The Application Of External Stimulation Of Diimine Kind Catalysts In Olefin Polymerization And Ring-Opening Polymerization

As a big branch of the polymerization method,coordination polymerization has been taking an important part in polymer synthesis.And they were especially investigated extensively in olefin polymerization and ring-opening polymerization realms.While the focus in these realms have been changed from the design of new catalysts structure to new modulation strategies during polymerization.In olefin polymerization and ring-opening polymerization realms,each has it's own modulation strategies.If we can borrow ideas from each other,fulfill the application of modulation strategies from one realm to the other,our horizon will be expended.Redox control was firstly reported applied in modulating the ring-opening polymerization of rac-lactide,while lewis acid Modification was first applied in the realm of olefin polymerization.In the late 1990s,the a-diimmine palladium catalyst was reported by Brookhart,it can polymerize ethylene,copolymerize ethylene with polar monomer like MA,NB and NB-OAC.In 1998 Coates reported that ?-diimine Zinc catalyst can initiate the ring-opening polymerization of rac-lactide efficiently and the polymers obtained possess high chiral selectivity.Therefore,our work focus on diimine kind metal catalysts,attempt to respectively fulfill the application of redox control in olefin polymerization and lewis acid Modification in ring-opening polymerization.1:We designed and synthesized a king of an a-diimine palladium catalyst with two ferrocenyl units,the redox process of ferrocene is quasi-reversible,and wo have two ferrocenyl units in Symmetric position of the catalyst,it can be oxidized in a stepwise fashion.This stepwise redox control can be used to modulate the catalyst properties during the homopolymerization of ethylene and 1-hexene,as well as the copolymerizations of ethylene with norbornene,methyl acrylate,and 5-norbornene-2-yl acetate.Moreover,polymer microstructure and polydispersity can be controlled during these stepwise oxidation processes.2:A kind of ?-diimine Zinc catalyst bearing cyano groups on the three-position of the backbone was synthesized,and it's catalytic properties were investigated.Then wefocus on the investigation of the change of catalytic properties after the addition of lewis acid.