Formation of Ruthenium(II)−Bis(phosphine) Monoxide Complexes from the Bis(phosphine) Precursors: BINAP-Monoxide (BINAPO) as a Six-Electron (<i>P</i>,<i>O</i>,η²<i>-</i> Naphthyl) Donor

Aerobic oxidation of one P atom in cis-RuCl2(P−P)(L2) complexes (P−P = (R)-BINAP (2,2‘-bis(diphenylphosphino)-1,1‘-binaphthyl) or dppb (1,4-bis(diphenylphosphino)butane), L2 = bipy (2,2‘-bipyridine) or phen (1,10-phenanthroline)) generates species such as [RuCl(BINAPO)(L2)]PF6 and cis-RuCl2(dppbO)(L2) 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 PIII atom, the O atom, and an η2-naphthyl interaction proximate to the oxidized P atom, is identified by X-ray crystallography.