Regulating Both In‐Plane and Out‐Of‐Plane Supramolecular Interactions in COFs for Simultaneously Enhanced Crystallinity and Stability

The demand for high-performance applications of covalent organic frameworks (COFs) under harsh conditions drives the need for reaching both outstanding crystallinity and high stability, while these two properties necessitate contradictory structural features and are thus challenging to achieve simultaneously. We herein report a multidimensional supramolecular approach to manipulating both crystallinity and stability of COFs by harnessing in-plane and out-of-plane interactions with greatly enhanced performance in applications. The introduction of triple three-center hydrogen bonds into the linkage enhances in-plane local rigidity and planarity, while embedding electron-withdrawing heteroatoms into the linker mitigates out-of-plane electrostatic repulsion. The integration of the two structural features into a single COF results in profoundly enhanced interlayer π-π stacking interactions, ultimately providing considerably higher crystallinity and stability than those of control COFs, as well as significantly improved performance under harsh conditions, as exemplified by palladium separation from simulated high-level liquid waste. This work establishes a hybrid supramolecular approach to improving both crystallinity and stability of COFs toward prominent applications.