Macrocycle-embedded metal-covalent organic frameworks for catalysis: A bridge between covalent and non-covalent functional frameworks

With the advancement of functional porous materials, macrocycles that possess well-defined cavities and supramolecular functions have become emerging materials for applications in various fields. However, the aggregation of these macrocycles can lead to the coverage or loss of their active sites, which presents a significant obstacle in their functional applications. Covalent organic frameworks (COFs) comprise designable units and ordered structures that ensure the non-close packing of functional segments within the skeleton. Therefore, incorporating macrocycles into COFs through covalent or non-covalent strategies has proven to be a successful approach to enhancing macrocycle activity. Additionally, the inclusion of macrocycles provides additional active sites, enhancing the overall functionality of the skeleton through post-modification. Specifically, macrocycle-based COFs with metal participation (M−MCOFs) combine the advantages of organic/inorganic, polymeric, and supramolecular materials. Consequently, M−MCOFs hold great potential in energy storage, adsorption, separation, sensing, catalysis, etc. This review focuses on the concepts, synthesis, and performance of M−MCOFs, with a specific emphasis on their latest advancements in catalysis. Furthermore, we discuss the challenges and opportunities in this emerging field, emphasizing the importance of environmental sustainability and energy efficiency.