Stable and microporous covalent organic frameworks via weak interactions for gas uptake

Covalent organic frameworks are a new class of porous organic polymers that combine excellent stability and well-defined structures. We have designed and constructed two imine COFs (COF-OH and COF-F) with micro-porosity and high stability through the Schiff base reaction. The high porosity and stability of COF-OH are due to intramolecular hydrogen bonding between hydroxyl units with nitrogen atoms in the imine linkage. The fluorine-based COF (COF-F) shows high porosity and stability due to substantial energetic stabilization in the face-to-face stacking interaction on the wall. The COFs also demonstrate high porosity as active platforms for iodine uptake up to 5.71 g g(-1) and carbon dioxide uptake up to 3.92 mmol g(-1)via weak interactions resulting from high porosity and linkages (N atoms) to walls (N, F, and O atoms) in the aromatic skeleton.