Cobalt PNCNHC 'pincers': ligand dearomatisation, formation of dinuclear and N2 complexes and promotion of C-H activation

Studies of ligand dearomatisation in cobalt phosphino-picoline N-heterocyclic carbene (PNCNHC)-type pincers have revealed the formation of dinuclear cobalt complexes by either side-arm metalation or C-H activation at the NHC backbone; in the latter case, the product complex, featuring an 'anionic dicarbene', originated from a dearomatised Co-I-N-2 complex.