Exploring the Electrochemistry of Iron Dithiolene and Its Potential for Electrochemical Homogeneous Carbon Dioxide...

In this work, the dithiolene complex iron(III) bis-maleonitriledithiolene [Fe(mnt)₂] is characterised and evaluated as a homogeneous CO₂ reduction catalyst. Electrochemically the Fe(mnt)₂ is reduced twice to the trianionic Fe(mnt)₂ ^3- state, which is correspondingly found to be active towards CO₂. Interestingly, the first reduction event appears to comprise overlapping reversible couples, attributed to the presence of both a dimeric and monomeric form of the dithiolene complex. In acetonitrile Fe(mnt)₂ demonstrates a catalytic response to CO₂ yielding typical two-electron reduction products: H₂, CO and CHOOH. The product distribution and yield were governed by the proton source. Operating with H₂O as the proton source gave only H₂ and CO as products, whereas using 2,2,2-trifluoroethanol gave 38 % CHOOH faradaic efficiency with H₂ and CO as minor products.