biostudies-literatureNguyen HLDefense Advanced Research Projects AgencyStudienstiftung des Deutschen VolkesUniversity of California BerkeleyDeutsche Akademie der Naturforscher Leopoldina - Nationale Akademie der Wissenschaften926-932https://www.ebi.ac.uk/biostudies/studies/S-EPMC9336147biostudies-literatureUnknown8(7)We report a postsynthetic strategy and its implementation to make covalent organic frameworks (COFs) with irreversible hydrazide linkages. This involved the synthesis of three 2D and 3D hydrazine-linked frameworks and their partial oxidation. The linkage synthesis and functional group transformation-hydrazine and hydrazide-were evidenced by ¹⁵N multi-CP-MAS NMR. In addition, the isothermal water uptake profiles of these frameworks were studied, leading to the discovery of one hydrazine-hydrazide-linked COF suitable for water harvesting from air in arid conditions. This COF displayed characteristic S-shaped water sorption profiles, a steep pore-filling step below 18% relative humidity at 25 °C, and a total uptake capacity of 0.45 g g^-1. We found that even small changesACS central scienceHydrazine-Hydrazide-Linked Covalent Organic Frameworks for Water Harvesting.PMC9336147LPDS 2019-02HR0011-21-C-0020Hanikel NMockel AGropp CLund ANguyen HLYaghi OMfalseHydrazine-Hydrazide-Linked Covalent Organic Frameworks for Water Harvesting.We report a postsynthetic strategy and its implementation to make covalent organic frameworks (COFs) with irreversible hydrazide linkages. This involved the synthesis of three 2D and 3D hydrazine-linked frameworks and their partial oxidation. The linkage synthesis and functional group transformation-hydrazine and hydrazide-were evidenced by ¹⁵N multi-CP-MAS NMR. In addition, the isothermal water uptake profiles of these frameworks were studied, leading to the discovery of one hydrazine-hydrazide-linked COF suitable for water harvesting from air in arid conditions. This COF displayed characteristic S-shaped water sorption profiles, a steep pore-filling step below 18% relative humidity at 25 °C, and a total uptake capacity of 0.45 g g^-1. We found that even small changes2022-01-01T00:00:00Z2022 Jul2025-04-18T18:09:13.521Z2025-04-07T05:40:21.037ZS-EPMC93361473591235310.1021/acscentsci.2c00398