The Synthesis of Covalent Triazine‐Based Frameworks via Friedel–Crafts Reactions of Cyanuric Chloride with Thienyl and Carbazolyl Derivatives for Fluorescence Sensing to Picric Acid, Iodine and Capturing Iodine

Abstract A multifunctional thiophene‐based covalent triazine framework (TTPATTh) with triphenylamine as core is synthesized by Friedel–Crafts reaction of cyanuric chloride with thienyl derivative for the first time. The yield of TTPATTh (99.59%) is far higher than that of the carbazole‐based CTF (TTPATCz, 47.03%). TTPATTh and TTPATCz possess high BET surface areas with 1235 and 2501 m 2 g –1 as well as high pore volumes with 1.60 and 2.23 cm 3 g –1 , respectively. TTPATTh and TTPATCz have high thermal stability with high thermal decomposition temperatures of 514 and 598 °C in nitrogen atmosphere. With the introduction of triazine rings, the fluorescence sensing sensitivities of TTPATTh and TTPATCz to picric acid and iodine are improved significantly. Especially for TTPATTh, the K sv values reach 5.95 × 10 5 and 1.61 × 10 4 L mol –1 , and LODs reach 1.02 × 10 –12 and 1.86 × 10 –12 mol L –1 . To the best of the knowledge, this is the most sensitive value among thiophene‐based porous organic polymers to PA and I 2 . Furthermore, TTPATTh and TTPATCz can also adsorb iodine in vapor phase, cyclohexane solution and aqueous solution, and release iodine by heating or in ethanol solution. The efficiency of controlling the release of iodine is higher than that in ethanol.