Substituted carbonyl derivatives of the Group VI transition metals. III. Complexes with π-bonded bridging triarylphosphines

Abstract

The reactions of chromium hexacarbonyl with triphenylphosphine, tri(m- tolyl)- phosphine (pmt), and tri(p-tolyl)phosphine (ppt) at high temperature yield two series of complexes Cr(CO)₃L and [Cr(CO)₂L]₂, although only the latter could be isolated in a pure state. These dimeric derivatives were characterized by analysis, infrared, N.M.R., and mass spectral measurements. All the data are consistent with a molecular arrangement incorporating π-bonding between chromium and one of the arene rings of the ligand which is also σ-bonded through phosphorus to the other metal atom, thus forming a novel, highly unsymmetrical bridge system.