[FeFe] hydrogenase active site modeling: a key intermediate bearing a thiolate proton and Fe hydride

The first di-protonated [FeFe] hydrogenase model relevant to key intermediates in catalytic hydrogen production is reported. The complex bearing the S-proton and Fe-hydride is structurally and spectroscopically characterized as well as studied by DFT calculations. The results show that the thiolate sulfur can accept protons during the catalytic routes.