荧光光谱滴定法研究葫芦脲[7]对亚甲基蓝的包结作用

采用荧光光谱滴定法研究了不同温度下及醋酸缓冲溶液中，葫芦脲7](CB7)对亚甲基蓝(MB)的包结作用。在一定的浓度范围内，体系的荧光强度随着CB7浓度的增大而增强，且荧光峰位有一定的蓝移，结果显示二者形成了1∶1的包结配合物，同时计算了它们的包结稳定常数以及相关热力学常数ΔG,Δh和ΔS,热力学常数数值说明反应是焓变驱动的。此外，利用1H NMR谱图，结合葫芦脲7]以及客体亚甲基蓝的结构特征，对其包结机理及主客体作用模式进行了探讨。

Study on the Inclusion Behavior of Cucurbit[7] Uril with Methylene Blue by Spectrofluorometric Titrations

The characteristics of host-guest complexation between cucurbit ［7］ uril (CB7) and methylene blue (MB) were investigated by fluorescence spectrometry in acetate buffer solution at room temperature. It was found that the fluorescence intensity of methylene blue regularly increased upon the addition of cucurbit ［7］ uril accompanying with a blue-shift of the position of the emission maximum. The results indicate the formation of complex between CB7 and MB at a 1∶1 complex stoichiometry and the association constant was calculated by applying a deduced equation. 1H NMR spectra were applied to to complement the fluorescence work to verify the formation of the complex. From the temperature dependence of the equilibrium constants, thermodynamics parametersH andS values were obtained, indicating an enthalpic driving force for complexation. The possible interaction mechanism was also discussed. This work may extend the application range of cucurbit ［7］ uril in biochemistry and pharmaceutical analysis.