Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
Volume 81 , Issue 8
Showing 1-16 articles out of 16 articles from the selected issue
Award Accounts
The Chemical Society of Japan Award for 2004
  • Masahiro Irie
    2008 Volume 81 Issue 8 Pages 917-926
    Published: August 15, 2008
    Released: August 11, 2008
    JOURNALS FREE ACCESS
    It is a dream for chemists to synthesize molecular systems, which can transform changes of molecular shape induced by external stimuli, such as chemicals, photons, and electrons (or holes), to macro-scale motion of the materials and perform mechanical work. To realize this dream we first prepared photoresponsive polyamides having azobenzene chromophores in the main chain. Although the polyamides changed conformation in solution upon photoinduced trans–cis isomerization, we failed to link the conformational change to macro-scale motion of polymer films and gels. During the course of study on photochromism of diarylethene single crystals we found that the surface morphology as well as the bulk shape of the single crystals reversibly changes upon photoisomerization of the component diarylethene molecules in the crystals. The photoinduced shape changes of the molecules in the densely packed crystals give rise to mechanical motion of the crystals and launch a tiny silica-particle. This is the first molecular system, which directly transforms changes of molecular shape to macro-scale motion of the materials and performs mechanical work. This account describes the progress of the research.
    Photoisomerization of diarylethene molecules in crystals induces surface morphology as well as shape changes of the crystals. The changes of molecular shape at the molecular level are successfully linked to macro-scale motion of the solid crystals. Fullsize Image
BCSJ Award Article
  • Kazuhiko Maeda, Hiroaki Terashima, Kentaro Kase, Masanobu Higashi, Mas ...
    2008 Volume 81 Issue 8 Pages 927-937
    Published: August 15, 2008
    Released: August 11, 2008
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    A composite material consisting of tantalum oxynitride (TaON) and monoclinic zirconium oxide (m-ZrO2) is prepared by a surface modification method as a photocatalyst with enhanced activity for H2 evolution from water under visible light (λ>420 nm). The composite is prepared by loading particulate Ta2O5 with nanoparticulate m-ZrO2 followed by nitridation at 1123 K for 15 h under NH3 flow. The activity of the m-ZrO2/TaON composite for H2 evolution from aqueous methanol solution is higher than that of either m-ZrO2 or TaON when loaded with nanoparticulate ruthenium as a H2 evolution site. The highest activity is obtained using a composite prepared with a Zr/Ta molar ratio of 0.1. The optimized material also provides elevated activity when used as an H2 evolution photocatalyst in Z-scheme overall water splitting in combination with Pt-loaded WO3 as an O2 evolution photocatalyst and an IO3/I shuttle redox mediator. The improvement in activity is attributed to the suppression of surface defect formation by inhibiting tantalum reduction during nitridation.
    A composite material consisting of TaON and monoclinic ZrO2 (m-ZrO2), which is prepared by nitridation of m-ZrO2/Ta2O5 composite, exhibits higher visible-light photocatalytic activity for H2 evolution than TaON. Fullsize Image
  • Yukio Nakano, Hiromi Ukeguchi, Takashi Ishiwata, Yugo Kanaya, Hiroto T ...
    2008 Volume 81 Issue 8 Pages 938-946
    Published: August 15, 2008
    Released: August 11, 2008
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    The rate constants of the reaction of NO3 with CH3I, which can affect iodine chemistry in the atmosphere, were measured in the temperature range of 298–323 K with cavity ring-down spectroscopy. The reaction has a rate constant of k=(4.1±0.2)×10−13 cm3 molecule−1 s−1 at 298 K. Uncertainties reported herein are one standard deviation. On the basis of an Arrhenius plot in the region of 298–323 K, the reaction has an activation energy (Ea=13±3 kJ mol−1). Density functional and coupled-cluster calculations suggest that the reaction proceeds via a transition state in which the hydrogen atom is nearly located at the middle position between the carbon atom of CH3I and the oxygen atom of NO3 to give HNO3+CH2I. On the atmospheric implications, box model simulations indicate that the present reaction has an important effect on the levels and diurnal patterns of the mixing ratios of NO3 and CH3I, and also on the activation of iodine chemistry in the atmosphere.
