Synthesis and interconversion of, and restricted rotation in, phenyl complexes of ruthenium(II)

Abstract

The preparation and characterization of a range of phenyl complexes of ruthenium(II) are reported. For many of the complexes there is a substantial barrier to rotation of the phenyl ligand about the metal–phenyl bond, and n.m.r. studies have shown how the rate of rotation is affected by changes in the ligands in the complexes. Reaction of complexes [Ru(CO)(C₆H₄X)Y(PPh₃)₂] with phosphorus or arsenic ligands L provides a convenient route to [Ru(CO)(C₆H₄X)YL₃][X = H, Y = Cl, L = P(OMe)₃, PMe₂Ph, PMePh₂, P(OMe)₂Ph, or AsMe₂Ph; X = H, Y = Br or I, L = P(OMe)₃; X = 4-MeO, 4-Cl, or 4-Me, Y = Cl, L = P(OMe)₃]: ³¹P and ¹³C n.m.r. studies have demonstrated the sequence of steps involved and the stereochemistry of the intermediates, showing the influence of the trans-labilizing and trans-directing effects of the phenyl ligand.