Axial-ligand substitution reactions of a head-to-head pivalamidato-bridged Pt(III) binuclear complex bearing equatorial bromide ligands: A mechanistic study

Takaaki Terada, Yu Kamezaki, Ryota Nakamura, Tomoaki Sugaya, Satoshi Iwatsuki, Koji Ishihara, Kazuko Matsumoto

    Research output: Contribution to journalArticle

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    Abstract

    Axial ligand-substitution reactions of head-to-head (HH) a binuclear pivalamidato-bridged platinum(III) complex bearing equatorial bromide ligands, [(H2O)(NH3)2Pt(μ-pivalamidato)2Pt(Br)2(OH2)]2+ (1), with chloride and bromide ions were thermodynamically and kinetically investigated in acidic aqueous solutions. Reactions of 1 with p-styrenesulfonate and 4-penten-1-ol were also kinetically investigated in order to clarify the reaction mechanisms involving olefins. In contrast to the reactions of the HH tetraammine pivalamidato-bridged platinum(III) binuclear complex, [(H2O)(NH3)2Pt(μ-pivalamidato)2Pt(NH3)2(OH2)]4+ (2′), all substitution processes on 1 involve single-step reactions. The effect of the equatorial halide ligands on the axial ligand substitution reactions of 1 is discussed in relation to 2′; the rate-determining first substitution of H2O by X at the Pt(Br2O2) site in 1 is followed by a fast second substitution of H2O by X at Pt(N4). In contrast, axial ligand substitution on 2′ by X proceeds in two consecutive steps. Reactions of 1 with p-styrenesulfonate or 4-penten-1-ol proceed in one step to form only mono-π complexes that are in rapid equilibrium with σ complexes, whereas reactions of 2′ with these olefins proceed in three consecutive steps via di-π complexes. These mechanistic differences are interpreted in terms of enhanced charge localization in the mono-π complexes of 1 ([PtII(NH3)2(μ-pivalamidato)2PtIV(Br)2(p-styrenesulfonate or 4-penten-1-ol)]2+).

    Original languageEnglish
    Pages (from-to)391-399
    Number of pages9
    JournalInorganica Chimica Acta
    Volume467
    DOIs
    Publication statusPublished - 2017 Oct 1

    Fingerprint

    Bearings (structural)
    Bromides
    bromides
    Substitution reactions
    Ligands
    substitutes
    ligands
    Alkenes
    Platinum
    Olefins
    alkenes
    platinum
    Chlorides
    Ions
    halides
    chlorides
    aqueous solutions

    Keywords

    • 4-Penten-1-ol
    • Binuclear complex
    • p-Styrenesulfonate
    • Pivalamidate
    • Platinum
    • Reaction mechanism

    ASJC Scopus subject areas

    • Physical and Theoretical Chemistry
    • Inorganic Chemistry
    • Materials Chemistry

    Cite this

    Axial-ligand substitution reactions of a head-to-head pivalamidato-bridged Pt(III) binuclear complex bearing equatorial bromide ligands : A mechanistic study. / Terada, Takaaki; Kamezaki, Yu; Nakamura, Ryota; Sugaya, Tomoaki; Iwatsuki, Satoshi; Ishihara, Koji; Matsumoto, Kazuko.

    In: Inorganica Chimica Acta, Vol. 467, 01.10.2017, p. 391-399.

    Research output: Contribution to journalArticle

    Terada, Takaaki ; Kamezaki, Yu ; Nakamura, Ryota ; Sugaya, Tomoaki ; Iwatsuki, Satoshi ; Ishihara, Koji ; Matsumoto, Kazuko. / Axial-ligand substitution reactions of a head-to-head pivalamidato-bridged Pt(III) binuclear complex bearing equatorial bromide ligands : A mechanistic study. In: Inorganica Chimica Acta. 2017 ; Vol. 467. pp. 391-399.
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    AU - Kamezaki, Yu

    AU - Nakamura, Ryota

    AU - Sugaya, Tomoaki

    AU - Iwatsuki, Satoshi

    AU - Ishihara, Koji

    AU - Matsumoto, Kazuko

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