ORGN 181 |
| Xuefeng Mei and Christian Wolf. Department of Chemistry, Georgetown University, 37th and "O" Streets, Washington, DC 20057 |
| The synthesis and structure of a new class of highly congested C2-symmetric N,N’-dioxides will be discussed. 1,8-Bis(3,3’-(3,5-dimethylphenyl)-9,9’-diacridyl)naphthalene N,N’-dioxide has been designed to (a) embed interactions with chiral molecules into a highly stereoselective environment, and to (b) utilize fluorescence spectroscopy to monitor stereoselective recognition. Single crystal structures of this N,N’-dioxide demonstrate its ability to participate in hydrogen bonding and to operate like a flexible pincer molecule that can accommodate substrates of varying size in its chiral cleft through twisting of the antiparallel acridyl rings. Titration experiments using the enantiopure sensor in the presence of (R)- and (S)-N-t-Boc-valine showed enantioselective fluorescence quenching and an enantioselectivity factor (KSsv/KRsv) of 1.63. By contrast, Stern-Völmer plots using trans-1,2-diaminocyclohexane revealed enantioselective fluorescence enhancement and a remarkable enantioselectivity factor (KRRsv/KSSsv) of 1.50. |
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Asymmetric Reactions and Syntheses, Metal-Mediated Reactions, Materials, Molecular Recognition
8:00 PM-10:00 PM, Sunday, August 22, 2004 Pennsylvania Convention Center -- Hall D, Poster
Sci-Mix
Division of Organic Chemistry |