[NiFe] hydrogenases: how close do structural and functional mimics approach the active site?

Abstract

Hydrogen is being considered as a versatile alternative fuel with the ever increasing energy demand and oil prices. Hydrogenases (H2ases) found in bacteria, archaea and eukaryotes are very efficient catalysts for biological hydrogen production. An important and unique hydrogenase enzyme is the [NiFe] H2ase, with an unusual heterobimetallic site. Since the determination of its crystal structure, a variety of complexes have been synthesised and studied. Bioinspired and biomimetic complexes have been investigated as potential catalysts. So far, of all the reported complexes only a few of them have been found to be catalytically active. Moreover, most of the reports are on the reverse reaction, e.g. proton reduction rather than dihydrogen oxidation. This perspective article therefore reviews the structural and functional aspects of the very recently reported model complexes that mimic the [NiFe] hydrogenase active site either in structure or function or both.

Experimental and DFT Investigations Reveal the Influence of the Outer Coordination Sphere on the Vibrational Spectra of Nickel-Substituted Rubredoxin, a Model Hydrogenase Enzyme

“…44,45 From an experimental standpoint, a similar argument can be made: Recreating an entire enzyme poses great biochemical difficulties, but generating a synthetic model that includes only the metal center and the primary coordination sphere typically fails to reproduce the reactivity of the enzyme. 26,95 It is clear that, on both fronts, an intermediate approach is necessary.…”

Hydrogen-activating models of hydrogenases

“…This article reviews the current state of biomimetic hydrogen activation. Although several reviews on hydrogenases and their models have been published [4][5][6][27][28][29][30][31], this topic has not been exclusively covered.…”

Molecular Electrocatalysts for the Hydrogen Evolution Reaction: Input from Quantum Chemistry

“…[4,[22][23][24] We presenth erein af ew differentm echanistic pathways that have been proposed over the past ten years. There has not been ac omplete consensus on the catalytic cycle of [NiFe]-hydrogenases.…”