Cyclometalated Iridium Complexes from Intramolecular C–H Activation of [IrCp*Cl{═C(OMe)CH═C(CH3)R}L] (R = CH3, Ph; L = PPh2Me, PMe3)

The (methoxy)alkenylcarbeneiridium complexes [IrCp*Cl{═C(OMe)CH═CR1R2}L]PF6 (R1 = CH3, R2 = CH3, Ph; R1 = Ph, R2= H; L = PPh2Me, PMe3) can undergo an intramolecular C–H activation of one of the substituents R of the alkenyl fragment to give new five-membered-ring cyclometalated iridium complexes. In this work it is shown that the arrangement of substituents in the alkenyl fragment determines the size of the ring in the iridacycle complexes. The iridacyclopenta-1,3-diene complexes [IrCp*{═C(OMe)CH═CRCH2}L]PF6 (L = PPh2Me, R = CH3 (2a), Ph (4a); L = PMe3, R = CH3 (2b), Ph (4b)) can be deprotonated to give the iridacyclopenta-2,4-diene complexes [IrCp*{C(OMe)═CHCR═CH}L] (L = PPh2Me, R = CH3 (6a), Ph (7a); L = PMe3, R = CH3 (6b), Ph (7b)).