Carbonyl nitrosyl derivatives of rhodium and their reaction with silver nitrate

Summary Solid sodium nitrite and moderately concentrated hydrochloric acid react with ittrans]-Rh(CO)XL₂ (X = Cl, Br, I and L = PPh₃, AsPh₃) dissolved in either DMF or CHCl₃ to yield carbonyl nitrosyl derivatives of the type Rh(CO)(NO)L₂XCI. These brown crystalline products are monomeric nonelectrolytes. Their absorption bands atca. 1630 cm^–1 andca. 2 100 cm^–1 indicate the presence of nitrosyl as well as carbonyl groups. Silver nitrate reacts with the Rh(CO)(NO)L₂XCI complexes to yield pentacoordinate species having the general composition Rh(NO)(NO₃)₂L2.