Download or read book Polymer Design Enabled by Catalysis written by Sean Gitter and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modern synthetic polymer chemistry is defined by control over macromolecular architecture. Among controlled polymerization schemes, ring-opening metathesis polymerization (ROMP) represents one of the most widely adopted strategies for precision polymer synthesis. Advances in metal-alkylidene initiator technologies have enabled access to polymers with unrivalled degrees of microstructural control via ROMP. Unfortunately, relying on stoichiometric amounts of organometallic initiators can be cost prohibitive and limit the utility of ROMP materials in metal-sensitive applications like biomedicine or electronics. Therefore, recent effort has been devoted to developing metal-free approaches to ROMP (MF-ROMP). The Boydston group has developed a strategy which relies on organic initiators and photoredox catalysts to achieve MF-ROMP. Despite precluding the deleterious metallic byproducts inherent to metal-mediated ROMP, MF-ROMP remains limited in comparison to metal-mediated approaches to ROMP. Outstanding challenges in MF-ROMP include achieving a high degree of control over polymer microstructure, the incorporation of functional (co)monomers in MF-ROMP materials, and conducting polymerizations in nonpolar media. My doctoral research has begun to address these challenges. First, I was part of a collaborative team that discovered an ion-pairing approach to stereoselectivity during MF-ROMP that affords materials with tunable alkene stereochemistry using simple to change reaction parameters. During a further investigation we discovered that ion-pairing can also be used to improve the molecular weight control of MF-ROMP. These findings directly led to the discovery that active esters are readily polymerizable under MF-ROMP conditions. Post-polymerization modification of these materials provided access to a diverse array of functionalized MF-ROMP polymers for the first time. Separately, I was also on a team that developed a method for the C-H functionalization and allylic amination of ROMP polynorbornenes (poly(NBEs)). Notably, our approach to C-H functionalization yielded materials with high and tunable degrees of amination without consuming or transposing the alkenes in the polymers' backbones. In combination these discoveries highlight the utility of catalysis to access polymeric architectures that are otherwise inaccessible.