A Dinuclear Cobalt(II) Complex with a Macrocyclic NHC‐Phenolate Ligand: Synthesis and Catalytic Oxygen Reduction Reactivity

In this work, the synthesis and structural characterization of a macrocyclic poly‐NHC pro‐ligand, H 6 ‐cimp(PF 6 ) 4 , is reported featuring methylene‐bridged imidazolium and p ‐methylphenol‐moieties. Using this ligand, a dinuclear cobalt complex, [Co II 2 (cimp)(CH 3 CN) 2 ](PF 6 ) 2 , is prepared, which is fully characterized by electrospray ionization mass spectrometry, elemental analysis, and single‐crystal X‐ray diffraction. Remarkably, this complex exhibited high catalytic activity for the four‐electron reduction of O 2 , achieving 88% selectivity in the presence of trifluoroacetic acid as proton donor and decamethylferrocene (Cp* 2 Fe) as electron donor.