SO₂ Capture Using Porous Organic Cages

We report the first experimental investigation of porous organic cages (POCs) for the demanding challenge of SO 2 capture. Three structurally related N‐containing cage molecular materials were studied. An imine‐functionalized POC (CC3) showed modest and reversible SO 2 capture, while a secondary‐amine POC (RCC3) exhibited high but irreversible SO 2 capture. A tertiary amine POC (6FT‐RCC3) demonstrated very high SO 2 capture (13.78 mmol g −1 ; 16.4 SO 2 molecules per cage) combined with excellent reversibility for at least 50 adsorption–desorption cycles. The adsorption behavior was investigated by FTIR spectroscopy, 13 C CP‐MAS NMR experiments, and computational calculations.