Design, Synthesis, and Applications of Mesoporous Covalent Organic Frameworks

Covalent organic frameworks (COFs) are highly or-dered and permanently porous organic polymers that can be classified as two-dimensional or three-dimensional. Their tunable design and crystalline or-der endow a range of pore sizes, shapes, functions, and applications that differentiate them from other polymers. The COF pore sizes and shapes rely on the geometry of the monomers and dynamic covalent chemistry, while the stacking of the sheets relies on noncovalent interactions. Their tunability allows for post-modification or the incorporation of additional functional groups for the reinforcement by various noncovalent interactions. The limits of mesoporous COFs are still being investigated, with the design rules continuing to evolve. Here we report a compre-hensive review of mesoporous COFs, explore strategies for large pore reinforcement, highlight structural design and features, elucidate their various functions and applications, discuss fundamental challenges faced that need to be addressed, and predict future directions.