基于金属有机分子笼的机械键的可控构筑

Mechanical linkage such as interpenetrate,interlock play a crucial role not only in the assembly of biomacrolecules in natural system, but also in preparing intriguing topologies and molecular machines. Synthetic chemists have utilized covalent bond linking units to construct mechanical bonds, however this traditional method seems inefficient and inconvenient, and the new-formed mechanical bonds cannot transform next. Using coordination bond linking metallacages to construct mechanical bonds can lead to more complex molecules. So far, only very few examples in which metallacages have been used to construct mechanical bonds have been reported, and their assembly process still seems obscure, moreover,construction of rotaxane based on metallacages has not been reported. Our program intend to use controllable and reversible coordination bonds to prepare precusor for mechanical interlocking,discrete cages, then utilize the new-formed cages to controllable construct mechanical bonds.Firstly, we intend to use flexible tripodal ligands and 2-coordinated metal ions to assemble cage molecules which have suitable cavity and windows; secondly, we want to controllable synthesize catenanes which contain multiple or single mechanical bonds based on these cage molecules; finally, we try to prepare the rotaxane based on metallacage.We also wish to adjust the process of construction of mechanical bonds based on cages through changing their assembly conditions and understand them ultimately.

机械键如穿插、互锁不仅普遍存在于生物体中，还是拓扑结构复杂分子以及分子机器的重要组成部分。尽管合成化学家已经通过稳定的共价键连接单元来构筑机械键，然而该传统的方法低效、繁琐，形成的机械键难以转变。而利用配位键连接的金属有机分子笼来构筑机械键能更高效地合成更复杂的分子。到目前为止，利用金属有机分子笼来构筑机械键的报道很少，其具体的自组装过程也模糊不清，基于分子笼的轮烷类化合物的合成研究更是未见报道。本项目拟采用可控的、可逆的配位键来合成构筑机械键的前躯体即孤立的金属有机分子笼，并利用合成的分子笼来可控的构筑机械键：首先利用灵活的三齿配体与二配位的金属离子来自组装具有合适空腔和窗口的分子笼，然后利用合成的分子笼在合适的条件下可控构筑含单重或多重机械键的索烃类化合物，最后尝试合成基于分子笼的轮烷类化合物。期望通过自组装条件的改变来调节基于分子笼的机械键构筑过程,并探索其自组装规律。

本项目合成了系列新颖的半刚性的多齿配体，并利用这些半刚性配体合成了多个金属有机大环和金属有机纳米笼，在外界刺激的诱导下还实现了这些大环、纳米笼的机械键的可控构筑。还合成了系列含多个纳米笼的配位聚合物，并实现了其可控应用。