Hydroxymethylpyridine containing half-sandwich complexes of Rh(iii), Ir(iii) or Ru(ii)

Complexes of the formula [(ηn-ring)M(NOH){(R)-P1}][SbF6]2 ((ηn-ring)M = (η5-C5Me5)Rh, (η5-C5Me5)Ir, (η6-p-MeC6H4iPr)Ru; NOH = hydroxymethylpyridine ligand; {(R)-P1} = (R)-monophos) have been prepared from the corresponding dimers [{(ηn-ring)MCl}2(μ-Cl)2] through routes involving [(η5-C5Me5)RhCl2{(R)-P1}] or [(ηn-ring)MCl(NOH)][SbF6] intermediates. The new complexes have been characterized by analytical and spectroscopic means, including the determination of the crystal structures of [(η5-C5Me5)IrCl2{(R)-P1}] (1b), [(η6-p-MeC6H4iPr)RuCl(NOH-1)][SbF6] (2c), [(η5-C5Me5)IrCl{(R)-NOH-2}][SbF6] ((R)-3b), [(η5-C5Me5)Rh(NOH-1){(R)-P1}][SbF6]2 (4a) and [(η6-p-MeC6H4iPr)Ru{(R)-NOH-2}{(S)-P1}][SbF6]2 ((R)-5c′) by X-ray diffractometric methods. From NMR and X-ray data, the absolute configuration of the new chiral compounds was established.