Electrocatalytic CO ₂ Reduction to Formate by a Highly Conjugated TriCobalt Phosphino‐Thiolate Complex

Modular synthetic modification to ligand scaffolds of metal complexes provides an approach to rational improvement of existing molecular catalytic systems. A previous report from the Marinescu group has shown that a cobalt phosphino thiolate complex ( [Co(triphos)(bdt)] + ) has excellent selectivity and activity for electrocatalytic CO 2 reduction to formate. Here, a multimetallic analogue, [Co 3 (triphos) 3 (tht)] 3+ , that is conjugated through a trinucleating dithiolene ligand in the form of triphenylene–2,3,6,7,10,11–hexathiolate is investigated. While voltammetric studies indicate enhanced current densities under similar conditions to [Co(triphos)(bdt)] + , electrolysis and ultraviolet–visible spectroscopy results suggest significant catalyst degradation and overall moderate faradaic yields.