The efficient capture of radioactive iodine and sensitive detection of picric acid are very important to environmental protection. Herein, we synthesized two new flexible 4,4′-thiodianiline (TDA)-based covalent organic frameworks (TTDA and HTDA) by using simple Schiff-base polycondensation reactions with flexible 4,4′-thiodianiline (TDA) and 2,4,6-tris(4-formylphenoxy)-1,3,5-triazine (TPT − 3 − CHO) and hexa(4-formyl-phenoxy)cyclotriphosphazene (NOP − 6 − CHO). The flexible TDA-based COFs are porous, crystalline, and show high thermal stability and good chemical stability. Due to the high content of heteroatoms, abundant aromatic rings, and orderly network, it is conducive to electron transfer, the as-prepared flexible TDA-based COFs show outstanding dual properties of iodine adsorption and fluorescence sensing. The maximum iodine capacities of TTDA and HTDA are as high as 3.34 and 4.38 g g, respectively. The flexible TDA-based COFs can be used for sensing picric acid with low limits of detection (LODs) of 1.25 × 10 and 1.67 × 10 mol L and high quenching constants (K) of 6.00 × 10 and 4.88 × 10 L mol, respectively.

中文翻译：

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以苯硫醚为连接基的柔性共价有机骨架的构建，用于吸附碘和荧光传感苦味酸

放射性碘的高效捕获和苦味酸的灵敏检测对于环境保护非常重要。在此，我们通过使用柔性4,4'-硫代苯胺（TDA）和2,4，通过简单的席夫碱缩聚反应合成了两种新型柔性4,4'-硫代苯胺（TDA）基共价有机框架（TTDA和HTDA）。 6-三(4-甲酰基苯氧基)-1,3,5-三嗪(TPT - 3 - CHO)和六(4-甲酰基苯氧基)环三磷腈(NOP - 6 - CHO)。基于TDA的柔性COF是多孔的、结晶的，并表现出高热稳定性和良好的化学稳定性。由于杂原子含量高、芳环丰富、网络有序，有利于电子转移，所制备的柔性TDA基COF表现出突出的碘吸附和荧光传感双重性能。 TTDA和HTDA的最大碘容量分别高达3.34和4.38 g·g。基于 TDA 的柔性 COF 可用于检测苦味酸，检测限 (LOD) 分别为 1.25 × 10 和 1.67 × 10 mol·L，淬灭常数 (K) 分别为 6.00 × 10 和 4.88 × 10 L mol 。