A robust indium-porphyrin framework for CO₂ capture and chemical transformation

An indium based metal-porphyrinic framework, denoted NUPF-3, was prepared based on a new amido-decorated porphyrin ligand. NUPF-3 possesses a rarely seen 4-fold interpenetrated pts framework with segmented pores and dense metalloporphyrin central sites. The structure can retain its crystallinity in commonly used solvents, as well as acidic/alkaline solutions with pH ranging from 1 to 12 for 48 h, exhibiting high chemical stability. Meanwhile, thermal analysis reveals that NUPF-3 possesses relatively high thermal stability. Owing to the presence of amido groups, structural interpenetration and a charged framework, NUPF-3 exhibits relatively high CO₂ uptake. Moreover, NUPF-3 could be used as a good heterogeneous catalyst for cycloaddition of CO₂ and epoxides, under relatively mild conditions, with good recyclability.