Conversion of Coordinated Carbon Monoxide into Carbon Dioxide via Oxygen-atom transfer from Coordinated Nitrite: Thermolysis of Ru(NO2)2(CO)2(PPh3)2

Article abstract of DOI:10.1021/ja00402a024

The thermolysis (111 deg C, toluene solution) of Ru(NO2)2(CO)2(PPh3)2 in the presence of excess PPh3 procced according to the stoichiometry Ru(NO2)2(CO)2(PPh3)2 + PPh3 -> Ru(NO2)2(PPh3)2 + CO2 + CO + Ph3PO.Two highly selective oxygen-atom transfer processes are involved in the overall thermolysis reaction: (i) Ru(NO2)2(CO)2(PPh3)2 -> Ru(ONO)(CO)(NO)(PPh3)2 + CO2; (ii) Ru(ONO)(CO)(NO)(PPh3)2 + PPh3 -> Ru(NO2)2(PPh3)2 + CO + Ph3PO.The intermediate complex Ru(ONO)(CO)(NO)(PPh3)2 was synthesized independently and has been characterized by analytical and spectral methods.The thermolysis of Ru(N¹⁸O2)2(CO)2(PPh3)2 unambiguosly establishes coordinated NO2^- as the source of oxygen in the conversion of coordinated CO into CO2.Moreover, the extent of 18O enrichment in the CO2 product indicates that statistical scrambling of oxygen occurs between nitrogen and carbon atoms prior to the loss of CO2.The results of a double-label study involving the thermolysis of Ru(N¹⁸O2)2(CO)2(PPh3)2 and Ru(NO2)2(13CO2)2 are consistent with an intermolecular mechanism for oxygen-atom transfer from NO2^- to CO.Additional mechanistic implications are described.