Transition metal nitrosyl compounds. Part XIV<SUP>(1)</SUP>. The oxidation of carbon monoxide by nitric oxide using [M(NO)<SUB>2</SUB>(PPh<SUB>3</SUB>)<SUB>2</SUB>]<SUP>n+</SUP> (M=Fe, Ru or Os; n=0. M=Co, Rh or Ir; n=1)

Carbon monoxide reacts with the cationic dinitrosyls [M(NO)2(PPh3)2]+ (M = Rh, Ir) under ambient conditions to produce CO2, N2O and the tricarbonyl cations, (M(CO)3(PPh3)2]+. The cationic tricarbonyls are reconverted into the dinitrosyl reactants on treatment with NO atca. 80&#176;. The Ru(NO)2(PPh3)2 and Os(NO)2(PPh3)2 complexes react similarly with CO but under more vigorous conditions whereas the corresponding dinitrosyls of cobalt and iron do not undergo this reaction under similar conditions. A pentacoordinate dinitrosyl intermediate [M(NO)2(CO)(PPh3)2]n+ is proposed and a mechanism for the catalytic oxidation of CO by NO is presented. Studies of Pt(N2O2)PPh3)2 establish that a dinitrogcn dioxide intermediate, produced by the coupling of two nitrosyl ligands, is reasonable