Inorganic clusters with a [Fe₂MoOS₃] core - A functional model for acetylene reduction by nitrogenases

We report the first example of a wholly inorganic mimic of a part of the FeMoco active centre of nitrogenases. We detail the synthesis, characterisation and reactivity of two related, transient hydride-containing inorganic clusters, a dihydride complex and a vinyl monohydride complex, which bear the [Fe₂MoOS₃] portion of FeMoco. The dihydride complex is capable of reducing acetylene to ethylene via the vinyl monohydride complex. In the reaction cycle, a transient low-valent complex was generated by the reductive elimination of H₂ or ethylene from dihydride or vinyl monohydride complexes, respectively.