双轴互锁分子的构筑

Design and synthesis of novel mechanically interlocked molecules are a challenging research topic. Based on the characteristics of the resulting 1:2 complex between bis-p-phenylene-34-crown-10 and the secondary dibenzylammonium salts as well as the 1:1:1 ternary complex of cucurbit[8]uril with methylviologen and hydroxynaphthalene, we will design and synthesize a series of the alkynyl-substituted linear dibenzylammonium salts, voilogen cations, and hydroxynaphthalene derivatives in this project, and then prepare the twin-axial pseudorotaxanes, in which bis-p-phenylene-34-crown-10 or cucurbit[8]uril are the wheel components, and two dibenzylammonium salts or one voilogen and one hydroxynaphthalene derivatives are the axel components. Furthermore, the wheel-axle-isolated twin-axial hetero[7]rotaxanes will be prepared by the CuAAC reaction of the twin-axial pseudorotaxanes and a pseudorotaxane possessing azide group, while the wheel-axle-coupled twin-axial hetero[7]rotaxanes will be synthesized by threading linear dibenzylammonium cations to the rings of crown ethers in the twin-axial [3]rotaxane, and then stoppering the axial molecules. On this basis, we further thread the alkynyl-substituted or alkenyl-substituted dibenzylammonium cations into the rings of crown ethers in the twin-axial [3]rotaxane, and then perform the CuAAC reaction or Olefin Metathesis to prepare a sort of novel circular twin-axial [5]catenane. Furthermore, their application in the molecular device will also be seeked. These investigations might open a new door for synthesizing more complicated interlocked molecules with well-defined structures and functions.

新型互锁分子的设计合成是一个具有挑战性的研究课题。该项目拟利用34冠10与二级铵阳离子形成1:2配合物以及葫芦[8]脲与萘酚和紫精阳离子形成1:1:1配合物的特性，设计合成两端都含有炔基的二级铵阳离子和紫精阳离子、以及2,6位衍生炔基的萘酚衍生物，制备以34冠10或葫芦[8]脲为轮、两个炔基二级铵阳离子或一个炔基萘酚和一个炔基紫精阳离子为双轴的准轮烷，进而与轴上含有叠氮基团的单轴准轮烷通过click反应制备轮轴分离的双轴杂[7]轮烷；与冠醚侧臂上的叠氮基反应制备冠醚环封端的双轴[3]轮烷，再通过二级铵阳离子与端基冠醚环的穿线、封端，制备轴轮一体的双轴杂[7]轮烷。在此基础上，通过双轴[3]轮烷上的四个冠醚环与双炔基或烯基二级铵阳离子穿线，进而通过click反应或烯烃复分解反应制备环状的双轴[5]索烃，探索它们在分子器件等方面的应用，为高效合成具有精确结构和功能的复杂互锁分子提供新的路线。

2016年的诺贝尔化学奖授予了三位从事分子机器研究的超分子化学家，从而将该领域的研究推向了一个新的高度。包括轮烷、索烃等在内的机械互锁分子是最重要的分子机器模型之一，对其深入的认知和功能的研究将有利于开发更广泛的分子机器，因此具有重要的理论意义。该项目主要研究成果包括三个方面：(1) 新型互锁分子的构筑：合成了一系列基于柱芳烃的[1]索烃和一对结构新颖的手性双子索烃。(2) 互锁分子的结构调控：构筑了一个具有准轮烷与轮烷双重结构特征的机械互锁分子，阐述了准轮烷与轮烷差异的新见解；构筑了一系列基于大环冠醚、环糊精、葫芦脲的具有光/热刺激响应的超分子组装体，实现了组装体形貌的可控转换。(3) 基于环糊精、冠醚等大环分子的超分子组装体的功能研究：设计合成了含有蒽基和三联吡啶基团的双冠醚，其与双稀土金属离子配位得到的超分子聚集体可以可逆地调控镧系金属发光；而Mn-卟啉和环糊精形成的超分子聚合物，是一种兼具荧光和磁共振双成像和具有靶向癌细胞的多功能造影剂。以上研究取得了一系列重要的阶段性成果，研究成果在Nature Commun.、 J. Am. Chem. Soc.、Chem. Commun.、Chem. Eur. J.、J. Mater. Chem. B等一些重要刊物上发表论文10篇，短期内他引67次。