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

CO-Bridged H-Cluster Intermediates in the Catalytic Mechanism of [FeFe]-Hydrogenase CaI

“…Thus, determining the nature of H-cluster redox states within this [FeFe] H 2 ase structural diversity can lead to new insights, and help refine state assignments. In addition, H-cluster synthetic analogs lack the catalytic performance of [FeFe] H 2 ases, suggesting the protein structure itself has a critical function in fine-tuning of the electron and proton-transfer steps. − …”

Insights into the Two‐Electron Reductive Process of [FeFe]H2ase Biomimetics: Cyclic Voltammetry and DFT Investigation on Chelate Control of Redox Properties of [Fe2(CO)4(κ2‐Chelate)(μ‐Dithiolate)]

“…[6] Changes in the electronic coupling betweenthe cubane and the diiron subsite are important in the control of the catalytic activity of H-cluster.C omplexes containing ligandsw ith redox properties have been synthesized for modelling the role of electron-reservoir played by the cubane [Fe 4 S 4 ]b ut non-innocence of the redox-ligand towards the diiron site was rarely observed or demonstrated in such systems. [7] The combination of such ligandsw ith carbonyl diiron systems can be achieved either by replacing terminal CO ligands or byf unctionalization of the dithiolate bridge. The complex [Fe 2 (CO) 3 (FcP*)(k 2 -dppv)(m-adt Bn )] (FcP* = [Fe(h 5 -C 5 Me 5 )(h 5 -C 5 Me 4 CH 2 PEt 2 )],d ppv = bis(diphenylphosphinoethylene), Bn = benzyl, adt = azadithiolate) (Scheme 1b)i sar epresentative and rare example of ad iiron system featuring a redox-active ligand (FcP*) in which an efficient electronic communication is proposed upon activation of H 2 ,t hus mimicking the functioning of the enzyme.…”

“…Changes in the electronic coupling between the cubane and the diiron subsite are important in the control of the catalytic activity of H‐cluster. Complexes containing ligands with redox properties have been synthesized for modelling the role of electron‐reservoir played by the cubane [Fe 4 S 4 ] but non‐innocence of the redox‐ligand towards the diiron site was rarely observed or demonstrated in such systems [7] . The combination of such ligands with carbonyl diiron systems can be achieved either by replacing terminal CO ligands or by functionalization of the dithiolate bridge.…”

Spectroscopic and theoretical investigation of the [Fe2(bdt)(CO)6] hydrogenase mimic and some catalyst intermediates

“…Together with a relatively mild over-potential (B500 mV), a reversible and stable reduction process makes [1] an interesting hydrogenase mimic system. 11,12 This complex is well established in the field of bio-inorganic chemistry 13,14 and modifications have also been performed by the group of Rauchfuss 15 and Kaur. 16 The proton reduction process utilizing [Fe 2 (bdt)(CO) 6 ] has previously been theoretically modelled and monitored by spectroelectrochemical methods and from these results a variety of (catalytic) mechanisms have been proposed.…”