New Systematic Route to Mixed-Valence Triiron Clusters Derived from Dinuclear Models of the Active Site of [Fe–Fe]-Hydrogenases

Abstract : A novel reaction pathway to synthesize the linear trinuclear clusters [Fe3(CO)5(κ2-diphosphine)(μ-dithiolate)2] via the direct reaction of the dinuclear hexacarbonyl precursor [Fe2(CO)6(μ-dithiolate)] with the mononuclear species [Fe(CO)2(κ2-diphosphine)(κ2-dithiolate)] has been developed with diphosphine (dppe) and dithiolate (pdt = propanedithiolate) (1) or adtBn ({SCH2}2NBn = azadithiolate) (2). A crystallographic study was carried out on 2 and Mössbauer spectroscopy, and DFT calculations have been used to describe the electronic and structural properties of 1. The electrochemical properties of 1 in the absence and in the presence of a weak acid have been the subject of a preliminary investigation.