Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing 100871, China.
J Am Chem Soc. 2023 May 24;145(20):11276-11281. doi: 10.1021/jacs.3c01729. Epub 2023 May 11.
Dimensional isomers, defined in reticular chemistry as frameworks consisting of identical molecular building blocks but extended in two or three dimensions (2D or 3D), are an important type of framework isomers that have never been isolated. Herein, we report the crystallization of dimensional isomers in covalent organic frameworks (COFs) for the first time. By polymerization of the same molecular building blocks at different temperatures, both 2D and 3D COFs were successfully constructed due to the temperature-induced conformational changes of precursors from planar to tetrahedral. In addition, the non-fluorescent 2D COF can be gradually converted into the fluorescent 3D COF by increasing the temperature under solvothermal conditions. Therefore, it is reasonable to crystallize the dimensional isomers of reticular materials by controlling the conformation of molecular building blocks, and more examples can be expected. Since the obtained dimensional isomers show different properties and functions, this work will definitely motivate us to design reticular materials for target applications in the future.
维构象异构体，在网状化学中被定义为由相同的分子构建块组成但在二维或三维方向上延伸的框架，是从未被分离出来的一种重要的框架异构体。在此，我们首次报道了在共价有机骨架（COFs）中维构象异构体的结晶。通过在不同温度下聚合相同的分子构建块，由于前体从平面到四面体的温度诱导构象变化，成功构建了 2D 和 3D COFs。此外，在溶剂热条件下升高温度，非荧光性的 2D COF 可以逐渐转化为荧光性的 3D COF。因此，通过控制分子构建块的构象来结晶网状材料的维构象异构体是合理的，预计还会有更多的例子。由于所得到的维构象异构体表现出不同的性质和功能，这项工作必将促使我们在未来设计针对特定应用的网状材料。
