Synthesis of stereochemically controlled functionalized vinyl polymers and polyesters by metallocene-based catalysts

Abstract

The research presented herein studies the polymerization of functionalized alkenes (methacrylates and acrylamides) and cyclic esters (lactide and lactone) catalyzed by group 4 metallocene complexes. Key findings of this study include: (1) development of the novel diastereospecific ion-pairing polymerization effected by a catalyst system comprising a chiral C 2-zirconocene bis(ester enolate) and two equiv of lewis acid Al(C 6F5)3, producing polymers with isotactic, syndiotactic, and isotactic-b-syndiotactic multiblock microstructures, (2) development of the highly syndiospecific polymerization by C s-ligated ansa-zirconocene bis- and mono(ester enolate) complexes at room temperature, and (3) development of quantitatively isospecific polymerization of L-lactide by Cs-ligated ansa-zirconocene bis- and mono(ester enolate) complexes. The broad focus of this dissertation concerns the kinetic and mechanistic studies of the polymerization of functionalized alkenes and cyclic esters, which provided several novel and useful polymerization systems.