CCB Colloquium presentation by Dr. Parisa Mehrkhodavandi, University of British Columbia.
Host: Kai Hultzsch
Talk Title: "Chiral Indium Catalysts for Highly Controlled Ring Opening Polymerization of Cyclic Esters"
Abstract: Poly(lactic acid), a leading biodegradable polyester, can be formed by the ring opening polymerization of lactide, a biologically derived monomer. We have developed the first chiral indium catalyst for this transformation. This catalyst is among the most active reported for this transformation. It is also a living polymerization catalyst and we obtain exquisite control of molecular weights and molecular weight distributions in the process. Detailed kinetics studies have elucidated the polymerization mechanism and selectivity data. We can extend the chemistry of this system to the ring opening polymerization of other cyclic esters. Our studies indicate the importance of catalyst aggregation during the initiation period. We are currently investigating the role of the chiral auxiliary and aggregation on the limited isoselectivity we observe in the system.
Douglas, A. F.; Patrick, B. O.; Mehrkhodavandi, P. "A highly active indium catalyst for living polymerization of lactide" Angew. Chem. Int. Ed. 2008, 47, 2290-2293.
Labourdette, G.; Lee, J.-C. D.; Patrick, B. O.; Ezhova, M. B.; Mehrkhodavandi, P.* "Unusually stable chiral ethyl zinc complexes: Reactivity and polymerization of lactide" Organometallics, 2009, 28, 1309-1319.