7-COORDINATE DIOXYGEN COMPLEXES FROM DIOXYGEN ADDITION TO 5-COORDINATE SIGMA-PHENYL, ISOCYANIDE-CONTAINING DERIVATIVES OF RUTHENIUM(II) ANDOSMIUM(II) - CRYSTAL-STRUCTURES OF A(2)-O-2)(ETA(2)-CPH=NP-CHLOROPHENYL)CL(PPH(3))(2) AND A(2)-SO4)(ETA(2)-CPH=NP-CHLOROPHENYL)CL(PPH(3))(2)

Reaction of the hydride complexes MHCl(CNR)(PPh(3))(3) (1a, M = Ru, R= p-tolyl; 1b, M=Os, R=p-tolyl; 1c, M=Os, R=p-chlorophenyl) with HgPh(2) results in formation of the five-coordinate sigma-phenyl complexes MP hCl(CNR)(PPh(3))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(eta(2)-O-2)(eta( 2)-CPh=NR)Cl(PPh(3))(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 t he isocyanide ligand to form a dihapto-iminoacyl ligand. The crystal s tructure of 3c has been determined. The complex 3c reacts with SO2 to form the sulphate derivative Os(eta(2)-SO4)(eta(2)-CPh =Np-chloropheny l)Cl(PPh(3))(2) (4c), the crystal structure of which has also been det ermined. Sodium acetate reacts with 2a and 2b to form OsPhCl(CO)(CNp-t olyl)(PPh(3))(2) (6b) and with CNp-tolyl to give OsPhCl(CNp-tolyl)(2)( PPh(3))(2) (7b). Reaction of 2a with CO, and migration of the phenyl g roup, results in formation of the dihapto-iminoacyl complex Ru(eta(2) 2-CPh=Np-tolyl)Cl(CO)(PPh(3))(2) (8a). Treatment of 2a with CNp-tolyl, followed by addition of HCl, gives the carbene complex RuCl2(CPhNH p- tolyl)(CNp-tolyl)(PPh(3))(2) (9a). The hydride complexes 1a-1c, which are the immediate precursors of the five-coordinate sigma-phenyl isocy anide complexes, are generated by reaction of the dihydrido complexes MH(2)(CNR)(PPh(3))(3) (10a, M=Ru, R=p-tolyl; 10b, M=Os, R=p-tolyl; 10c , M = Os, R = p-chlorophenyl) with HCl.