Online ISSN : 2186-2451
Print ISSN : 1344-3542
ISSN-L : 1344-3542
Volume 71 , Issue 4
Showing 1-11 articles out of 11 articles from the selected issue
  • Osamu ENOKI, Takane IMAOKA, Kimihisa YAMAMOTO
    2003 Volume 71 Issue 4 Pages 254-256
    Published: April 05, 2003
    Released: August 30, 2019

    Electroreduction of carbon dioxide was homogeneously carried out using cofacial dinuclear metalloporphyrin CoTMPyP-MTPPS. The reduction was catalyzed by Co(I)TMPyP which generated at −1.8 V vs. Ag/Ag+. More excellent catalytic activity was observed in the presence of H2O in comparison with that for mononuclear one. The catalytic activity depended on the central metal of TPPS because they worked as an electron mediator.

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  • Mitsutoshi OKANO, Koji WATANABE, Shin TOTSUKA
    2003 Volume 71 Issue 4 Pages 257-259
    Published: April 05, 2003
    Released: August 30, 2019

    New members of network σ-conjugated polymers, i.e., methyl-, butyl-, octyl-, and phenyl-substituted network polystannanes were synthesized for the first time by electrochemical reduction of methyl-, butyl-, octyl-, and phenyl-trichlorostannanes, respectively. These network polystannanes, as well as the network polysilanes and polygermanes reported by the authors previously, had absorption which extended over 600 nm. They reacted with water just like previously reported linear polystannanes, however, the decomposition rate seemed lower. Thermochromic behavior, similar to those of alkyl-terminated network polysilanes and polygermanes, was also observed.

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  • Sungmo MOON, Masatoshi SAKAIRI, Hideaki TAKAHASHI, Kiyotaka SHIMAMURA
    2003 Volume 71 Issue 4 Pages 260-265
    Published: April 05, 2003
    Released: August 30, 2019

    The present investigation examined how to prevent Ni-P deposition through imperfections in anodic oxide films on aluminum and Al5052 alloy during electroless-plating. Pure aluminum and Al5052 alloy specimens were anodized in a sulfuric acid solution to form porous oxide films, and then immersed in boiling water to seal the pores. Confocal scanning laser microscopy was applied to examine the effect of pore-sealing on the Ni-P electroless deposition through imperfections. There were Ni-P domes deposited on both pure aluminum and Al5052 alloy covered with anodic oxide films through the imperfections in the oxide film. The number of Ni-P domes increased with electroless plating time on both kinds of specimens, and this change was more remarkable on Al5052 alloy, due to imperfections originating from second phase particles in the alloy substrate. Sealing treatment effectively prevented Ni-P dome deposition on both types of specimens, due to healing of the imperfections in the oxide films. Longer anodizing before the sealing treatment prevented the Ni-P deposition completely on the Al5052 alloy specimen even after 15 h of electroless plating.

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  • Futoshi MATSUMOTO, Takeyoshi OKAJIMA, Shinji UESUGI, Nobuyuki KOURA, T ...
    2003 Volume 71 Issue 4 Pages 266-273
    Published: April 05, 2003
    Released: August 30, 2019

    Electrogeneration of superoxide ion (O2) via one-electron reduction of dioxygen (O2) in aqueous solution has been examined with various thiol-modified Au electrodes. Based on the reactions between O2 and superoxide dismutase (SOD) or ferric cytochrome c (cyt.c (Fe3+)), thiols (thiol compounds) such as n-hexadecanethiol, n-decanethiol, mercaptoacetic acid and 3-mercaptopropionic acid were found to be new electrode modifiers which allow the electrogeneration of O2 on Au electrode. The current efficiencies for the electrogeneration of O2 at these thiol-modified Au electrodes were ca. 4%. Some probable mechanisms for the electrogeneration of O2 at the modified electrodes are discussed. It is concluded that, unlike quinoline compounds adsorbed on Hg electrode which are known to form liquid-like hydrophobic layers favorable for the electrogeneration of O2, the thiols adsorbing as self-assembled monolayers on the Au electrode surface do not necessarily form such hydrophobic layers, but prevent or reduce the spontaneous dismutation between O2 molecules adsorbing on the Au electrode surface by spatially separating them each other as a result of the adsorption of the thiol molecules themselves on it and consequently the electrogeneration of O2 can be realized at these thiol-modified Au electrodes.

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Q & A Electrochemistry and Electrochemical Measurement