通过N,N-二乙基-4-(二氯代-1,3,5-三嗪-2-基)苯胺分别与单-[6-(乙二胺基)-6-脱氧]-伊环糊精和单-[6-(二乙烯三胺基)-6-脱氧]移环糊精反应合成了两种三嗪基苯胺桥联双环糊精,采用荧光和紫外光谱滴定方法测定了它们在磷酸缓冲溶液中(25℃,pH=7.2)与几种具有不同形状和电子密度的染料分子包结配位的稳定常数.结果表明,三嗪基苯胺桥联双环糊精不但对具有较大电子密度的三角形客体结晶紫给出了6~26倍于天然环糊精的配位稳定常数,而且对结晶紫,中性红分子对给出了高的分子选择性(Kcv/KNR=23~31).分子力学研究表明,桥联双环糊精对客体分子的强键合能力主要源于两个环糊精空腔及桥链基团对客体分子的协同键合,特别是桥链中三嗪基苯胺基团与客体之间的π-π相互作用.
Two triazinylanilino-bridged bis(β-cyclodextrin)s were synthesized by the reactions of N,N-diethyl-4-(4,6-dichloro-1,3,5-triazin-2-yl)aniline with 6-ethylenediamino-6-deoxy-β-cyclodextrin and 6-diethylenetriamino-6-deoxy-fl-cyclodextrin. The complex stability constants for the inclusion complexa- tion of these bis(β-cyclodextrin)s with several dyes possessing different shapes and electron intensities were determined by means of fluorescence and UV-Vis titrations at 25℃ in phosphate buffer solution (pH 7.2). The results show that the triazinylanilino-bridged bis(β-cyclodextrin)s exhibit not only the high complex stability constants, i.e. 6-26 times higher than that of native β-cyclodextrin, for triangular guest crystal violent that possesses a larger electron intensity, but also the high molecular selectivity for crystal violent/neutral red pair (Kcv/KNR=23~31). Molecular dynamics studies show that the strong binding ability of triazinylanilino-bridged bis(β-cyclodextrin)s can be mainly attributed to the cooperative binding of two cyclodextrin cavities and the bridge chain, especially the π-π interactions between the triazinylaniline group in the bridge chain and the guest dye.