Structural and functional models related to the nickel hydrogenases

In this review a historic overview is given of the biomimetic models synthesised since the presence of nickel in hydrogenases was first reported in 1981. The crystal structure of the [NiFe] hydrogenase isolated from Desulvofibrio gigas unexpectedly revealed a heterodinuclear active site, including a nickel ion and an iron centre. This report in 1995 gave an impetus to the development of new structural models for these enzymes. This review is focussed on the synthesis, spectroscopic features, and reactivity of the complexes that have been designed and synthesised as model systems for [NiFe] hydrogenases, with special attention for the heterodimetallic complexes that have been reported in the past decade. The complexes are classified according to the various ligand types, including sulfur, oxygen, nitrogen, and phosphorus donor atoms.