Orestes Rivada‐Wheelaghan

A pyrazole‐based ligand substituted with terpyridine groups at the 3 and 5 positions has been synthesized to form the dinuclear cobalt complex 1 , that electrocatalytically reduces carbon dioxide (CO 2 ) to carbon monoxide (CO) in the presence of Brønsted acids in DMF. Chemical, electrochemical and UV‐vis spectro‐electrochemical studies under inert atmosphere indicate pairwise reduction processes of complex 1 . Infrared spectro‐electrochemical studies under CO 2 and CO atmosphere are consistent with a reduced CO‐containing dicobalt complex which results from the electroreduction of CO 2 . In the presence of trifluoroethanol (TFE), electrocatalytic studies revealed single‐site mechanism with up to 94 % selectivity towards CO formation when 1.47 M TFE were present, at −1.35 V vs. Saturated Calomel Electrode in DMF (0.39 V overpotential). The low faradaic efficiencies obtained (<50 %) are attributed to the generation of CO‐containing species formed during the electrocatalytic process, which inhibit the reduction of CO 2 .