ORGN 562 |
| Yi Liu and J. Fraser Stoddart. Department of Chemistry and Biochemistry, University of California, Los Angeles, 405 Hilgard Avenue, Los Angeles, CA 90095 |
| The synthesis and characterization of a range of tetracationic cyclophanes, based on the p-accepting cyclobis(paraquat-p-phenylene) with a p-donating tether containing either a hydroquinone, a 1,5-dioxynaphthalene or a tetrathiafulvalene unit will be described. These self-complexing compounds show temperature dependent behavior in solution, commensurate with varying degrees of self-association. In the case of the compound carrying a 1,5-dioxynaphthalene unit in its side arm, two diastereoisomeric, self-complexing conformations are observed below 272 K in deuterated acetone solution. As the temperature of the solution is increased, the unthreaded conformation becomes the dominant species as the entropy gain associated with the dethreading process overcomes the enthalpy loss resulting from the breaking of the donor-acceptor interactions. The thermodynamic parameters associated with the equilibria between the threaded and unthreaded conformations have been unraveled using variable temperature 1H NMR spectroscopy. Applications of this kind of self-complexing molecule will be discussed. |
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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
Sci-Mix
Division of Organic Chemistry |