Highly sensitive and selective fluorometric off–on K+ probe constructed via host–guest molecular recognition and aggregation-induced emission
作者:Xiaorui Wang、Jinming Hu、Tao Liu、Guoying Zhang、Shiyong Liu
DOI:10.1039/c2jm16510d
日期:——
In this work, we integrated the concept of aggregation-induced emission (AIE) with the specific supramolecular recognition between K+ ions and crown ether moieties to develop more effective fluorometric K+ probes. We synthesized a novel crown ether-functionalized tetraphenylethene (TPE) derivative, TPE-(B15C5)4, via the thiol-ene click reaction of thiol-derivatized TPE, TPE-(SH)4, with maleimide-functionalized benzo-15-crown-5 (B15C5). In TPE-(B15C5)4, the TPE core and four outer B15C5 moieties serve as the AIE-active motif and supramolecular K+-recognizing functionalities, respectively. TPE- (B15C5)4 molecularly dissolves in THF with negligible fluorescence emission. As we have envisaged, upon K+ addition, TPE-(B15C5)4 can be effectively induced to aggregate due to K+-mediated cross-linking via the formation of K+/B15C5 (1/2 molar ratio) molecular recognition complex in a sandwiched manner. This process is concomitantly accompanied with the turn-on of fluorescence emission via the AIE mechanism. Thus, TPE-(B15C5)4 can serve as highly sensitive and selective fluorometric offâon K+ probes.
在这项工作中,我们将聚集诱导发射(AIE)的概念与钾离子(K+)和冠醚基团之间的特定超分子识别相结合,开发了更有效的荧光钾探针。我们通过巯基修饰的四苯乙烯(TPE)TPE-(SH)4与功能化的苯并-15-冠-5(B15C5)进行硫醇-烯点击反应,合成了一种新颖的冠醚功能化四苯乙烯(TPE)衍生物TPE-(B15C5)4。在TPE-(B15C5)4中,TPE核心和四个外部的B15C5基团分别作为AIE活性基元和超分子K+识别功能。TPE-(B15C5)4在四氢呋喃(THF)中分子溶解,几乎没有荧光发射。如我们所设想的,添加K+后,TPE-(B15C5)4可以有效诱导聚集,这是由于通过形成K+/B15C5(1/2摩尔比)分子识别复合物而介导的K+交联。这一过程同时伴随着AIE机制下荧光发射的开启。因此,TPE-(B15C5)4可以作为高灵敏度和选择性的荧光开关钾探针。