β-Elimination-Immune PCcarbeneP Iridium Complexes via Double C–H Activation: Ligand–Metal Cooperation in Hydrogen Activation

The synthesis of two members of a new PCP pincer ligand family and their complexation with iridium has been developed. Double C–H activation results in a ligand anchored by a carbene donor; hydrogen reversibly adds to the (PC carbene P)IrCl complexes 3 R (R = i Pr, t Bu). Aryl, amido, and phenoxy derivatives are available from the chlorides via salt metathesis. These compounds add H 2 and eliminate H–X; the iridium compound is trapped as a PC alkyl P iridium polyhydride.