Dioxygen oxidation of a carbonyl ligand to form a chelating peroxycarbonyl ligand: synthesis, structure, and reactions of Cl(NO)(PPh3)2

Reaction between the carbonyl, nitrosyl complex, OsCl(CO)(NO)(PPh3)2 (1) and dioxygen results in combination of CO and O2, forming a chelating peroxycarbonyl ligand in the yellow complex, Cl(NO)(PPh3)2 (2). Confirmation of the unique peroxycarbonyl ligand arrangement in 2 is provided by crystal structure determination. When 2 is heated, as a suspension in heptane under reflux, there is a rearrangement to the regular chelating carbonate ligand in the orange complex, Cl(NO)(PPh3)2 (3). The structure of 3 has also been determined by X-ray crystallography. Compound 2 also undergoes the following reactions: with water, releasing CO2 and forming Os(OH)2Cl(NO)(PPh3)2 (4); with HCl releasing CO2 and forming Os(OH)Cl2(NO)(PPh3)2 (5); and with excess triphenylphosphine releasing CO2 and triphenylphosphine oxide forming OsCl(NO)(PPh3)3 (6).