Hierarchical porous organic hyper-cross-linked polymers containing phthalazinone and carbazole moieties for gas uptake and fluorescence properties

[Display omitted] •Phthalazinone and carbazole groups were employed in construct hierarchical porous organic polymers by two methods.•These porous organic polymers exhibited high BET surface area, CO2 uptake capacity and selectivity.•The fluorescent polymers displayed high sensitivity and selectivity for detecting nitroaromatic analytes. Based on rigid and twisted heterocyclic phthalazinone unit as the core skeleton, novel hierarchical porous carbazole-containing porous organic polymers (PCMOPs) were successfully constructed through Friedel-Crafts reaction (PCMOP-Hs) and oxidation coupling reaction (PCMOP-Os), respectively, with anhydrous FeCl3 as catalyst. The structures of resultant PCMOPs were characterized by FT-IR, 13C CP-MAS NMR and WXRD. PCMOP-Hs displayed higher BET surface area (660–675 m2 g−1), CO2 uptake capacity (11.8–12.1 wt%, 273 K, 1 bar) and CO2/N2 selectivity (up to 78.46, IAST) than those of PCMOP-Os, respectively. Even though, PCMOP-Os both displayed high sensitivity and selectivity with the fluorescent quenching rate value up to 83% for 2,4-dinitrotoluene (DNT) and 70% for nitrobenzene (NB) in low concentration (10−2 mol/L). The properties along with large-scale and low-cost preparation make these hierarchical POPs potential candidates for gas storage and separation as well as fluorescence detection of explosives application.