含三螺吡喃单元大环分子的合成和酸致变色效应

合成了含有3个螺吡喃单元的大环分子，采用点击化学方法实现高效的闭环反应，大环分子产率为64%。 使用红外、核磁和质谱等方法检测和表征了反应中间产物和目标产物，质谱分析结果证实环化结构。 使用紫外-可见光谱仪观察到大环产物和线性螺吡喃前体分子在pH值接近4时的酸致变色效应。 与线性螺吡喃前体分子的最大紫外吸收峰位置（476 nm）相比，螺吡喃大环分子在最大紫外吸收峰位置（464 nm）发生蓝移。 螺吡喃大环分子比线性前体分子具有更大的摩尔消光系数，其pH响应性能更加优异。

Synthesis and pH-Responsive Chromism of a Macrocyclic Compound with Three Spiropyran Units

A macrocyclic compound containing three spiropyran subunits(macrocyclic spiropyrans) has been synthesized. Click chemistry has been conducted in a dilute solution to construct the cyclic structure of the target product. The yield of macrocylic compound is 64%. The structure of the macrocyclic compounds is characterized by FT-IR, 1H NMR, 13C NMR and ESI-MS. Cyclization of the macrocyclic spiropyrans is confirmed via MS analysis. The pH-responsive chromic properties of macrocyclic spiropyrans and linear compounds have been studied by using UV-Vis absorption spectroscopy in solutions at pH near 4. The maximum UV-Vis absorption(464 nm) of the macrocylic compound exhibits a blue shift comparing with that of linear compounds(476 nm). It is found that the molar extinction coefficient of the maximum UV-Vis absorption of macrocyclic spiropyrans is greater than those of its linear precursors. Furthermore, macrocyclic spiropyrans shows more sensitive pH-responsivity than its linear precursors.