Nickel-iron-sulfur complexes: approaching structural analogues of the active sites of NiFe-hydrogenase and carbon monoxide dehydrogenase/acetyl-CoA synthase

The NiFe-dinuclear complexes [{Fe(NS3)(CO)(2)-S,S'}NiCl(dppe)] 1, [{Fe(NS3)(CO)-S,S'}NiCl(dppe)](2), [{Fe(NS3)(NO)-S,S'}NiCl(dppe)] 3,[{Fe(NS3)(NO)-S,S'} Ni(CH3)(dppe)] 4, [Ni{Fe(NS3)(CO)-S,S'}(2)] 5 have been prepared using the anions [Fe(NS3)(CO)](-) and [Fe(NS3)(NO)](-) (NS3 = N(CH2CH2S)(3)(3-)) as chelate ligands to nickel. Crystal structure characterisation has been carried out on 1, 3 and 5. The spectroscopic properties of the complexes have been measured. Complex 1 is a good structural analogue of the active form of the active site of NiFe-hydrogenase. Complexes 1-5 also show features related to the active sites of the nickel enzymes carbon monoxide dehydrogenase and acetyl-CoA synthase.