An iridium(iii/iv/v) redox series featuring a terminal imido complex with triplet ground state.

The iridium(iii/iv/v) imido redox series [Ir(N t Bu){N(CHCHP t Bu ₂ ) ₂ }] ^0/+/2+ was synthesized and examined spectroscopically, magnetically, crystallographically and computationally. The monocationic iridium(iv) imide exhibits an electronic doublet ground state with considerable 'imidyl' character as a result of covalent Ir-N t Bu bonding. Reduction gives the neutral imide [Ir(N t Bu){N(CHCHP t Bu ₂ ) ₂ }] as the first example of an iridium complex with a triplet ground state. Its reactivity with respect to nitrene transfer to selected electrophiles (CO ₂ ) and nucleophiles (PMe ₃ ), respectively, is reported.