A Fully Saturated Covalent\nOrganic Framework

We report the design and synthesis of the first aliphatic\ncovalent\norganic framework (COF), NUS-119, and its subsequent conversion to\nNUS-120, marking the first fully saturated COF. NUS-119 is built by\nimine-linkages exhibiting high crystallinity and porosity, achieved\nby using a Lewis acid as a reaction modulator to circumvent compatibility\nissues between the Brønsted acid and the strong basic monomer.\nThe structure was successfully solved using 3D microelectron diffraction\n(microED) techniques. NUS-119 and NUS-120 demonstrated remarkable\ncatalytic performance in base-catalyzed Knoevenagel condensation reactions,\nexhibiting high conversion rates, excellent size selectivity, and\ngood recyclability. This work advances the understanding of COF materials\nand paves the way for future research and applications.