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REPORT: Heavy Group-16 Chemistry in Polymers and Molecules
Nov 3, 2014

Topic:Heavy Group-16 Chemistry in Polymers and Molecules
Speaker:Prof. Dwight Seferos
              Department of Chemistry, University of Toronto, Canada
Time:2014/11/6 (Thursday) 15:30
My research group focuses on the chemistry of selenophene and tellurophene heterocycles. We have recently developed selenophene-thiophene block copolymers and discovered that these rod-rod copolymers undergo a significant amount of phase separation. This is surprising given the chemical similarities between repeat units, however we have uncovered several properties, including crystal packing, that differ in these polyheterocycles. By suppressing crystallization though size chain engineering we are able to achieve solid-state morphology that is reminiscent of classical lamella-type micro structure, which is very uncommon for crystalline polymers. In other work we have increased the compatibility of the selenophene and thiophene units and we observe co-crystallization in statistical copolymers.  These statistical copolymers form nanowires and when fabricated into nanowire solar cells they operate with a greater efficiency than cells composed of homopolymer nanowires. We have also learned how to synthesize polymers and delocalized molecules based on tellurophene, and identified several unexpected properties in these materials including reversible binding of small molecules, and the ability to photo-reductively eliminate halogens including Br2, Cl2 and even F2. Recently we have been focusing on so-called ‘n-type’ organic materials. We have developed thionated perylene diimides are applying these materials for transistors and as acceptors in singlet fission solar cells. We have also used nickel catalysts to prepare well-defined electron deficient polymers and fully p-conjugated donor-acceptor
Selected References:
[1] Hollinger, J.; Jahnke, A. A.; Coombs, N.; Seferos, D. S. J. Am. Chem. Soc. 2010, 132, 8546-8547.
[2] Jahnke, A. A.; Howe, G.; Seferos, D. S. Angew. Chem. Int. Ed. 2010, 49, 10140-10144.
[3] McCormick, T. M.; Jahnke, A. A.; Lough, A. J.; Seferos, D. S. J. Am. Chem. Soc. 2012, 134, 3542-3548.
[4] Gibson, G. L.; McCormick, T. M.; Seferos, D. S. J. Am. Chem. Soc. 2012, 134, 539-547.
[5] Jahnke, A. A.: Djukic, B.; McCormick, T. M.; Domingo, E. B.; Hellmann, C.; Lee, Y;

Seferos, D. S. J. Am. Chem. Soc. 2013, 135,  951.
[6] Bridges, C. R; McCormick, T. M.; Seferos, D. S. J. Am. Chem. Soc. 2013, 135, 13212-13219



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