Seven-coordinate dioxygen complexes from dioxygen addition to five-coordinate σ-phenyl, isocyanide-containing derivatives of ruthenium(II) and osmium(II). Crystal structures of Os(η2-O2)(η2-CPh=Np-chlorophenyl)Cl(PPh3)2 and Os(η2-SO4)(η2-CPh=Np-chlorophenyl)Cl(PPh3)2

Article abstract of DOI:10.1016/0022-328X(95)05920-K

Reaction of the hydrido complexes MHCl(CNR)(PPh₃)₃ (1a, M = Ru, R = p-tolyl; 1b, M = Os, R = p-tolyl; 1c, M = Os, R = p-chlorophenyl) with HgPh₂ results in formation of the five-coordinate σ-phenyl complexes MPhCl(CNR)(PPh₃)₂ (2a, M = Ru, R = p-tolyl; 2b, M = Os; R = p-tolyl; 2c, M = Os, R = p-chlorophenyl). These five-coordinate complexes, upon contact with dioxygen, form seven-coordinate dioxygen complexes M(η²-O₂)(η²-CPh=NR)Cl(PPh₃)₂ (3a, M = Ru, R = p-tolyl; 3b, M = Os, R = p-tolyl; 3c, M = Os, R = p-chlorophenyl) in which the phenyl group has migrated onto the isocyanide ligand to form a dihapto-iminoacyl ligand. The crystal structure of 3c has been determined. The complex 3c reacts with SO₂ to form the sulphate derivative Os(η²-SO₄)(η²-CPh=Np-chlorophenyl)Cl(PPh₃)₂ (4c), the crystal structure of which has also been determined. Sodium acetate reacts with 2a and 2b to form MPh(η²-O₂CCH₃)(CN p-tolyl)(PPh₃)₂ (5a, M = Ru; 5b, M = Os). CO reacts with OsPhCl(CN p-tolyl)(PPh₃)₂ to form OsPhCl(CO)(CN p-tolyl)(PPh₃)₂ (6b) and with CN p-tolyl to give OsPhCl(CN p-tolyl)₂(PPh₃)₂ (7b). Reaction of 2a with CO, and migration of the phenyl group, results in formation of the dihapto-iminoacyl complex Ru(η²-CPh=N p-tolyl)Cl(CO)(PPh₃)₂ (8a). Treatment of 2a with CN p-tolyl, followed by addition of HCl, gives the carbene complex RuCl₂(CPhNH p-tolyl)(CN p-tolyl)(PPh₃)₂ (9a). The hydrido complexes 1a-1c, which are the immediate precursors of the five-coordinate σ-phenyl isocyanide complexes, are generated by reaction of the dihydrido complexes MH₂(CNR)(PPh₃)₃ (10a, M = Ru, R = p-tolyl; 10b, M = Os, R = p-tolyl; 10c, M = Os, R = p-chlorophenyl) with HCl.