Tuning of electron transfer in diiron azo-bridged complexes relevant to hydrogenases

The possibility of using hydrogenase models based on Fe2(μ-NRN) complexes was investigated. The use of benzo-[c]-cinnoline (BC = N2C12H8) bridge allows for an unprecedented control of the electron-transfer process in diiron complexes. We were able to modify the potential gap between the two one-electron reduction steps of [Fe2(BC)(CO)6] by changing the solvent properties. The catalyst exhibits modest catalytic activity for proton reduction. However, there is a considerable opportunity for improvement considering the wide range of azo-bridged diiron described in the literature.