Diastereoselective Synthesis of Chiral Octahedral Iridium(III) Phosphano–Oxazoline Complexes

Abstract

Reaction of the dimer [Ir(μ-Cl)(η2-coe)2]2 (coe = cyclooctene) with chiral phosphano–oxazoline ligands (PN*) renders neutral mononuclear iridium(I) complexes of the formula [IrCl(η2-coe)(PN*)] (1, 2), which in turn are oxidized to the corresponding iridium(III) hydride species [IrCl2H(η2-coe)(PN*)] (3, 4) by treatment with aqueous HCl. The latter react with diphosphanes (PP) in the presence of NaSbF6 to afford cationic complexes of stoichiometry [IrClH(PN*)(PP)][SbF6] (5–16). The fluorophenyldiphosphane-containing compounds [IrClH(PN*)(dfppe)][SbF6] (15, 16) evolve to the corresponding Ir(I) species [Ir(PN*)(dfppe)][SbF6] (17, 18) by HCl loss. The new compounds have been fully characterized by analytical and spectroscopic means, including the molecular structure determination of [IrCl2H(η2-coe)(PNInd)] (3), [IrClH(PNInd)(dppen)][SbF6] (6a,b), [IrClH(PNInd)(dppp)][SbF6] (7a), [IrClH(PNiPr)(dppp)][SbF6] (13a), [IrClH(PNInd)(dfppe)][SbF6] (15), [Ir(PNInd)(dfppe)][SbF6] (17), and [Ir(PNiPr)(dfppe)][SbF6] (18)...