Diiron Complexes with a [2Fe3S] Core Related to the Active Site of [FeFe]H2ases

Six-membered heterocycles, 1,4-dithiane and 1,4-thioxane, were treated with [Fe-2(CO)(6)(mu-pdt)] (pdt = propanedithiolate) in order to synthesise [2Fe3S] complexes with well positioned heteroatoms as potential base. Monosubstituted compounds of general formula [Fe-2(CO)(5)L(mu-pdt)] (L = 1,4-dithiane, 1,4-thioxane) were mainly obtained and characterised by H-1 NMR, IR, elemental analysis and X-ray diffraction studies. Electrochemical behaviour of these monosubstituted derivatives was investigated by cyclic voltammetry. An original tetranuclear cluster with a [4Fe8S] core was also isolated as a minor product and structurally characterised.