Transition-metal nitrosyl compounds. Part IX. The preparation and study of the osmium cation [OsH2(CO)(NO)L2]+(L = triphenyl- or tricyclohexyl-phosphine

Abstract

The dihydrides [OsH₂(CO)(NO) L₂] PF₆[L = PPh₃(1) or P(C₆H₁₁)₃(2)] have been prepared from the reaction of Os(CO)(NO)L₂Cl and AgPF₆ in the presence of H₂. ¹H N.m.r. data indicate that these compounds are stereo-chemically non-rigid and ΔG^‡_Tc values of 48·5 ± 0·8 kJ mol^–1 and 53·1 ± 0·8 kJ mol^–1 have been determined for (1) and (2) respectively. On reaction with CO the dihydrides readily undergo H₂ displacement to give the salts [Os(CO)₂(NO) L₂] PF₆. Complex (1) reacts similarly with PPh₃ to give [Os(CO)(NO)(PPh₃)₃]PF₆ but complex (2) reacts with P(C₆H₁₁)₃ to form the neutral complex OsH(CO)(NO){P(C₆H₁₁)₃}₂ by H⁺ abstraction.