Chemistry Seminar: Tae-Lim Choi
About the Seminar: Alkyne is a highly versatile functional group in field of organic chemistry. Here, we will describe new polymerization from various monomers containing alkynes. The first example is cyclopolymerization of diynes using Grubbs catalysts. Our strategy to achieve controlled polymerization to prepare polymers with desired molecular weights and narrow polydispersity indices will be discussed. Then, cascade or tandem olefin metathesis polymerization using Grubbs catalysts will be introduced. This polymerization initiates from alkynes to give highly chemo- and regio-selective transformation. The resulting polymers contains diene which then can undergo very efficient Diels-Alder reaction to give polymers containing heterocycles. The last polymerization is multi-component polymerization using Click-like three component coupling reaction catalysed by Cu. Various polyamidines and polyamidates were prepared from three monomers containing alkynes, electron-deficient azides and amines or alcohols. Due to the versatility of the reactions, diversity-oriented polymerization to highly well-defined polymers with high molecular weight is now possible. As the second part, we will briefly introduce a new concept of self-assembly termed “in situ nano-particlization of conjugated polymers”. This method produces supramolecules directly during the polymerization and no further post-modification is required.
References1. Kang, E.-H., Lee, I. S., Choi, T.-L. J. Am. Chem. Soc. 2011, 133, 11904; Kang, E.-H., Yu, S. Y., Lee, I. S., Park, S. E., Choi, T.-L. J. Am. Chem. Soc. 2014, 136, 10508.2. Park, H., Choi, T.-L. J. Am. Chem. Soc. 2012, 134, 7270; Park, H., Lee, H.-K., Choi, T.-L. J. Am. Chem. Soc. 2013, 135, 10769; Park, H., Kang, E. -H., Muller, L., Choi, T.-L. J. Am. Chem. Soc. 2016, 138, 22443. Lee, I.-H. Kim, H.-S. Choi, T.-L, J. Am. Chem. Soc., 2013, 135, 3760; Kim, H. Bang K.-T. Choi, I, Lee, J.-K. Choi, T.-L. J. Am. Chem. Soc. 2016, 138, 8612
About the Speaker: Tae-Lim Choi was born in Seoul, 1977. He obtained BS from KAIST, Daejeon, S. Korea in 1999, and Ph. D degree from Caltech under supervision of Bob Grubbs, in 2003. Then he moved to UC Berkeley as a post doc researcher under guidance of Jean Frèchet until 2004. Then, he came back to S. Korea and worked at Cheil Industries, one of Samsung research centers for four years. Since 2008, he started his independent career as assistant and associate professor at Department of Chemistry, Seoul National University. His group focuses on developing new methods to synthesize various macromolecules, understanding their catalytic mechanisms and their self-assembly behaviors. Since 2013, he is serving as an editor of Journal of Polymer Science, Part A: Polymer Chemistry (Wiley).