作为一类新的晶型有机多孔材料，共价有机框架（COFs）具有比表面积大、孔道规整有序、骨架易于功能化等优点。这使得COFs材料在气体吸附、有机光电、荧光识别、多相催化等领域具有潜在的应用价值。然而，二维COFs由于其层与层之间堆积方式的不同会导致AA和AB型两种不同的堆积结构。目前还没有非常有效的技术手段能实现对两种堆积结构的准确表征。.作为表征多孔材料强大的工具之一，129Xe NMR技术已被广泛用于研究多孔材料的孔道结构。本项目拟通过选用不同电负性的直线型单体和三叉型单体，构筑出一系列二维COFs材料，拟采用超极化129Xe NMR以及129Xe 2D EXSY的分析手段探究这些COFs的孔结构，分析单体的电负性对二维COFs堆积结构的影响。该项目不仅能实现129Xe NMR技术对二维COFs堆积结构的表征，而且为构建高结晶性的二维COFs提供了相应的依据。

As a new type of organic crystalline material, covalent organic frameworks (COFs) have the advantages of large specific surface areas, long range ordered structures, and facilely-tailored skeletons. These merits make COFs material have potential applications in numerous fields, including gas adsorption, optoelectronics, fluorescent sensing, and heterogeneous catalysis. However, due to the different stacking fashion, 2D COFs display AA and AB stacking structure. So far, few methods can be utilized to distinguish these two stacking structures effectively. . As one of the powerful techniques for characterizing porous materials, 129Xe NMR technique has been widely used to study the structure of porous materials. In this project, through selecting the precursors with different electronegativity, a series of 2D COFs could be constructed. Then, hyperpolarized 129Xe NMR can be utilized to investigate the stacking structures of these 2D COFs. Meanwhile, the relationship between electronegativity of precursors and the stacking structure can be set up. This project not only detects the stacking structures of 2D COFs via 129Xe NMR, but also provides the valuable instruction for construction of high-crystalized 2D COFs.