M(CO)6 (M=Cr, Mo, W) derivatives of (o-anisyl)diphenylphosphine, bis(o-anisyl)phenylphosphine tris(o-anisyl)phosphine and (p-anisyl)bis(o-anisyl)phosphine

Aromatic tertiary phosphine ligands having ortho-methoxy substituents reacted with Group 6 metal carbonyls to form complexes with monodentate bonding through the phosphorus atom. One tungsten hexacarbonyl derivative with two P-bonded phosphine ligands was also formed. The complexes were characterized by X-ray crystallography, 1H, 13C{1H} and 31P{1H) NMR spectroscopy, IR spectroscopy and elemental analysis. The steric properties of the ligands were studied by molecular modelling methods. Metal–phosphorus bond distances correlate with cone angles of the phosphines.