Reticular Synthesis of Covalent Organic Frameworks with kgd-v Topology and Trirhombic Pores

Two-dimensional (2D) covalent organic frameworks (COFs) with designable pore structures can be synthesized under the guidance of topology diagrams. Among the five existing edge-transitive topological nets, kgd topology is considered a fine candidate for constructing COFs with ultramicropores. However, all of the reported COFs with kgd topology need the use of C₆-symmetric monomers, which are limited in compound type and difficult to synthesize. Here, we first develop a new approach to construct 2D COFs (clv-COFs) with a similar geometrical shape of kgd topology, named kgd-v topology, through the combination of C_2v- and C₃-symmetric monomers. The size of micropores in these clv-COFs is consistent with the rhombic pores in kgd topology and can be easily tuned by varying the length of C_2v- and C₃-symmetric monomers. These clv-COFs exhibit excellent atmospheric water harvesting (AWH) ability due to regular small micropores. An efficient water harvester based on clv-COF-1 can produce 1.73 L kg^-1 day^-1 at 45% relative humidity under solar illumination. Our approach enriches the reticular chemistry and can facilitate the research of COF-based AWH systems.