Dithiolato-bridged dinuclear iron-nickel complexes [Fe(CO)2(CN)2(mu-SCH2CH2CH2S)Ni(S2CNR2)]- modeling the active site of [NiFe] hydrogenase

NiFe] hydrogenase, the enzyme of which catalyzes the reversible oxidation of molecular hydrogen to protons and electrons, contains a unique heterodinuclear thiolate-bridged Ni-Fe complex in which the iron center is coordinated by CO and CN. We have synthesized dithiolate-bridged Ni-Fe complexes bearing CO and CN ligands to model the active center of NiFe] hydrogenase. The Ni-Fe complexes containing a (CN)2(CO)2Fe(mu-S2)NiS2] framework are the closest yet structural models of NiFe] hydrogenase.