Synthesis And Properties Research Of Near-Infrared Fluorescent Probes Based On Dicyanomethylene-benzopyran Chromophores

Fluorescent detection has attracted much attention in recent years because of its simplicity, low cost, high sensitivity and capability of real-time detection. Near-infrared (NIR,650-900 nm) fluorescent detection has unique advantages for biological imaging applications, because they produce minimum interference background fluorescence, cause less damage to biological samples and penetrate much deeper into tissues than UV and visible light.In this thesis, two near-infrared fluorescent probes have been designed and synthesized, and their sensing properties and potential applications were studied. The main research is as follows:We have presented a new promising NIR fluorescent probe for biothiols.This probe is based on a conjugated dicyanomethylene-benzopyran (DCMB) structure and an acrylate moiety as the reaction site. This probe shows rapid response, high sensitivity and selectivity for biothiols (Cys, Hey and GSH). Meanwhile, it shows distinct color changes and significant NIR fluorescence turn-on responses. The detection limit of probe for Cys was found to be 81 nM. In addition, this probe can be used for imaging of biothiols in living cells, indicating that this probe shows great potential for applications in biological samplesThiophenols are highly toxic, so it is important to develop probes for rapid, selective and sensitive detection of thiophenols both in environmental and biological science. Despite NIR fluorescent detection holds the appealing advantages, no NIR fluorescent probes have yet been reported for thiophenols to date. We herein developed a dicyanomethylene-benzopyran (DCMB)-based NIR fluorescent probe for thiophenols. Using the unique chemical properties of thiophenols which can cleave sulfonamide selectively under mild conditions. This probe shows rapid response, high selectivity and sensitivity for thiophenols with remarkable large Stokes shift and significant NIR fluorescent turn-on responses. This new NIR fluorescent probe can detect thiophenol quantitatively in real water samples. Moreover, it can be used for fluorescent imaging of thiophenol in living cells, which demomstrates its great potential for applications in environmental and biological science.