Application Of The Redox Control And Heterobiaryl Substituted Phosphine-Sulfonate Ligands In Olefin Polymerization

In metal catalytic homogeneous polymerization of ethylene,designing and improve of ligand plays an important role.Because of the different performance of ligands may greatly change the performance of catalyst.Different monomer composition and microstructure have a great influence on the physical properties of the polymer,and we can get the ideal product through the design of ligand structure.At present,phosphine sulfonate nickel and palladium catalyst has been widely recognized,in the ethylene homopolymerization and the copolymerization of ethylene with polar monomers have excellent catalytic performance.People have invested a lot of energy to design and synthesis new phosphine sulfonate ligand with the hope of getting more excellent metal catalysts.So design phosphine sulfonate ligand become the focus of this article.1.Two phosphine sulfonate ligands and the corresponding nickel and palladium complexes have were prepared and characterized.Two phosphine sulfonate ligands bear both the ferrocene and the bi-aryl units.All the metal complexs are active in ethylene polymerization.But after the ferrocene unit been oxidized,the catalytic activities and the polymer molecular weights both are decreased.Interestingly,the neutral palladium catalyst can not catalyze the polymerization of norbornene while the oxidized analogue showed good activity.As such,switchable polymerization could be achieved.2.A series of phosphine sulfonate ligands with heterocyclic unit have been prepared and characterized.And we studied the corresponding nickel and palladium catalytic performance.The palladium complexs with furyl and benzofuryl units have great catalytic activities for ethylene polymerization and copolymerization with polar monomers.And the nickel complexs with furyl and benzofuryl units also show high activities for ethylene polymerization.The palladium and nickel complexs with the N-methylpyrrolyl,thienyl,and benzothienyl units shows low or no activities in ethlyene polymerization.The microstructure of polymer(highly linear vs.highly branched)are affected by the nature of heterocyclic substituent.