  • Yoshimasa Bando, Minoru Ashizawa, Tadashi Kawamoto, Takehiko Mori
    2008 Volume 81 Issue 8 Pages 947-955
    Published: August 15, 2008
    Released: August 11, 2008
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    Two new tetrathiapentalene (TTP)-based donor molecules have been synthesized, in which two of the four sulfur atoms of the inner TTP-skeleton of TMET-TTP (2-[4,5-bis(methylthio)-1,3-dithiol-2-ylidene]-5-(4,5-ethylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) are replaced by Se atoms. Four charge-transfer salts of these donors realize θ-type structures. One of the salts shows almost temperature-independent resistivity over a wide temperature range from 50 to 200 K. The calculated highest occupied molecular orbital (HOMO) is more populated on the non-Se-substituted side. This distribution is associated with the temperature-independent resistivity.
  • Bholanath Mandal
    2008 Volume 81 Issue 8 Pages 956-965
    Published: August 15, 2008
    Released: August 11, 2008
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    Three classes of pendent vertex- and pendant edge-weighted graphs of linear chains (class I), stars (class II), and cycles (class III) have been presented. These graphs (particularly class I and III) represent heteroconjugated π-systems. Sometimes such graphs appear as factored subgraphs of some complicated graphs. The eigenspectra of these graphs have been found out in analytical forms. These eigenspectra have been utilized i) to calculate the band (i.e., HOMO–LUMO) gaps of such graphs, ii) to find out three classes of inversely proportional graphs (with inversely proportional pairs of eigenvalues), and iii) to express eigenspectra of some complicated graphs in analytical forms along with some subspectral relationships. In the limit of n (number of vertices) to infinity, the band gap of the graph of class I has been shown to be the same with that calculated by considering its hypothetical “cyclic dimer.” Reciprocal graphs have also been considered in this context. These graphs are not all hypothetical. A few of them have also been synthesized.
  • Masashi Hatanaka, Ryuichi Shiba
    2008 Volume 81 Issue 8 Pages 966-978
    Published: August 15, 2008
    Released: August 11, 2008
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    Ferromagnetic interactions in three-dimensionally stacked organic-radical assemblies were deduced under periodic boundary conditions. Although the topological-linkage patterns apparently contained pentavalent carbon atomic sites due to the three dimensionalities, it was shown that the degenerate non-bonding crystal orbitals (NBCOs) were subject to orbital mixing to form Wannier-transformed NBCOs, analogous to non-Kekulé polymers. In the ferromagnetic π–π stacking modes, the NBCOs were spread over more than two adjacent unit cells. On the other hand, in the π–π antiferromagnetic stacking modes, the NBCOs were localized only at one unit cell. High-spin preferences in the ferromagnetic stacking modes were attributed to anti-parallel-spin instabilities in effective two-electron wave functions consisting of products of NBCOs (PNBCOs). Our analysis was confirmed by theoretical calculations.
  • M. R. Darafsheh, A. Moghani
    2008 Volume 81 Issue 8 Pages 979-982
    Published: August 15, 2008
    Released: August 11, 2008
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    The maturated and unmaturated groups were introduced by Shinsaku Fujita who used them in the markaracter table and the Q-conjugacy character table of a finite group. Then, he applied his results in this area of research to enumerate isomers of molecules. Using non-rigid group theory, it was shown that the full non-rigid (f-NRG) group of 1,3,5-trimethylbenzene (TMB) is isomorphic to wreath product of the cyclic group of order three and the symmetric group of order six on three letters (see Int. J. Quantum Chem. 2007, 107, 340). In this paper, we will show that this group has 13 dominant classes (similarly, Q-conjugacy characters) 9 of which are unmatured (similarly, Q-conjugacy characters such that they are the sum of two irreducible characters). Then Markaracter table and Q-conjugacy character table of the unmatured full non-rigid group TMB is derived.
