Nuclear magnetic resonance studies on metal complexes. Part II. Dimethylphenylphosphine complexes of iridium(III)

Abstract

Proton magnetic resonance spectral data are given for a series of iridium(III) complexes of type [IrX₂Y(PMe₂Ph)₃](X = Cl, Br, I, or H; Y = Cl, Br, I, H, CN, or SCN). Data for [IrH₃(PMe₂Ph)₃] and [NMe₄][IrCl₄(PMe₂Ph)₂] are also given. The methyl resonances determine the stereochemistry since two dimethylphenylphosphine ligands in mutual trans-positions usually show a 1 : 2 : 1 triplet: with no plane of symmetry through a P–Ir bond, however, a distorted triplet or multiplet is obtained owing to the non-equivalence of the two methyl groups on the phosphine ligand. A dimethylphenylphosphine ligand without another dimethylphenylphosphine ligand in a trans-position shows a 1 : 1 doublet methyl resonance. Shielding constants for the effects on τ-values of replacing chlorine ligands by bromine or iodine, are calculated. Data for hydride resonances are also given.