Electron transfer and proton-coupled electron transfer reactivity and self-exchange of synthetic [2Fe-2S] complexes: models for Rieske and mitoNEET clusters.

ABSTRACT: This report describes the thermochemistry, proton-coupled electron transfer (PCET) reactions and self-exchange rate constants for a set of bis-benzimidazolate-ligated [2Fe-2S] clusters. These clusters serve as a model for the chemistry of biological Rieske and mitoNEET clusters. PCET from [Fe2S2((Pr)bbim)((Pr)bbimH)](2-) (4) and [Fe2S2((Pr)bbim)((Pr)bbimH2)](1-) (5) to TEMPO occurs via concerted proton-electron transfer (CPET) mechanisms ((Pr)bbimH2 = 4,4-bis-(benzimidazol-2-yl)heptane). Intermolecular electron transfer (ET) self-exchange between [Fe2S2((Pr)bbim)2](2-) (1) and [Fe2S2((Pr)bbim)2](3-) (2) occurs with a rate constant of (1.20 ± 0.06) × 10(5) M(-1) s(-1) at 26 °C. A similar self-exchange rate constant is found for the related [2Fe-2S] cluster [Fe2S2(SArO)2](2-/3-), SArO(2-) =

SUBMITTER: Saouma CT 

PROVIDER: S-EPMC3993882 | biostudies-literature | 2014 Mar

REPOSITORIES: biostudies-literature