Formation and Site-Selective Reactivity of a Nonsymmetric Dinuclear Iridium BisMETAMORPhos Complex

Abstract

A flexible di(sulfonamidophosphine) ligand (1H2, Ph2PNHS(O)2NHPPh2) was synthesized from commercially available sulfamide and chlorodiphenylphosphine. Coordination of this new bisMETAMORPhos 1H2 with [Ir(Cp*)Cl(μ-Cl)]2 instantly led to the formation of the P,P-coordinated bimetallic complex 2 [Ir(Cp*)Cl(κ1-P1; κ1-P2-1H2)Ir(Cp*)Cl]. Reaction of 2 using excess NaOAc led to the formation of nonsymmetric homodinuclear complex 3 [Ir(Cp*)Cl(κ2-P,O; κ3-P,N,C; μ-1)Ir(Cp*)], which contains two distinctly different IrIII centers, with a fac-P,N,C and a fac-P,O,Cl coordination environment. The ligand is overall trisanionic due to additional intramolecular C–H activation of a flanking phenyl ring. Complex 3 reacts selectively at the Ir(P,O,Cl) center with a single equivalent of HCl or H2 to generate complexes 4 and 5, respectively. These complexes are generated via heterolytic cleavage of the H–Cl or H–H bond, which reprotonates the ligand showing its bifunctional applicability. The Ir–C bond is found to be inert under these conditions.