Oxidation reaction of [Ni(1,4,7-triazacyclononane)2] 2+ by [Fe(o-phenanthroline)3]3+ in aqueous acidic solution at elevated pressures: Determination of the activation and reaction volumes for the Ni(III)/(II) couple

Sumitaka Itoh, Nobuyoshi Koshino, Masumi Katsuki, Toshiaki Noda, Koji Ishihara, Masahiko Inamo, Hideo D. Takagi

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    The reaction volume corresponding to the self-exchange process of the [Ni(tacn)2]3+/2+ couple was determined in aqueous acidic solution. Theoretical equations on the basis of the Mean Spherical Approximation were proposed for the estimation of reaction volumes for M n+1(n - 1)+ couples in solution, and the calculated reaction volumes were compared with the experimentally estimated values. The activation volume for the [Ni(tacn)2]3+/2+ couple was determined in the acidic condition from the cross reaction of [Ni(tacn)2]2+ and [Fe(o-phen)3]3+ at elevated pressures. The agreement of the experimentally estimated activation volume for the [Ni(tacn) 2]3+/2+ couple, -8.2 ± 2.4 cm3 mol -1, with the theoretically calculated value, -7.5 cm3 mol-1, within the allowed uncertainty (±1 cm3 mol-1) indicates that the electron self-exchange reaction of this redox couple obeys the Marcusian behavior in aqueous acidic solution.

    Original languageEnglish
    Pages (from-to)1862-1866
    Number of pages5
    JournalDalton Transactions
    Issue number12
    Publication statusPublished - 2004 Jun 21


    ASJC Scopus subject areas

    • Chemistry(all)

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