六、七、八元瓜环与苯胺系列衍生物的相互作用

利用紫外吸收光谱、荧光光谱以及¹H NMR方法详细考察了六、七、八元瓜环(Q6], Q7], Q8])与苯胺系列衍生物客体的相互作用和体系pH对其作用的影响. 实验结果表明, 3种瓜环与苯胺系列衍生物客体的相互作用强弱、作用比例以及作用模式与体系的酸度密切相关: 在“高”或“低”pH条件下, 未观察到瓜环与这些客体的明显作用; 在介于“高”与“较高”或“低”与“较低”的pH范围, 瓜环与这些客体发生相互作用, 形成1∶1的包结配合物; 而在介于“较高”与“较低”的pH范围, 瓜环与这些客体发生相互作用, 可形成1∶2的包结配合物. 对于不同的瓜环-客体作用体系, 相应的pH范围各不相同. 本文利用简便的实验方法, 测试了这些pH值及其范围. 根据测定的结果, 结合瓜环以及客体的结构特征, 对体系主客体在不同的酸度区域表现出的不同作用模式进行了探讨.

Interaction of Cucurbit[n=6, 7, 8] with Aniline and Its Derivates

Interaction of cucurbitn＝6, 7, 8]urils(Q6], Q7], Q8]) with aniline and its derivates and influence of pH on the interaction were studied by using UV spectroscopy, fluorescence spectrophotometry and ¹H NMR technique in details. The experimental results revealed that the interaction, such as interaction models and ratio of the interacted Qn] with the guest, is closely related with pH of a host-guest system. Generally, there are five interaction stages: there is no obvious interaction between Qn] and the title guest(s) at the “highest” and the “lowest” pH; the Qn] includes the guest with a 1∶1 ratio between the “highest” and a “higher” pH or the “lowest” and a “lower” pH; between the higher and the lower pH, the Qn], even some Q6]-guest systems, includes the guest with a 1∶2 ratio. However, the values of the “highest”, “higher” “lowest” “lower” pH are different for different Qn]-guest systems, and in this work, a relevant simple method was used to determine these different pH values. Based on the experimental results, the structure of the Qn] and the guests, the reasons of different interaction models and ratio at different pH were discussed.