Nuclear magnetic resonance studies on metal complexes. Part V. Dimethylphenylphosphine and dimethylphenylarsine complexes of rhodium(III)

Abstract

Rhodium trichloride and dimethylphenylphosphine react together in aqueous ethanol to give mer-[RhCl₃(PMe₂Ph)₃], fac-[RhCl₃(PMe₂Ph)₃], and the salt [PHMe₂Ph][RhCl₄(PMe₂Ph)₂]. Metathetical replacement reactions on mer-[RhCl₃(PMe₂Ph)₃] under mild conditions give complexes of the type [RhCl₂Y(PMe₂Ph)₃] configuration (IV; Y = Br, I, NCO, NCS, NO₂, or N₃) but under more vigorous conditions complexes of the type mer-[RhY₃(PMe₂Ph)₃](Y = Br, I, NCO, NCS, or N₃) are formed. The monothiocyanato-complex is N-bonded but on heating it gives the S-bonded linkage isomer. Methyl resonance data are given and are useful in assigning stereochemistry. The effects of ligands on methyl-resonance τ-values are discussed. Far-infrared data are given and rhodium–chlorine stretching frequencies assigned and discussed; they are useful in confirming the assigned stereochemistries.