Synthesis And Properties Of Three Small-molecule H₂S_n,Cys,CN^- Fluorescent Probes

As one of the important tools of fluorescence analysis,fluorescent probe has many advantages such as low cost,high signal-to-noise ratio,high sensitivity,high selectivity and rapid reaction,and now it has becoming a hot research topic around the world.Today,many great fluorescent probes even come out of the laboratory and have been widely used in biological,chemical,environmental and material fields.The organic small-molecule fluorescent probe which designed on the basis of small organic molecules has the advantages of short synthesis step,low cost and simple operation.However,in practical applications,some probes are easily disturbed by environmental or other factors.Therefore,it is necessary to design and synthesize organic fluorescent probes with high sensitivity,strong anti-interference ability,wide channels and selective specificity.In this paper,based on the common coumarin and trianphonyamine derivative scranked,three new organic small-molecule fluorescent probes have been designed and synthesized which used for respectively detecting hydrogen sulfide（H₂S_n,n>1）,cysteine（Cys）and cysteine（Cys）and cyangen ion（CN^-）with the effect of color-fluorescent dual-channel.The details are as follows:1.Utilizing the nucleophilicity of hydrogen sulfide,using coumarin derivative as fluorophore,2-fluoro-5-nitrobenzoate as recognition group,we designed and synthesised water-soluble,high-sensitivity Reactive fluorescent probe HX-1 for detecting hydrogen sulfide.We have studied its selectivity and sensitivity through UV absorption and fluorescence spectroscopy.The experimental results show that the probe has good selectivity,can specifically recognize hydrogen polysulfide and do not interfered by other biologically active sulfides of similar structure.It also has great sensitivity and the detection limit as low as 0.03μM.What’s more,the probe is highly stabile which can be used in a wide p H range.It can not only be used for the detection of hydrogen polysulfide in pure water,but also successfully realize the detection and fluorescence imaging of exogenous hydrogen polysulfide in Hela cells.This study provides more possibilities for us to design and study many hydrogen polysulfide fluorescent probes with excellent properties in the future.2.Using cysteine to generate a specific addition cyclization reaction with acrylate,a fluorescent probe HX-2 with dual color sensing fluorescence performance was designed and synthesized.Through the detection of the ultraviolet absorption spectrum,fluorescence emission spectrum,sensitivity,selective anti-interference,fluorescence lifetime,and fluorescence quantum yield-related properties of the probes,we examined the performance of probe HX-2.The research found that the fluorescent probe HX-2 has good selectivity to Cys.Not only can quickly identified Cys by observing the color change of the solution,but also conduct quantitative analysis and detection of Cys by ultraviolet and fluorescence spectra.The detection limit is 0.33μM.3.Using triphenylamine as the parent,aldehyde group as the recognitionsite,and make use of the nucleophilicity of CN^-,we designed and synthesized a highly efficient and specific CN^-fluorescent probe HX-3.The detection performance of CN^-was evaluated by comparing the change of ultraviolet and fluorescence spectra of the probe solution before and after adding CN^-.It can be seen from the experimental result that the probe HX-3 exhibits great selectivity and sensitivity to CN^-.Through the change of ultraviolet and fluorescence spectrum before and after the reaction,color-fluorescence dual effect of CN^-detection was achieved.The fluorescence detection limit is as low as 0.09μM,which was much below the World Health Organization’s highest standard for cyanide ion in drinking water（1.9μM）.