LAUSR

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 [(LN2S2)CoII(CO)FeIICp]+ complex (CoIIFeII, LN2S2 2- = 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(1,1'-diphenylethanethiolate), Cp- = cyclopentadienyl anion) can be (electro)chemically reduced to its CoIFeII form, and both complexes have been isolated and fully characterized by means of classic spectroscopic techniques and theoretical calculations. The redox properties of CoIIFeII 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.