[NiFe] dithiolene diphosphine complex for hydrogen gas activation: a Theoretic Insight

A diphosphino-nickel-iron dithiolene complex, [Ni(bdt)(dppf)] (bdt = 1,2-benzenedithiolate, dppf = 1,1-bis(diphenylphosphino)ferrocene), has been recently found to be reasonably active on proton reduction to dihydrogen (J. Am. Chem. Soc. 2015, 137, 1109). Interestingly, this exceptional complex was found to be also reactive towards dihydrogen activation as indicated by the electrochemical investigation. However, a pure nickel dithiolene diphosphine theoretical mode, excluding the contributions from iron moiety, was applied to attribute the experimental catalytic observation. We have re-visited the theoretical approach in details for this [NiFe] catalyst and compared it with the non-active nickel dithiolene diphosphine complexes. We found that both nickel and iron moieties in this newly developed complex were imperative for the observed catalytic per-formance, particularly towards the activation of dihydrogen.