ORGN 505 |
| Thioketones show interesting photophysical and photochemical properties, including fluorescence from second excited singlet state (S2) and phosphorescence from T1 state at room temperature. But, generally the emission from singlet and triplet excited states are quenched at diffusion-limited rates by ground state thione, oxygen and solvent molecules. We have circumvented the bimolecular quenching phenbomenon by isolating the thione molecule(s) within the hydrophobic pockets of a water-soluble cavitand (Figure 1a). Structures of the supramolecular complexes have been analyzed by 1HNMR. Phosphorescence observed at room temperature at high concentrations (Figure 1b) and in presence of oxygen suggested that thioketone molecules are isolated and caged within a capsule. Quenching the phosphorescence emission by oxygen was found to occur in less than diffusion controlled rates.
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Physical Organic Chemistry, Metal-Mediated Reactions, Asymmetric Reactions and Syntheses
8:00 PM-10:00 PM, Tuesday, August 21, 2007 BCEC -- Exhibit Hall - B2, Poster
Division of Organic Chemistry |
