Synergizing Mechanochemistry and Multicomponent Reactions for Sustainable COF Synthesis

Mechanochemistry has emerged as a cornerstone of sustainable synthesis, providing an energy-efficient, solvent-free alternative to conventional solution-phase methodologies while minimizing environmental impact. Despite increasing application of mechanochemical approaches for preparing diverse organic compounds, the extension of these strategies to the synthesis of covalent organic frameworks (COFs) is limited up to now. Notably, the mechanochemical synthesis of multicomponent reaction-derived COFs (MCR-COFs) has not been previously reported. Herein, we demonstrate solvent-free mechanosynthesis of MCR-COFs through a three-component Povarov cascade reaction, efficiently combining aldehydes, amines, and phenylacetylenes with tert-butyl peroxybenzoate as the unique oxidant under one-pot ball-milling conditions. The resulting frameworks exhibit exceptional structural regularity, manifested by high crystallinity and well-defined permanent porosity with surface areas reaching 1371.6 m²/g. Intriguingly, the mechanosynthesized MCR-COFs exhibit a different stacking mode from the traditional solvothermal counterparts. Remarkably, these mechanosynthesized COFs can be applied to solvent-free mechanochemical reaction for the first time. This work establishes a paradigm shift in COF synthesis by merging the sustainability benefits of mechanochemistry with the accuracy of three-component cascade synthesis, while simultaneously advancing the catalytic applications of COF materials through mechanochemistry.