A bio-inspired heterodinuclear hydrogenase CoFe complex

Abstract

Herein, a new heterobimetallic CoFe complex is reported with the aim of comparing its performance in terms of H₂ production within a series of related MFe complexes (M = Ni, Fe). The fully oxidized [(L^N2S2)Co^II(CO)Fe^IICp]⁺ complex (Co^IIFe^II, L^{N2S2 2−} = 2,2′-(2,2′-bipyridine-6,6′-diyl)bis(1,1′-diphenylethanethiolate), Cp⁻ = cyclopentadienyl anion) can be (electro)chemically reduced to its Co^IFe^II form, and both complexes have been isolated and fully characterized by means of classic spectroscopic techniques and theoretical calculations. The redox properties of Co^IIFe^II have been investigated in DMF, revealing that this complex is the easiest to reduce by one-electron among the analogous MFe complexes (M = Ni, Fe, Co). Nevertheless, it displays no electrocatalytic activity for H₂ production, contrary to the FeFe and NiFe analogs, which have proven remarkable performance.