ORGN 279 |
| Photo-/electroactive donor-acceptor (D-A) chromophores were designed/synthesized and investigated for energy- and electron-transfer (ET/eT). The chromophores are supramolecularly integrated into helical cavity of amylose to generate a single molecular encapsulation by the helix. This renders the chromophore rigidified along the helical axis and aggregation-free, leading to a remarkable fluorescence enhancement. ET/eT of the D-A chromophores were investigated using fluorescence quenching in the presence and absence of the helical encapsulation, and the transporting properties are discussed with respect to D-A distance, D/A strength and solvent effect. ET/eT of the encapsulated chromophores show a clear dependence on D-A distance, while those of the encapsulation-free counterparts have no discrete distance dependence, suggesting that the fluorescence quenching involves other quenching sources including aggregations than ET/eT. Such differences in ET/eT behavior are well reflected in their florescence decay profile. Another notable difference is that the helical supramolecule of the chromophores is capable of a self-assembly, whereas either the free chromophores or the helix alone is unable to do. The assembly features and substrate binding are also discussed.
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Materials, Molecular Recognition and Self-Assembly
8:00 AM-12:00 PM, Monday, 11 September 2006 Moscone Center -- Room 132, Oral
Division of Organic Chemistry |