Cyclometallated complexes of ruthenium and osmium containing the o-C6H4PPh2 ligand

The reaction between [Hg(o-C6H4PPh2)2] and [MHCl(CO)(PPh3)3] gives the complexes [Ph2)(CO)(PPh3)2] [M=Ru (1), Os (2)], which contain a four-membered cyclometallated ring. A single-crystal X-ray diffraction study of 2 shows the geometry about osmium to be distorted octahedral with the phosphorus atoms in a meridional arrangement. Both complexes react with CO, which displaces one of the triphenylphosphine ligands, the product from 2 being [Ph2)(CO)2(PPh3)]. In the case of 1, there is an accompanying migratory insertion of coordinated CO into the RuC bond to give the five-membered cyclic acyl complex [Ph2)(CO)2(PPh3)]. Complex 2 reacts with AgSbF6 in the presence of CO to give [Ph2)(CO)2(PPh3)2]SbF6.