有机模板协助构建的动态共价大环

Dynamic Covalent Macrocycles Constructed via Organic Templates

本文详细综述了有机模板协助而形成的动态共价大环。有机模板具有比金属离子更大的尺寸,因此可以诱导形成具有较大尺寸的大环结构。同时,有机模板结构具有多样性,可以通过化学反应进行按需修饰。可逆共价键有很多种,在模板诱导下形成大环结构的主要有三类:硫硫键、硼酸酯和希夫碱。硫硫键和硼酸酯的动态可逆性可以通过改变外界条件来开关。而希夫碱则可以通过还原转化为动力学稳定的共价键。因此,这类模板诱导而形成的热力学稳定大环可以转化为相应的动力学稳定大环,为大环主体的合成提供了一个新的途径。此外,动态共价大环的主客体键合模块还可以被用来构建更加复杂的超分子结构,例如轮烷和锁烃等。

Dynamic covalent macrocycles templated by organic molecules have been thoroughly reviewed. Organic templates have much larger sizes than metal ions, and therefore are suitable to template the formation of macrocycles with much larger cavity. Meanwhile, there are a variety of organic molecules, which may work as templates. Their structures can be tailor-made through various organic reactions. Out of many dynamic covalent bonds, there are three popular types which are often used to construct dynamic covalent macrocycles via template effect： disulfide, boronic ester, and imine. The reversibility of former two bonds can be switched on or off through changing the conditions. While imine bonds can be reduced to kinetically inert chemical bonds. Thus, the thermodynamically stable macrocycles in the presence of templates can be converted to the corresponding kinetically inert macrocycles, providing a new method for the preparation of macrocyclic hosts. In addition, the host-guest binding motifs based on dynamic covalent macrocycles can be used to construct more complex supramolecular architectures, for example, rotaxanes and catenanes.