Synthesis And Application Of Fluorinated Tetrapod Azine-based Fluorescent Sensor Molecules

Fluorescence sensors attracted wild attentions due to their excellent properties of such as high selectivity,short response time,and simple operation process,fluorescence sensors also have been widely used in many fileds.How to improve the detection sensitivity and selectivity of fluorescent sensors has always been challenging topic in this field.In order to improve the selectivity and sensitivity of the sensor molecules,researchers have improved the design of the sensor from different approaches.It has been found that the introduction of fluorinated functional groups can change the charge distribution of sensor molecules and have an impact on the recognition performance of sensor molecules,which is expected to improve the selectivity and detection sensitivity of sensor molecules for specific guests.In addition,in order to improve the selectivity and sensitivity of sensor recognition,“synergistic effects”between multiple functional groups often been employed to improve the binding and recognition properies of chemosensor.Herein,in order to improve the selectivity and sensitivity of the sensor to specific guest molecules,based on the investigation of fluorinated functional compounds and multipod fluorescent sensor molecules,fluorinated functional groups as well as“synergistic effects”were rationally introduced into the design of chemosensors.To achieve“synergistic effects”,the sensor molecules designed in this paper adopt tetrapod structure.There are three parts reaserch contents as following:Part one:The contrast experiments indicated that the introduction of fluorine atoms in TF1 could increase the sensitivity of TF1 fluorescence detection of Cu²⁺.The mechanism of TF1 sensitive detection of Cu²⁺was studied through a series of experiments.Based-on these,a fluorescent test strip capable of detecting Cu²⁺was prepared,which can clearly detect Cu²⁺in solutions with low Cu²⁺concentrations.Part two:Due to the TF1 containing this paper also studied the recognition performance of TF1 on picric acid.After adding a series of organic acids to the TF1solution,only picric acid can completely quench the fluorescence of TF1 and cause a color change in the TF1 solution.Therefore,TF1 can selectively and sensitively recognize picric acid under fluorescence and visible light,with a short response time.Meanwhile,because TF1 solid has a strong tangerine fluorescence,a fluorescent material also has been prepared by upload TF1 to silica gel.This fluorescent material can selectively detect vapor of volatile organic compound ethylenediamine.Part three:Two compounds,TF1 and TF5,with similar structures to TF1 with different numbers of fluorine substituents,were designed and synthesized and their fluorescent properties also have investigated.As a result,the fluorescence intensity of such molecules weakening with the number of fluorine atom substitutions increases.Afterwards,the recognition properties of TF0,TF1,TF2 and TF5 on the pollutant perfluorooctanoic acid（PFOA）have been studied.After adding PFOA to TF0,TF1,TF2 and TF5 solutions,respectively,TF0,TF1,TF2 shows almost no change in fluorescence intensity.While,addition of PFOA could induce the TF5 solution fluorescence enhancement.These results indicate that TF5 can selectively detect PFOA.Finally,the interactions between these four compounds and F^-have been studied.After adding F^-to TF0,TF1 and TF2 solutions,the fluorescence of the solution showed red shifts and quenches finally.Adding F^-to TF5 solution resulted in a blue shift and enhancement of fluorescence.This research result indicates that TF5 can be used as a fluorescence sensor to detect F^-.In summary,this paper has designed and synthesized a series of tetrapod azine sensor molecules with different numbers of fluorine atom substitutions.The molecule TF1 substituted with p-fluorophenyl can selectively recognize Cu²⁺,picric acid,and ethylenediamine vapor.Among them,the introduction of fluorine atoms improves the sensitivity of TF1 in detecting Cu²⁺and picric acid.Pentafluorophenyl substituted TF5can fluorescence detect PFOA and F^-.These research results have certain application prospects.