Terminal cobalt(III) imido complexes supported by tris(carbene) ligands: imido insertion into the cobalt-carbene bond.

Highly reactive tris-carbene Co(I) complexes [(TIMENaryl)Co]Cl react with organic azides to yield monomeric Co(III) imido complexes [(TIMENaryl)Co(NAr')](BPh4) (aryl = mes, xyl; Ar = -C6H4-CH3, -C6H4-OCH3). The cobalt-imido fragment in these complexes is electrophilic and, as a result, the imido group readily inserts into the cobalt-carbene bond, yielding bis-carbene imine cobalt complexes.