Chemically Stable Tetrazine-Based Porous Organic Cages with Post-Synthetic Modification via iEDDA Reactions

Porous organic cages (POCs) have emerged as promising porous materials for a wide range of applications. However, their development is often limited by insufficient chemical stability and challenges in systematically functionization. Herein, we reported the design and synthesis of a tetrazine-based POC (TC1) with rigid tetra-hedral structures via a one-pot nucleophilic aromatic substitution reaction. TC1 exhibits high porosity, with a BET surface area at 1157 m2/g, and remarkable chemically stability, retaining its integrity even in concentrated acid. Its well-defined cavity size and electron-deficient environment enable effective SF6/N2 separation, as con-firmed by dynamic breakthrough experiments. Post-synthetic modification of TC1 via inverse electron-demand Diels-Alder (iEDDA) reactions yielded two functionalized cages (TC2 and TC3), which maintain good porosi-ty and display further enhanced chemical stability over a broad pH range (-1 to 15). Furthermore, cage-based networked materials (TC1-P1 and TC1-P2) were successfully constructed through the iEDDA polymerization using TC1 as building unit, resulting in tunable porous frameworks with improved CO2/N2 selectivity.