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

Abstract

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)₃³⁻) 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.