Bisimidazole-Based Conjugated Polymers for Excellent Iodine Capture

We present a series of bisimidazole-based conjugated porous organic polymers (POPs) (BisImi-POP@1–6), which were formed by the CuI(I)–KOH/KOH-catalyzed cross-coupling reaction between the 2,2′-bisimidazole monomer and aryl halides. For iodine capture, the resultant POPs with a large number of imidazole N-heterocycle units in the skeletons can be used as effective adsorbents, which exhibit high iodine capture capacities of 9.50, 10.30, 4.83, 6.45, 3.57, and 3.93 g g–1 for BisImi-POP@1, BisImi-POP@2, BisImi-POP@3, BisImi-POP@4, BisImi-POP@5, and BisImi-POP@6, respectively. This is the second report of 2,2′-bisimidazole liquid complexes of the cationic backbone of the POPs and polyiodides as far as we know. Compared with previous solid iodine adsorbents, porous materials based on imidazole and its derivatives show unique properties when they are used as adsorbents for capturing radioactive iodine. This work studied the relationship between the iodine adsorption properties of imidazole-based polymers and the content of imidazole nitrogen heterocycles.