Fluorimetric study on the charge transfer behavior of trans -ethyl-( p -dimethylamino cinnamate) and its derivative in cyclodextrin cavities
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- 作者：T. Sanjoy Singh and Sivaprasad Mitra
- 关键词：Intramolecular charge transfer (ICT) fluorescence ; Cyclodextrin ; Hydrophobic effect ; Fluorescence lifetime and anisotropy ; Binding constant
- 刊名：Journal of Inclusion Phenomena and Macrocyclic Chemistry
- 出版年：2009
- 出版时间：April, 2009
- 年：2009
- 卷：63
- 期：3-4
- 页码：335-345
- 全文大小：704.3 KB
文摘
The intramolecular charge transfer (ICT) property of trans-ethyl p-(dimethylamino) cinnamate (EDAC) and its acid derivative, p-(dimethylamino) cinnamic acid (DMACA), is used to monitor the encapsulation behavior of these probes into the cyclodextrin (CD) nanocavities by steady state and picosecond time-resolved fluorescence spectroscopy. The ICT fluorescence band intensity was found to increase with concomitant blue shift in presence of cyclodextrins. The encapsulation behavior was further characterized by increase in emission yield, fluorescence anisotropy as well as lifetime values. Detailed analysis of the spectroscopic data indicate that the probes enter through the dimethyl amino group pointing to the secondary rim of the doughnut-shaped hydrophobic cavities to form 1:1 complex at different pH, however, the extent of penetration is more for EDAC compared with DMACA.