Construction of dual-functional nitrogen-enriched fluorescent porous organic polymers for detecting m-dinitrobenzene, picric acid and capturing iodine

[Display omitted] •Two nitrogen-rich POPs were constructed via nucleophilic substitution reactions.•HBP and TBP exhibit high sensitivity to m-dinitrobenzene and picric acid.•HBP and TBP exhibit excellent volatile iodine adsorption. Two novel nitrogen-enriched porous organic polymers (POPs), HBP and TBP, were constructed via nucleophilic substitution reactions with high nitrogen contents up to 24.91% and 32.92% for sensing to nitroaromatic compounds (NACs) and adsorbing iodine. They were all systematically characterized by solid-state 13C NMR, FT-IR, elemental analysis, solid-state UV–Vis, and other material analysis methods. The experimental data proved that both POPs possess high chemical and thermal stability, excellent fluorescence performance, and porous properties with Brunauer–Emmett–Teller (BET) specific surface areas of 32.88 and 68.00 m2 g−1. The two POPs have dual functions of fluorescence sensing and adsorption. On the one hand, due to their excellent conjugated properties and nitrogen-enriched structures, HBP and TBP exhibited incredibly high sensitivity to m-dinitrobenzene (m-DNB) and picric acid (PA) with KSV values of 2.57 × 105 and 4.93 × 104 L mol−1 and limits of detection of 1.17 × 10-11 and 6.08 × 10-11 mol L-1, respectively. On the other hand, owing to the plenty of nitrogen affinity sites, they exhibited excellent volatile iodine adsorption with 2.23 and 2.66 g g−1, respectively.