  • Toshihiro Yamase, Eri Ishikawa
    2008 Volume 81 Issue 8 Pages 983-991
    Published: August 15, 2008
    Released: August 11, 2008
    JOURNALS OPEN ACCESS
    The long-term photolysis of [iPrNH3]6[Mo7O24]·3H2O in aqueous solutions at pH 5–6 is found to provide the formation of anti-tumoral [H2MoV12O28(OH)12(MoVIO3)4]6− species (1a), the core of which is a well-known ε-isomer ({ε-MoV12}) of the Keggin anion showing edge-shared MoVO6 octahedra in the arrangement of six diamagnetic MoV2-pairs with a MoV–MoV bond distance of 2.6 Å. To obtain structural insight of 1a in aqueous solutions from a viewpoint of the pharmaceutical mechanism, 95Mo NMR, electronic absorption, IR, and electrospray ionization mass (ESI-MS) spectrometries of 1a are investigated and indicate that the {ε-MoV12} core remains intact at pH 5–9 and that a detachment of the MoVIO3 unit from 1a proceeds at high pH level with an accompanying increase in the electronic transition of the MoV2 pairs. Highly positive and negative potentials (0.8–0.9 and −1.1– −1.2 V) of oxidation and reduction current peaks for the MoV2 pairs of 1a assist the structural stability of the ε-Keggin {MoV12} framework in aerobic solutions. A plausible mechanism of the photoreductive self-assembly of [MoVI7O24]6− to 1a through two- and four-electron reduction species, [MoV2Mo5O22(OH)2]6− ({MoV2MoVI5}) and [MoV4Mo3O20(OH)4]6− ({MoV4MoVI3}), is proposed in terms of the formation of a half molecule ([HMoV6O18(OH)6(MoVIO3)2]11−) of 1a, which is suggested by ESI-MS spectrometry of the photolytes.
  • Wataru Kosaka, Kazuhito Hashimoto, Shin-ichi Ohkoshi
    2008 Volume 81 Issue 8 Pages 992-994
    Published: August 15, 2008
    Released: August 11, 2008
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    A novel pyroelectric ferrimagnet, [{MnII(pyrazine)(H2O)2}{MnII(H2O)2}{NbIV(CN)8}]·4H2O, is synthesized. The crystal consists of an NbIV–CN–MnII linked three-dimensional network, which has an electric polarization along the b axis. This compound exhibits ferrimagnetism with a Curie temperature of 48 K due to the antiparallel ordering of magnetic spins on NbIV (S=1⁄2) and those on MnII (S=5⁄2).
  • Puttaiah Bhyrappa, Veerapandian Velkannan, Karuppaiah Karunanithi, Bab ...
    2008 Volume 81 Issue 8 Pages 995-1001
    Published: August 15, 2008
    Released: August 11, 2008
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    A series of meso-tetraarylporphyrins bearing electron-donor or electron-withdrawing substituents at the meso-phenyl groups were examined for antipodal β-pyrrole tetrabromination using different brominating agents. Porphyrins bearing electron-donor substituents undergo bromination at moderate temperatures with N-bromosuccinimide as the brominating agent while the electron-deficient porphyrins require liq. Br2 at room temperature. The brominated porphyrins were isolated in moderate to very good yields. Synthesized compounds were characterized by electronic absorption, 1H NMR, and mass spectroscopic methods. Regioselectivity of an electron-deficient porphyrin, 2,3,12,13-tetrabromo-5,10,15,20-tetrakis(4-methoxycarbonylphenyl)porphyrin was examined by single-crystal X-ray structure analysis and showed antipodal β-pyrrole bromo substitution.
  • Shuichi Haraguchi, Munenori Numata, Kenji Kaneko, Seiji Shinkai
    2008 Volume 81 Issue 8 Pages 1002-1006
    Published: August 15, 2008
    Released: August 11, 2008
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    It is known that an achiral water-soluble polythiophene (PT-1) is chirally twisted by complexation with a natural helix-forming polysaccharide, shizophyllan (SPG). We found that the chirality can be immobilized by sol–gel reaction of tetraethoxysilane (TEOS) with benzylamine as a catalyst (“solution mechanism”), where SPG acts not only as a chirality inducer for PT-1 but also as a chemical glue to adsorb silica particles onto the composite surface. When a complex with amine-appended SPG (SPG-NH) was used as a template, the sol–gel reaction proceeded according to the “surface mechanism,” where silica particles were formed mainly on the composite surface due to the catalytic effect of the covalently bound amino groups and thus the reaction conditions became milder. It was confirmed that under the “surface mechanism” the chemical and physical properties of the original PT-1/SPG-NH composite are maintained more efficiently.
