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

A flexible di(sulfonamidophosphine) ligand (1(H2), (Ph2PNS)-S-H(O)(2)(NPPh2)-P-H) was synthesized from commercially available sulfamide and chlorodiphenylphosphine. Coordination of this new bisMETAMORPhos 1(H2) with [Ir(Cp*)Cl(mu-Cl)](2) instantly led to the formation of the P,P-coordinated bimetallic complex 2 [Ir(Cp*)Cl(kappa(1)-P-1 kappa(1)-P-2-1(H2))Ir(Cp*)Cl]. Reaction of 2 using excess NaOAc led to the formation of nonsymmetric homodinuclear complex 3[Ir(Cp*)Cl(kappa(2)-P,O; kappa(3)-P,N,C; mu-1)Ir(Cp*)], which contains two distinctly different Ir-III 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 H-2 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.