高选择性比色识别碘离子的氨基硫脲类阴离子受体

设计合成了一系列基于氨基硫脲的阴离子受体（M1～M4）.此类受体以氨基硫脲基团为识别位点,以硝基苯基为信号报告基团,其中受体M1和M3可在乙腈溶液中高选择性的比色识别碘离子.在受体M1或M3的乙腈溶液中加入I^–时,溶液的颜色由浅红色变成无色,而加入其他离子如F^–,Cl^–,Br^–,AcO^–,HSO4^–,H2PO4^–,ClO4^–等阴离子时,受体溶液不会褪色.通过紫外滴定和核磁滴定等方法研究了受体选择性比色识别碘离子的机理.结果表明,受体通过其氨基硫脲基团上的三个NH质子与碘离子形成的三重氢键选择性的结合碘离子.在此过程中,受体构型发生转变,从而导致了颜色变化,产生了比色识别的效果.此类阴离子受体具有合成方法简便,产率高,识别效果好等优点.

Highly selective colorimetric iodide receptors based on thiosemicarbazides

A series of simple and highly selective colorimetric iodide receptors （M1-M4） bearing thiosemicarbazide moiety as recognition site and nitro moiety as signal group were synthesized. In CH3CN solutions, sensors M1 and M3 showed colorimetric single selectivity for V. When V was added to their solutions, dramatic color changes from pink to colorlessness were observed. Yet other anions such as F^-, Cl^-, Br^-, AcO^-, HSO4^-, H2PO4^-and ClO4^- couldn＇t cause any distinct color change. The recognition mechanism of the receptor toward various anions was evaluated in CH3CN solution by UV-vis and ^1H NMR. The receptors selectively recognize iodide through the three hydrogen bonds formed by the NH groups of the thiosemicarbazide moiety. When these hydrogen bonds formed, the conformation of the receptor changed, which led to the color changes of receptor. These kinds of receptors not only easy to synthesized but have high selectivity and affinity for iodide.