Mixed-valence [FeIFeII] hydrogenase active site model complexes stabilized by a bidentate carborane bis-phosphine ligand†
Abstract
A series of [FeFe]-hydrogenase active site analogues, with the general formula [Fe2(dt)(CO)4(BC)] 1–3 (dt = dithiolate, pdt = propyl-1,3-dt (1), bdt = benzene-1,2-dt (2), edt = ethyl-1,2-dt (3); BC = 1,2-bisdiphenylphosphine-1,2-o-carborane), has been prepared and structurally characterized. While the electrochemical reductions of 1–3 are largely invariant to the different nature of their dt bridges, the oxidations differ by more than 120 mV in between the series. Remarkably, all three compounds are reversibly oxidized, with complex 1 that contains the most electron-donating pdt