Reduction Reaction of the Copper(II) Complex Bearing 1,3-Di(pyridine-2-carboxaldimino)propane (pitn) by Decamethylferrocene in Acetonitrile

Atsutoshi Yamada, Yuki Watanabe, Kyoko Noda, Sumitaka Itoh, Koji Ishihara, Masahiko Inamo, Refat Moustafa Hassan, Hideo D. Takagi

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    Abstract

    The reduction reaction of the Cu(II)-pitn complex (pitn = 1,3-di(pyridine-2-carboxaldimino)propane) by decamethylferrocene [Fe(Cp*)2] was examined in acetonitrile. The observed pseudo-first-order rate constants exhibited saturation kinetics with increasing excess amount of [Fe(Cp*)2]. Detailed analyses revealed that the reaction is controlled by a structural change prior to the electron transfer step, rather than a conventional bimolecular electron transfer process preceded by ion pair (encounter complex) formation. The rate constant for the structural change was estimated to be 275 ± 13 s-1 at 298 K ({increment}H* = 33.3 ± 1.0 kJ·mol-1, {increment}S* = 86 ± 5 J·mol-1·K-1), which is the fastest among gated reactions involving CuN4 complexes. It was confirmed by EPR measurement and Conflex calculations that the dihedral angle between the two N-N planes is significantly large (40°) in solution whereas it is merely 17.14° in the crystal.

    Original languageEnglish
    JournalJournal of Solution Chemistry
    DOIs
    Publication statusAccepted/In press - 2014 Apr 5

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    Keywords

    • Acetonitrile
    • Cu(II)(pitn)
    • Cyclic voltammetry
    • Decemethylferrocene
    • Rate constants

    ASJC Scopus subject areas

    • Molecular Biology
    • Biophysics
    • Biochemistry
    • Physical and Theoretical Chemistry

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