Bulletin of the Chemical Society of Japan
Online ISSN : 1348-0634
Print ISSN : 0009-2673
ISSN-L : 0009-2673
81 巻 , 3 号
Award Accounts
The Chemical Society of Japan Award for Creative Work for 2006
  • Michio Murata, Nobuaki Matsumori, Keiichi Konoki, Tohru Oishi
    2008 年 81 巻 3 号 p. 307-319
    発行日: 2008/03/15
    公開日: 2008/03/13
    ジャーナル フリー
    Marine dinoflagellates are a rich source of structurally and biologically intriguing secondary metabolites. Among those, maitotoxin may be one of the best known examples, which is the largest natural product known to date and possesses the most potent toxicity known amongst non-proteinaceous compounds. Structural studies of maitotoxin are reviewed with a particular focus on the configuration and mode of action of this unique toxin. In addition, there are many marine natural products which bind to biomembranes to exert their biological activities. To gain a better understanding of their mode of action, conformation, and bimolecular interaction occurring in biomembranes are particularly important. Recent results from NMR studies of membrane systems in the authors’ group are reviewed briefly.
    Bioactivity-relevant conformation of potent marine natural products such as ladder-shaped polyether and polyhydroxy–polyene compounds is discussed. NMR-based methodologies to determine relative configuration and to elucidate active conformation are described briefly. Fullsize Image
The Chemical Society of Japan Award for Young Chemists for 2005
BCSJ Award Article
  • Tsuyoshi Murata, Gunzi Saito, Kazukuni Nishimura, Yuichiro Enomoto, Ge ...
    2008 年 81 巻 3 号 p. 331-344
    発行日: 2008/03/15
    公開日: 2008/03/13
    ジャーナル フリー
    Reaction between cytosine, a nucleobase, in methanol and several 7,7,8,8-tetracyanoquinodimethane derivatives (R-TCNQ) in acetonitrile yielded three kinds of ionic solids; (I) insulators composed of methoxy-substituted R-TCNQ anions, (II) semiconducting fully ionic R-TCNQ radical anion salts, and (III) conductive partially ionic or mixed-valent R-TCNQ radical anion salts. Electronic and chemical structures of these products were characterized by optical and magnetic measurements, and structural and elemental analyses. Cation units in all products were found to be protonated cytosine species. Crystal structures were determined for methoxy-substituted anion salts (R = F4 and H) in Group I and R-TCNQ radical anion salts (R = H and Et2) in Group II with hemiprotonated cytosine pairs formed by triple self-complementary hydrogen bonds. They established one-dimensional hemiprotonated cytosine ribbons by double complementary hydrogen bonds. Hydrogen bonds between cytosine and R-TCNQ anions exhibited high potential to regulate molecular arrangements producing a segregated layered structure and uniform arrangement of R-TCNQ radical anion columns stable down to low temperature. The partially ionic salt of MeTCNQ in Group III exhibited metallic behavior and the highest conductivity of 10+1 S cm−1 so far observed for charge-transfer complexes based on biological molecules.
    Charge-transfer complex formation between cytosine and R-TCNQ derivatives in MeOH yielded three kinds of ionic products; destructed R-TCNQ anion, fully ionic R-TCNQ radical anion, and mixed-valent and conductive R-TCNQ radical anion salts with hemiprotonated cytosine cations. Fullsize Image