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

In this work, the dithiolene complex iron(III) bis-maleonitriledithiolene [Fe(mnt) 2 ] is characterised and evaluated as a homogeneous CO 2 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 CO 2 . 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 CO 2 yielding typical two-electron reduction products; H 2 , CO and CHOOH. The product distribution and yield were governed by the proton source. Operating with H 2 O as the proton source gave only H 2 and CO as products, whereas using 2,2,2-trifluoroethanol gave 38% CHOOH faradaic efficiency with H 2 and CO as minor products