Organic Chemistry Seminar: Professor Brooks Abel, University of California, Berkeley
About the Seminar
"Organocatalysts for Controlled Cationic Ring-Opening Polymerizations"
Extensive efforts have been made to synthesize polymers derived from heterocyclic monomers including lactones, lactams, and epoxides among other monomers, and numerous synthetic routes have been developed for their controlled syntheses using anionic ring-opening polymerization (AROP) and coordination catalyst systems. Less explored but equally promising as sustainable materials are polymers derived from heterocyclic monomers that are best polymerized by cationic ring-opening polymerization (CROP). Polymers synthesized by CROP comprise a diverse range of functional groups including acetals, orthoesters, ethers, phosphates, and disulfides among others. Additionally, polymers synthesized by CROP have been explored for their biodegradability and chemical recycling to monomer. However, despite more than half a century of development, CROP of heterocyclic monomers has not yet reached the same level of control over molecular weight, microstructure, architecture, and stereochemistry as has been achieved for AROP systems. This is largely due to undesirable Lewis acid-base interactions between the CROP catalyst and heterocyclic monomer. This presentation will provide an overview of our recent efforts toward the development of organocatalysts for cationic ring-opening polymerizations.
About the Speaker
Brooks Abel is an Assistant Professor in the Department of Chemistry at the University of California, Berkeley and staff scientist in the Materials Science Division at LBL. He received a B. S. in Polymer Science and a Ph.D. in Polymer Science and Engineering (NSF Graduate Fellowship) from the University of Southern Mississippi. His Ph.D. work under the advisement of Prof. Charles McCormick focused on synthesizing stimuli-responsive water-soluble polymers using controlled radical polymerizations for applications such as drug delivery and oil/water remediation. Following his graduate studies, he worked as a postdoctoral researcher with Prof. Geoffrey Coates at Cornell University (2017-2021) where he developed bifunctional Lewis acid catalysts for the alternating ring-opening copolymerization of epoxides and cyclic anhydrides to synthesize well-defined polyesters. While at Cornell, he also developed new methods for living cationic ring-opening polymerization of cyclic acetals, enabling the synthesis of ultra-high molecular weight polyacetal thermoplastics with capable of near-quantitative chemical recycling back to monomer. His independent research interests lie in the areas of sustainable polymer organic chemistry, main group polymerization catalysis, and ionic ring-opening polymerizations.
Host: Yan Xia