Rhodium complexes containing the hybrid P,O ligand PPh2NHC(O)Me or its anion, [PPh2NC(O) Me]–

The coordination behaviour of the heterofunctional phosphine ligand PPh2NHC(O)Me towards Rh(I) is reported and examples of neutral and cationic complexes containing mono- or bi-dentate modes of coordination are found. The X-ray structure of [Rh{PPh2NHC(O)Me}(CO)Cl]·CH2Cl2(1·CH2Cl2) shows that the P,O-chelate is almost planar and coplanar with the Rh(I) square-plane. An unusual example of coordination is found in the dimer [Rh{mu-PPh2NC(O)Me}(CO)]2 (2), which contains the bidentate, anionic ligand that bridges two rhodium atoms via the oxygen; it is probable that the neutral ligand can form similar complexes, such as 11 and 12. Displacement of the P,O ligand by CO or RNC ligands occurs in 1 but not in 2.