Fig. 2.

COFs with different chemical stability a Construction of the binary, ternary, and quaternary COFs and their stacking modes. Adapted with permission [81]. Copyright © 2018, American Chemical Society. b Schematic representation of the rigid and distorted HBC nodes and their incorporation in boronate ester COFs to obtain Marta-COF-1 with a wavy and highly complementary structure that guided the stacking of COF layers. Adapted with permission [79]. Copyright © 2019, American Chemical Society. c Normal framework without alkyl groups, in which the structure would collapse after being exposed to harsh environments, and hydrophobic framework with alkyl groups, in which the architecture could withstand harsh environments due to the protection of hydrophobic groups. Adapted with permission [74]. Copyright © 2020 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim