A Mechanochemical Imine Exchange Route to 2D Imine-Linked Covalent Organic Frameworks

The mechanosynthesis of imine-linked covalent organic frameworks (COFs) has garnered significant attention. Nevertheless, existing reports predominantly rely on imine condensation and produce hexagonal frameworks. Here, we introduce the imine exchange reaction as a powerful synthetic toolkit for COF mechanochemistry, wherein four 2D imine-linked COFs featuring diverse topologies ( kgm, sql, and hcb ) were synthesized within an hour under ambient conditions. The resultant COFs exhibit high crystallinity and surface areas (860–1380 m 2 /g), far exceeding those (20–505 m 2 /g) made by direct condensation. Notably, an aggregation-induced emission (AIE)-based COF was obtained in just 30 min, whereas it remained inaccessible via mechanochemical direct condensation. Time-resolved 1 H NMR studies in a mechanochemical model reaction reveal much slower imine exchange kinetics than direct condensation, which facilitates effective error correction during COF growth and ultimately yields higher-quality frameworks. This work establishes a rapid, green, and generalizable route to high-quality imine-linked COFs superior to those produced by direct condensation.