第二模板定位下高阶索烃的制备及其应用研究

Mechanically interlocked structures, such as catenanes, have attracted a great deal of attention not only because of their topological importance but also due to their potential applications in molecular machines, nanotechnology, biological materials, and supramolecular polymers. Herein, aiming to the difficulty in the synthesis of complicated catenanes, we intend to introduce covalently-linked small molecules or discrete Pt(II)-based coordination-driven self-assemblies as a secondary template, by which several crown ether derivatives can be pre-organized together. The pre-organized crown ethers will be then threaded by the guests, such as dialkylammoniums and paraquat derivatives, to form the corresponding poly[2]pseudorotaxanes. After that, the guests in self-assembled poly[2]pseudorotaxanes will be covalently connected each other via dynamic olefin metathesis reaction, and the secondary template will be subsequently dissociated to fabricate a series of multi-component, intricate [n]catenanes in high yields. These crown ether-based [n]catenanes can be driven by the stimuli of acidity/basicity in solution to form a new kind of artificial molecular machines, in which several hosts moved simultaneously. These [n]catenanes will be further polymerized to construct hyperbranched polycatenanes. The artificial molecular machines based on these topologically complicated polycatenanes will be then realized by changing acidity/basicity. The presented proposal will provide an opportunity to open a new way for the synthesis of intricate mechanically-interlocked molecules, especially for the synthesis of complicated [n]catenanes, as well as to establish good foundation for the applications of [n]catenanes in artificial molecular machines and supramolecular polymers.

索烃等机械互锁结构不仅具有重要的分子拓扑学意义，而且在分子机器、纳米技术、生物材料、超分子聚合物等领域有着巨大的应用前景。本项目拟针对高阶索烃制备困难的问题，利用共价连接的小分子或离散型的铂配位组装体为第二模板，将多个冠醚主体预组织在一起，然后与二级胺盐、百草枯衍生物等客体络合形成互穿的多准轮烷结构，再通过动态共价的烯烃复分解反应使这些良好“定位”的客体分子之间相互反应形成共价键，将第二模板解离后，可望高效地制备得到一系列基于冠醚衍生物的高阶[n]索烃。利用溶液酸/碱调控等方法驱动这些[n]索烃形成一类多组分同时运动的新型分子机器。将高阶索烃交联聚合制备超支化的聚索烃，开发具有新颖拓扑结构的机械互锁型超分子聚合物；并实现对该类聚索烃的酸/碱调控分子机器运动。本项目的开展有望为复杂机械互锁结构——特别是高阶[n]索烃——的制备探索一条新思路，并实现它们在分子机器和超分子聚合物等领域中的应用。

本项目针对多组分高阶索烃制备困难的问题，设计、合成了一系列新型的冠醚、基于冠醚的三桥大环主体和二级胺盐、百草枯盐等客体，通过金属配位驱动自组装制备了一系列含多个冠醚或三桥大环主体的自组装体，并研究了这些自组装体与二级胺盐、百草枯盐等客体的主客体络合，发展了新型的主客体识别体系。通过模板导向法和利用高效、动态共价的烯烃复分解反应或亚胺键形成反应制备了一系列具有复杂拓扑结构的高阶索烃，并通过主客体化学和配位驱动自组装的正交策略，高效制备了一系列动态可逆的新型索烃和分子项链。此外，通过基于三桥大环主体的主客体化学和金属配位驱动自组装的正交策略构筑了一种AA-BB型的新型线性超分子聚合物和一种具有交联网络结构的新型超分子聚合物。本项目的开展为索烃和分子项链等复杂机械互锁结构的制备提供了一些新方法和新思路，也为新型超分子聚合物的构筑提供了一种新策略。