Iron(II) and iron(III) complexes containing ethynyl thiophene fragments

A series of iron complexes of general formula Cp*(dppe)FeCC2,5-C4H2S-RSiMe3, has been synthesized. The thermally stable relative organoiron(III) complexes have also been prepared and characterized. Despite the presence of a ligand containing an extended π-electron system with up to fourteen sp or sp2 hybridized carbon atoms bound to the 17-electron d5 iron centre, these complexes can be regarded as metal centred radicals.