Utilization of Non-Innocent Redox Ligands in [FeFe] Hydrogenase Modeling for Hydrogen Production

Biomimetic diiron complexes bearing redox non-innocent ligands are discussed in this review. The complexes are synthesized to model the active site of [FeFe] hydrogenase in order to elucidate the catalytic mechanism of H-2 evolution and design superior artificial catalysts. Employment of the redox active ligands serves an important factor to modulate electronic structure of the Fe-2 core as the similar functionality exerted by the [4Fe4S] cofactor within the H-cluster. Different types of redox active ligands are summarized. The influence of their ligation is observable in spectroscopy as well as cyclic voltammetry, and studied by theoretical calculation.