Synthesis of secondary amine‐based fluorescent porous organic polymers via Friedel–Crafts polymerization reaction for adsorbing and fluorescent sensing iodine

Abstract

Abstract We present the preparation and characterization of a novel class of secondary amine‐based porous organic polymers (POPs: TDPA and TTPBTA), and their iodine adsorption, fluorescence sensing properties for the first time. Two secondary amine‐based POPs were synthetized by Friedel−Crafts polymerization reaction catalyzed via methylsulfonic acid with yields of 22.51 and 54.44%. The thermal stability of resulting POPs run up to above 268 and 568°C, and their BET specific surface areas are 56.5 and 2.49 m 2 g −1 , respectively. Their iodine adsorption and fluorescent sensing properties are comparable to that of triphenylamine (TPA)‐based (tertiary amine) POPs. The resulting POPs display excellent sorption abilities to iodine molecules with the iodine adsorption capacity of about 3.93 and 1.64 g g −1 . Adsorbed iodine is easily desorbed by heating or washing with organic solvents, which make them reusable. They can also adsorb iodine from cyclohexane solution. Moreover, the POPs possess excellent fluorescent sensing property for I 2 with Ksv of 1.85 × 10 4 and 6.56 × 10 4 L mol −1 , as well as the limits of detection (LODs) of 1.62 × 10 −11 and 6.86 × 10 −12 mol L −1 . The performance of adsorbing and fluorescence sensing iodine can be explained by electron transfer mechanism.