用紫外吸收光谱、稳态荧光、荧光各向异性和动态光散射等方法研究了2,2′-p-亚苯基-双(5-苯基噁唑)(POPOP)分子与环糊精(CD)的相互作用.结果表明,POPOP分子在浓度较低时与β-CD形成1:2的包合物,在浓度较高时可以进一步诱导β-CD形成纳米管结构.同时发现,POPOP分子也可以诱导γ-CD形成纳米管结构.对比于β-CD,POPOP分子在γ-CD水溶液中的荧光发射峰,不仅有明显的红移而且也缺失了精细结构,呈现较宽的大包峰.这是由于POPOP分子成对进入γ-CD空腔形成了激基缔合物的缘故.pH和温度效应实验进一步表明,POPOP诱导β-CD形成的纳米管在pH大于12和温度高于331K的环境下不能稳定存在.
The interaction between 2,2'-p-phenylenebis (5-phenyloxazol) (POPOP) and cyclodextrins (CDs) was investigated using UV-Vis absorption, steady-state fluorescence, and dynamic light scattering (DLS). The results indicated that POPOP could form the 1:2 (guest:host) inclusion complex with β-CD at lower concentrations, which could further form the extended nanotube at higher concentrations. POPOP could also induce the formation of the nanotube of γ-CD. The fluorescence emission of POPOP in aqueous solution of γ-CD showed obvious red shift accompanied by the disappearance of free structure compared with that in aqueous solution of β-CD, which could be attributed to the formation of the excimer of POPOP in the larger cavity of γ-CD. It was found that at pH greater than 12, the hydrogen bond between the neighboring CDs was destroyed, which led to the collapse of the nanotubular structure. The results also showed that the nanotube structure was not stable at temperatures above 331 K.