Iridium abnormal N-heterocyclic carbene hydrides via highly selective C-H activation

Imidazoliums with proximal phosphines undergo C-H oxidative addition on [Ir(COD)Cl](2) to give iridium(III) abnormal carbene hydrides. The effects of the length of the linker between the imidazolium and the phosphine are systematically studied. These C-H activation products can undergo base-promoted H-Cl reductive elimination to afford the corresponding Ir(I) abnormal NHC complexes.