ORGN 572 |
Chiral self-assembly of zinc porphyrin acid with carboxylic acid derivatives
| Qifei Yang, Courtney C. Olmsted, and Babak Borhan. Department of Chemistry, Michigan State University, East Lansing, MI 48824 |
Exciton Coupled Circular Dichroism (ECCD) is a non-empirical method to determine the stereochemistry of chiral compounds. This method requires two non-conjugated chromophores in the chiral system to interact with each other and exhibits a bisignate spectrum. Zinc bisporphyrin tweezers have been used previously as a chromophoric host system. We have now observed ECCD spectra with zinc porphyrin acids complexed with chiral amides. This unexpected result is probably due to the aggregation of amide-bound porphyrins at low temperatures. The sign of these couplets directly relates to the chirality of the derivatized acid. We propose that the chiral substrate binds to the porphyrin via the zinc, and the acid functionality enables the assembly of the porphyrin by hydrogen bonding. |
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Bioorganic, Molecular Recognition, Asymmetric Reactions and Syntheses
11:00 AM-1:00 PM, Wednesday, September 10, 2003 Javits Convention Center -- Hall 1B/1C, Poster
Division of Organic Chemistry
The 226th ACS National Meeting, New York, NY, September 7-11, 2003
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