Multichromophoric Cyclodextrins. 8. Dynamics of Homo- and Heterotransfer of Excitation Energy in Inclusion Complexes with Fluorescent Dyes
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- 作者：Mario N. Berberan-Santos ; Patricia Choppinet ; Aleksandre Fedorov ; Ludovic Jullien ; and Bernard Valeur
- 刊名：Journal of the American Chemical Society
- 出版年：2000
- 出版时间：December 6, 2000
- 年：2000
- 卷：122
- 期：48
- 页码：11876 - 11886
- 全文大小：171K
- 年卷期：v.122,no.48(December 6, 2000)
- ISSN：1520-5126
文摘
The water-soluble ![]()
C="/images/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-cyclodextrin, CD-St, with seven steroidic naphthalene chromophores linked tothe primary rim, can form inclusion complexes with a merocyanine dye (DCMOH) and an oxazine dye (Ox725);the stoichiometry is 2:1 (CD-St:dye). This system works as an antenna since the dye is surrounded by 14chromophores. The efficiency of transfer from the antenna chromophores to the encased dye was found to beclose to 100%. The dynamics of this heterotransfer and homotransfer (i.e., energy hopping among the antennachromophores) was investigated by time-resolved fluorescence intensity and time-resolved fluorescenceanisotropy experiments, respectively. The distribution of rate constants for homotransfer was recovered thanksto a previously described Monte Carlo simulation from which an average rate constant was calculated andfound to be about 4 × 1011 s-1. This value is about 10 times faster than the rate constant for heterotransfer inthe case of Ox725, and about three times faster than in the case of DCMOH. The results are discussed interms of interchromophoric distances, mutual orientations and Förster radii.