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

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) (<b>1</b>) or adt^Bn ({SCH₂}₂NBn = azadithiolate) (<b>2</b>). A crystallographic study was carried out on <b>2</b> and Mössbauer spectroscopy, and DFT calculations have been used to describe the electronic and structural properties of <b>1</b>. The electrochemical properties of <b>1</b> in the absence and in the presence of a weak acid have been the subject of a preliminary investigation