基于三唑并噻二唑-香豆素体系的高选择性识别硫化氢比率型荧光探针的合成及应用

Synthesis and Application of Triazolothiadiazole-Coumarin Based Ratiometric Fluorescent Probes for Highly Selective Detection of HS

为了有针对性地高选择荧光识别硫化氢(H2S),以香豆素为核心组块与三唑并噻二唑芳香稠并杂环拼接,设计合成了3个比率型荧光探针4a~4c,借助红外光谱(IR)、核磁共振(NMR)和高分辨质谱(HRMS)等对其进行了结构表征.通过荧光光谱法,研究发现3个探针均具有优良的荧光性能,说明探针分子整体结构设计合理,均表现出较高的荧光量子产率(0.6752, 0.6639, 0.6128)和大的斯托克斯位移(138, 131, 128 nm). 3个探针对H2S均具有高选择和高灵敏性识别,其检测限(LOD)分别为0.19, 0.21, 0.25μmol·L^(-1).其中4a显示了最优的效果,说明分子中苯环4位斥电基团的存在使共轭体系电子密度升高,有利于探针性能的优化.此外探针与H_(2)S作用后,颜色从无色变为深黄色,可以实现H2S的"裸眼检测".探针4a~4c成功应用于实际水样中H2S的定性定量检测.

Three triazolothiadiazole-coumarin based ratiometric fluorescent probes(4a~4c) for detection of H2S were designed and synthesized. Their structures were confirmed by IR, NMR and HRMS. Through fluorescence spectra, the probes expressed excellent fluorescent properties, which indicates that the design of the molecular structure was rational. The three probes all displayed highly quantum yields(0.6752, 0.6639, 0.6128), large Stokes shift(138, 131, 128 nm).They all exhibited high selectivity and sensitivity against H2S. The limit of detection were 0.19, 0.21 and 0.25 μmol·L^(-1) respectively. Especially, probe 4a has the optimum efficiency,this result shows that the electron-donating group at 4-position of benzene is in favor of the optimization of fluorescent properties, owing to the accretion of electron density of the conjugated system. Besides, the three probes were all able to sense H_(2)S by "naked-eye" according to the change in color from colorless to deep yellow. The probes can be applied to recognize H2S in actual water samples qualitatively and quantitatively.