Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bucharest, Romania.
Spectrochim Acta A Mol Biomol Spectrosc. 2012 Jun 15;92:56-63. doi: 10.1016/j.saa.2012.02.027. Epub 2012 Feb 17.
The association process of a host-guest system, cyclodextrins (CyD) - 3-carboxycoumarin acid (3CCA) was followed by means of UV-vis, circular dichroism and steady-state fluorescence spectroscopies in buffer solution at pH=1. The experimental data were analyzed in order to get information on the stoichiometry, the equilibrium constants and the geometry of the inclusion complexes. In the circular dichroism spectra, a positive induced signal was obtained reflecting that the guest penetrates the cavity in such a way that the transition moment of the electronic band is quasi parallel to the host main axis. The experimental data are supported by the DFT and TDDFT (B3LYP/6-31G) calculations performed on the isolated ligand and by TDDFT (ZINDO) calculations carried out on the supramolecular ligand-cyclodextrin system.
在缓冲溶液 pH=1 条件下，通过紫外-可见光谱、圆二色光谱和稳态荧光光谱研究了主体-客体体系中环糊精（CyD）-3-羧基香豆素酸（3CCA）的缔合过程。通过分析实验数据，得到了包合物的化学计量比、平衡常数和几何构型等信息。在圆二色光谱中，得到了一个正的诱导信号，反映了客体以一种方式进入主体空腔，使得电子能带的跃迁矩几乎与主体主轴平行。实验数据得到了孤立配体的密度泛函理论和含时密度泛函理论（B3LYP/6-31G）计算以及超分子配体-环糊精体系的含时密度泛函理论（ZINDO）计算的支持。
