Pillararene-embedded covalent organic polymers for photocatalysis and beyond

Porous covalent organic polymers (COPs) have demonstrated significant potential in photocatalysis owing to their tunable properties. The integration of catalytic units into COPs can balance structural integrity and adaptability, thereby enhancing materials' photocatalytic activity. The development of new catalytically active centers in COPs is considered an effective approach to broaden the scope of photocatalysis. Macrocycles with cavities, including crown ethers, cyclodextrins, calixarenes, phthalocyanines, porphyrins, and pillararenes, are capable of substrate-specific recognition and selective guest binding, thus improving the efficiency of photocatalysts. The incorporation of non-planar macrocycles, such as crown ethers and pillararenes, into COPs leverages the advantages of both covalent and supramolecular chemistry to enable stable and efficient photocatalysis. This review highlights the recent advancements in pillararene-based COPs as exemplary photosensitizers, offering insights into their structural features and potential applications in photocatalysis.