Pyrazine-Based Covalent Organic Frameworks for Effective Iodine and Carbon Dioxide Capture

Covalent organic frameworks (COFs) possess good porosity, uniform channels, and tunable skeletons, as well as excellent stability, which are well-suited for gas adsorption. In this study, we developed two pyrazine-based COFs, namely, TFPPz–MPA–COF and TFPPz–BD(OMe)₂–COF, by condensation reaction of C₄ and C₂ axisymmetric monomers. Both COFs exhibited good crystallinity, well-defined pore structures, and outstanding thermal and chemical stability. TFPPz–MPA–COF and TFPPz–BD(OMe)₂–COF demonstrated high iodine adsorption capabilities of up to 5.41 and 5.18 g g^–1 in iodine vapor, and 95.42 and 98.04 mg g^–1 in <i>n</i>-hexane, respectively. In addition, TFPPz–MPA–COF and TFPPz–BD(OMe)₂–COF exhibited good CO₂ uptake capacities of 1.48 and 1.34 mmol g^–1 at 273 K, respectively.