Synthesis and characterisation of Mo^IV-oxo dithiolenes: formate dehydrogenase active site mimetics

The active sites of metalloenzymes continue to inspire synthetic chemists to create structural models of the intricate structures seen in biology. As well as the fundamental intellectual challenge, this is driven by the potential societal impact that many of these systems offer. Formate dehydrogenases (FDHs) hold such potential: formate is one of the key candidates as a hydrogen carrier for future energy transport. Efforts at mimicking the active site of FDH require the synthesis of (functionalised) molybdenum bis(dithiolene) complexes, principally featuring the Mo═O unit. In this review, we give an overview of the synthetic routes used to date in these efforts, along with key infrared and electrochemical data for the full collection of synthetic complexes reported to date.