Formation of ruthenium(II)-bis(phosphine) monoxide complexes from the bis(phosphine) precursors:: BINAP-monoxide (BINAPO) as a six-electron (P,O,η2-naphthyl) donor

Aerobic oxidation of one P atom in cis-RuCl2(P-P)(L-2) complexes (P-P = (R)-BINAP (2,2'-bis(diphenylphosphino)-1,1'-binaphthyl) or dppb (1,4-bis(diphenylphosphino)butane), L-2 = bipy (2,2'-bipyridine) or phen (1,10-phenanthroline)) generates species such as [RuCl-(BINAPO)(L-2)]PF6 and cis-RuCl2(dppbO)(L-2) containing the corresponding bis(phosphine) monoxide ligands [BINAPO = 2-(diphenylphosphinoyl)-2'-(diphenylphosphino)-1,1'-(binaphthyl), and dppbO = 1-(diphenylphosphinoyl)-4-(diphenylphosphino)butane]. A novel coordination mode of BINAPO, involving the P-III atom, the O atom, and an eta(2)-naphthyl interaction proximate to the oxidized P atom, is identified by X-ray crystallography.