SO₂ Capture Using Porous Organic Cages

Abstract

We report the first experimental investigation of porous organic cages (POCs) for the demanding challenge of SO₂ capture. Three structurally related N-containing cage molecular materials were studied. An imine-functionalized POC (CC3) showed modest and reversible SO₂ capture, while a secondary-amine POC (RCC3) exhibited high but irreversible SO₂ capture. A tertiary amine POC (6FT-RCC3) demonstrated very high SO₂ capture (13.78 mmol g^-1 ; 16.4 SO₂ 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.