Bis– o –Benzosemiquinonato Cobalt(II) and Nickel(II) Complexes with Neutral N‐Heterocyclic Carbene Ligand: Synthesis, Structure and Magnetic Properties

N,N′‐bis(2,6‐dimethylphenyl)imidazol‐2‐ylidene (Me 2 PhIm) interacts easily with cobalt(III) and nickel(II) o ‐benzosemiquinonato complexes, (3,6‐SQ) 3 Co and (3,6‐SQ) 2 Ni, as a neutral donor ligand giving mixed‐ligand NHC bis‐ o ‐benzosemiquinonato cobalt(II) and nickel(II) complexes ‐ (3,6‐SQ) 2 Co(Me 2 PhIm) ( 1 ) and (3,6‐SQ) 2 Ni(Me 2 PhIm) ( 2 ) (3,6‐SQ is radical‐anion 3,6‐di‐ tert ‐butyl‐ o ‐benzosemiquinolate). Cobalt complex 1 has a square‐pyramidal geometry in crystal with NHC ligand in the apical site in accordance with single‐crystal X‐ray analysis. Accordingly to magnetic measurements, the strong antiferromagnetic exchange interaction between spins of o ‐benzosemiquinonato ligands was observed for these complexes.