Synthesis of New-Generation of 1,4-Dihydropyridine-Linked Covalent Organic Framework

We report 1,4-dihydropyridine covalent organic framework (DHP-COF) constructed through 1,4-dihydropyridine linkage via the Hantzsch pyridine synthesis. The synthesis is carried out under mild conditions and produces high yield of porous material. The 1,4-dihydropyridinelinked COF-3 (DHP-COF-3) has a high crystalline hexagonal structure with an ABC stacking pattern in three layers. The 1,4-dihydropyridine linkage introduces both hydrogen-bond acceptor sites and hydrophobic domains within the framework, which provide areas for electrostatic and hydrophobic interactions with per-and poly-fluoroalkyl substances (PFAS). DHP-COF-3 removed PFOS and PFOA from drinking water near quantitatively with a starting concentration of 2.4 μg L-¹, and it can be reused over several absorption cycles efficiently.