Construction of rigid amine-linked three-dimensional covalent organic frameworks for selectively capturing carbon dioxide

A highly rigid amine-linked 3D COF was constructed from two orthogonal building blocks (spirobifluorene and bicarbazole) through a post-synthetic chemical reduction. The rigid 3D framework decreased the conformational flexibility of the amine linkages, and thus showed a fully preserved crystallinity and porosity. The amine moieties in the 3D COF afforded abundant chemisorptive sites for selectively capturing CO2.