Novel Single-Component Palladium(II) Catalysts for the Alternating CO/Propene Copolymerization Reaction

A synthetic route for the preparation of 1,3-bis[diphenylphosphino]propane-1η2,5η1-6-ethoxy-exo-5,6-dihydrodicyclopentadienylpalladium(II) hexafluoroantimonate (3a) and the tetrafluoroborate derivative (3b) is described. 3a was characterized by single-crystal X-ray structure analysis. Both species are active for the CO/α-olefin copolymerization reaction without any additional activator or cocatalyst. The copolymerization experiments performed with this single-component catalyst (SCC) produced CO/α-olefin copolymers with similar properties compared to those resulting from the well-known di-acetonitrile-1,3-[bis(diphenylphosphino)propane-Pd(II)-bis(tetrafluoroborate) complex activated with methanol. An increase of activity and molecular weight has been achieved through polymerization in liquid propene.