柱[5,6,7]芳烃分子识别基元的确立及键合机理研究

Pillar[n]arenes are a new class of macrocyclic receptors. They are made up of hydroquinone units linked by methylene bridges at the 2 and 5 positions, and possess symmetrical pillar architectures. In the past few years, pillararenes have shown fascinating host-guest properties. However, the binding mechanisms, driving forces, and thermodynamic origins still need further study. Therefore, in this project we will design and synthesize a series of mono-, di-, half-, and fully-substituted pillararenes and pillararene dimers, and study their recognition abilities and binding behavior towards various organic neutral molecules, metal ions and organic cationic guests with spectroscopy, NMR, and isothermal titration microcalorimetry, etc. The study is expected to identify some highly effective and selective pillar[5,6,7]arene-based recognition motifs, clarify the driving forces, and discuss the relationship between the host-guest structures and the thermodynamic data. Additionally, the complexation mechanisms, structures and the themodynamic properties of different types of supramolecular assemblies based on the pillararene recognition motifs, such as dimers, oligomeric rings and linear polymeric chains, will be studied. The proposed work is beneficial to clarify the control factors during the process of pillararenes' recognition and assembly, and therefore help to provide referrence data and lay a foundation for pillararenes' application and development in supramolecular chemistry.

柱芳烃是一种新型的大环受体分子，它是由对苯二酚通过亚甲基在2、5位相连接而形成的柱状大环化合物。在短短几年时间里，柱芳烃已展现了独特的主客体性质，然而有关柱芳烃键合客体的规律、驱动力和热力学起源还有待深入研究。因此，该项目拟设计和合成单取代、二取代、半取代、全取代柱芳烃及桥联柱芳烃等一系列衍生物，通过光谱、核磁、量热等手段研究它们对各种类型的有机中性分子、金属离子和有机阳离子等客体的键合行为。通过合成衍生，确立具有强键合、高选择性识别能力的柱[5,6,7]芳烃分子基元，探索其分子识别过程的驱动力，并阐述功能柱芳烃主体键合客体分子的结构和热力学参数之间的关系。进而考察基于柱芳烃分子基元构筑各种类型高级组装体（如互插型二聚体、环状寡聚体和超分子聚合物等）的结构规律和热力学性质。这些研究将有益于阐明柱芳烃分子识别与组装过程的控制因素，这将为推动柱芳烃超分子化学的发展提供数据参考、奠定基础。

自2008年发现以来，柱芳烃已发展成为超分子化学领域一类重要的大环受体分子。在过去四年里，我们小组在柱[5,6,7]芳烃分子识别与组装领域进行了探索：研究了柱[5,6,7]芳烃及其衍生物对一系列有机阳离子、阴离子、中性分子、生物分子和药物分子的识别性质，探讨了主客体络合的热力学、驱动力和规律。利用我们发展的柱芳烃独特的对中性分子强络合行为，设计了一个适于柱芳烃超分子组装的、已被多个课题组使用的优异主客体基元；进而制备了AA/BB、AB2和A2B3等类型超分子聚合物、基于互插二聚体（[c2]daisy chain）的超分子交替共聚物以及空腔包结和外壁π...π堆积共同驱动的线性聚合物等超分子聚集体；同时考察了这些组装体的环境响应性，讨论了柱芳烃模块自组装构筑互插二聚体、寡聚体和聚合物等高级结构的影响因素。基于柱芳烃优异的分子识别性质，在药物递送和毒物传感等功能应用方面也取得了初步的进展。