  • Zhan-Xin Zhang, Dong-Qing Fei, Zhong-Jian Jia
    2008 Volume 81 Issue 8 Pages 1007-1011
    Published: August 15, 2008
    Released: August 11, 2008
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    Virgaurols A–D (14), four novel asymmetric eremophilane sesquiterpene dimers were isolated from the roots of Ligularia virgaurea. Especially, virgaurols A (1) and B (2) possessed novel carbon skeleton in which the two sesquiterpene units are uniquely connected by a single C–C bond directly. The structures of these dimers were determined on the basis of comprehensive spectral analysis. Compounds 1 and 3 were found to exhibit weak cytotoxicity against human leukemia (HL-60), human hepatoma (SMMC-7721), and human cervical carcinoma (HeLa) cells.
  • Rabbani M. Gulam, Masahiro Hamada, Ikuko Takamiya, Masahiko Shimoda, S ...
    2008 Volume 81 Issue 8 Pages 1012-1018
    Published: August 15, 2008
    Released: August 11, 2008
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    Chelated tethering ligands were confined on a Au(111) substrate, and the confinement of the ligands was confirmed by X-ray photoelectron spectroscopy (XPS). Palladium was anchored to the ligands to construct heterogeneous {Pd}–L–Au(111) catalysts (L = ligand). A {Pd}–Au(111) catalyst was also prepared by adsorbing the Pd complex directly on the Au(111) substrate without a tethering ligand. Both types of catalysts were used in the Mizoroki–Heck reaction to evaluate their catalytic activities. The tether-ligated Pd catalyst {Pd}–L–Au(111) activity decreased with recycling, whereas the {Pd}–Au(111) catalyst was quite stable upon reuse. The surfaces of both catalyst types were evaluated using XPS to determine the presence of tethering ligands and/or Pd on the Au(111). The ligands of the tether-ligated Pd catalysts could not be detected on the Au(111) surface after the Mizoroki–Heck reaction, which suggests weak bonding of the S–Au by which the ligand is bound to the Au(111) substrate.
  • Kenya Kobayashi, Takashi Nishikata, Yasunori Yamamoto, Norio Miyaura
    2008 Volume 81 Issue 8 Pages 1019-1025
    Published: August 15, 2008
    Released: August 11, 2008
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    Baeyer–Villiger oxidation of chiral β-diaryl ketones synthesized by 1,4-addition of arylboronic acids to β-aryl-α,β-unsaturated ketones catalyzed by a palladium(2+)–chiraphos complex provided optically active β-diaryl esters up to 98% ee. The protocol was applied to the synthesis of a potent competitive muscarinic receptor antagonist, (R)-tolterodine (21), which has a chiral center consisting of two aryl rings.
  • Toshiaki Teruya, Arihiro Iwasaki, Kiyotake Suenaga
    2008 Volume 81 Issue 8 Pages 1026-1027
    Published: August 15, 2008
    Released: August 11, 2008
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    A new bromotyrosine-derived metabolite, 20-N-methylpurpuramine E (1), was isolated from the marine sponge Pseudoceratina purpurea. The structure was elucidated by spectroscopic analysis. 20-N-Methylpurpuramine E (1) showed weak cytotoxicity against HeLa S3 cells.
  • Kana Mizukoshi, Shuji Okada, Tatsumi Kimura, Satoru Shimada, Hiro Mats ...
    2008 Volume 81 Issue 8 Pages 1028-1037
    Published: August 15, 2008
    Released: August 11, 2008
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    Three diacetylene monomer model compounds with similar π-conjugation systems, 10-phenyl-5,7,9-decatriynyl N-phenylcarbamate (1), (E)-10-phenyldec-9-en-5,7-diynyl N-phenylcarbamate (2), and (E)-10-phenyldec-5-en-7,9-diynyl N-phenylcarbamate (3), were synthesized and their properties and solid-state polymerization were investigated. Based on the absorption spectra of the monomers, it was found that the conjugation effect of a double bond was different from that of a triple bond in solution. Monomers 1, 2, and 3 gave one, two, and five crystal forms, respectively, of which 1 and one of the crystal forms of 2 (2a) could be polymerized in the solid state. The conversions after γ-ray irradiation (1 MGy dose) were 53% and 20%, respectively. The longest-wavelength absorption maxima of the polymers prepared from 1 and 2a were 645 and 655 nm, respectively. The polymerizable crystals 1 and 2a were found to have layered monomer structures with spacing of 3.1–3.6 nm. Based on solid-state 13C NMR spectra, the polymerization sites of 1 were determined to be the 1,4- and 3,6-positions with respect to the phenyl ring, and that of 2a was determined to be the 3,6-position with respect to the phenyl ring.
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