymer gels. Then, the universality and specificity of polymer gels will be examined for various types of gels, including physical gels, composite gels, and gelators.
  • Masahiro Yamashita, Shinya Takaishi
    2006 Volume 79 Issue 12 Pages 1820-1833
    Published: 2006
    Released: December 13, 2006
    JOURNALS FREE ACCESS
    This article describes the tuning of the electronic structures in a series of quasi-one-dimensional halogen-bridged Ni–Pd mixed-metal complexes, [Ni1−xPdx(chxn)2X]X2 (chxn = 1R,2R-diaminocyclohexane; X, Y = Cl or Br). In these compounds, planar [M(chxn)2] units are bridged by halogen ions (X), forming linear chain M–X–M structures. Therefore, their electronic structures are 1D and are composed of hybridization between the dz2 orbitals of the metal ions and pz orbitals of the bridging halogens. In this system, electron-correlation on the Ni sites and electron–phonon interaction on the Pd sites should compete with each other. Their electronic structures have been investigated by means of the single-crystal reflectance, ESR and IR spectroscopies, electrical conductivities, and X-ray diffuse scattering. Moreover, their local electronic structures have been directly observed by scanning tunneling microscopy (STM) using single-crystals at room temperature and under ambient pressure. As a result, while the oxidation state of the Ni sites is +3 in all mixing ratios in these compounds due to strong electron-correlation, the conversion from the PdIII Mott–Hubbard states to the PdII–PdIV mixed-valence states is observed around x ≈ 0.90 for Br and x ≈ 0.85 for Cl. Interestingly, the spin-soliton in Ni0.05Pd0.95(chxn)2Br3 was directly observed by STM for the first time.
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BCSJ Award Article
  • Manuel A. V. Ribeiro da Silva, Ana I. M. C. L. Ferreira, José R ...
    2006 Volume 79 Issue 12 Pages 1852-1859
    Published: 2006
    Released: December 13, 2006
    JOURNALS FREE ACCESS
    The standard (p° = 0.1 MPa) molar enthalpies of formation of 2-, 3-, and 4-bromoaniline, 2,4-, 2,5-, and 2,6-dibromoaniline, and 2,4,6-tribromoaniline were derived from the standard molar enthalpies of combustion, in oxygen, which yields CO2(g), N2(g), and HBr·600H2O(l), at T = 298.15 K, measured by using rotating-bomb calorimetry. The standard molar enthalpies of sublimation, or vaporization, of these compounds at T = 298.15 K were measured by using Calvet microcalorimetry, and so their standard molar enthalpies of formation in the gaseous state were derived. The enthalpies of fusion of the solid compounds were determined by DSC. The gas-phase enthalpies of formation were also estimated by density functional theory calculations performed at the BP86/6-31+G* level. As a result it is confirmed that thermodynamic data is consistent with intramolecular N–H···Br hydrogen bonding.
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