Flexible Oxygen‐Bridged Porous Organic Polymers for Adsorping and Fluorescence Sensing Iodine and the Formation of Liquid Complexes of POPs‐(Poly)Iodide Anions

Abstract

Abstract Three flexible oxygen‐bridged porous organic polymers (TPG, HCCPA, and HPG) have been synthesized by nucleophilic substitution polymerization reactions. The three POPs display efficient and reversible adsorption of radioactive I 2 in vapor and solution. In iodine vapor at 350 K, the maximum iodine adsorption capacities of TPG, HCCPA, and HPG are 5.29, 4.08, and 1.63 g g −1 , respectively. The strong affinities for I 2 are mainly due to the charge transfer of the POPs to iodine. Interestingly, with the decrease of iodine adsorption, charge transfer complexes of TPG, HCCPA, and HPG exhibit liquid, semi‐solid, and solid states, respectively. Furthermore, the three POPs have been found to fluorescently detect molecular iodine. The S–V quenching constants of TPG, HCCPA, and HPG are 2.01 × 10 4 , 1.14 × 10 4 , and 1.44 × 10 3 L mol −1 , respectively. Their sensitivities decrease with the decrease of iodine adsorption. Pleasingly, HCCPA can sense molecular iodine by fluorescence in aqueous solution. Most probably, this is the first example of POPs used for fluorescent sensing molecular iodine in aqueous solution. Both TPG and HCCPA act as efficient adsorbents and chemical sensors of iodine.