Synthesis and Characterization of a Series of Model Complexes of the Active Site of [Fe]-Hydrogenase (Hmd)

A series of Fe complexes were synthesized and characterized as small molecule mimics for the active site of [Fe]-hydrogenase (Hmd). The collection includes both structurally new compounds and analogues of previously reported models. These complexes contain the essential ligands of the enzyme, namely, acyl, CO, pyridone, and sulfur ligands. They serve as IR and Mossbauer spectroscopic models for the Fe center in [Fe]-hydrogenase. The field-dependent Mossbauer study of representative model complexes shows that the sign and absolute value of the quadrupole splitting are sensitive to the change in the ligand environment of the Fe center.