Reversible isomerization of a novel [FeFe]-hydrogenase model complex and water-promoted electrocatalytic proton reduction

摘要

mu-(SCH(CH2CH3)CH2S)-Fe-2(CO)(4)(kappa(2)-DPPE) (complex 1, DPPE is 1,2-bis (diphenylphosphor) ethane), which can be regarded as a model of the [FeFe]-hydrogenase active site, was synthesized and characterized. The reversible isomerization of complex 1 under N-2 and CO atmosphere was demonstrated by cyclic voltammetry, IR spectroscopy and P-31 NMR. Furthermore, we discovered that both the presence of a CO atmosphere and the addition of H2O can independently trigger the same inversion of configuration of complex 1. The electrocatalytic proton reduction capacity of 1 was evaluated under varying conditions. It was found that addition of a little H2O to CH3CN can facilitate its efficiency of electrocatalytic proton reduction. The possible mechanism of transition between axial/basal and dibasal isomers and the function of H2O in the electrocatalytic reaction are discussed.