Synthesis and Reactivity of New Bis(N-heterocyclic carbene) Iridium(I) Complexes

New complexes of the type trans-[IrCl(η2- COE)(NHC)2] (COE = cis-cyclooctene; NHC = Nheterocyclic carbene) have been prepared in one step from the reaction of ca. 4 equiv of NHC or [AgCl(NHC)] with [IrCl(η2-COE)2]2 in benzene. These new complexes have been characterized by techniques including NMR and IR
spectroscopy, X-ray crystallography, and elemental analysis. Exposing trans-[IrCl(COE)(IiPrMe)2] to CO yielded trans-[IrCl(CO)(IiPrMe)2], which is the only bis(NHC) analogue of Vaska’s complex trans-[IrCl(CO)(PPh3)2] known to date. The
synthesis of trans-[Ir(CO)(IiPrMe)2(R)] (R = MeO, PhCC, OSiPh3, O2CPh) complexes has been achieved via deprotonation reactions involving the new hydroxide species trans-[Ir(OH)(CO)(IiPrMe)2].