| Fluoride ions always affected people’s health problems,and researchers in related fields were committed to the detection of fluoride ions.On the other hand,organic solvents had always been indispensable solvents in chemical-related fields,and the toxicity and non-degradability of organic solvents also endangered the enviro nment and human health.At the same time,water was an impurity of many organic reactions.Production might bring immeasurable hazards,so the detection of organic solvents and the detection of water content in organic solvents were also extremely important.In this thesis,salicylaldehyde derivatives were synthesized as colorimetric fluorescent probes to explore their selective recognition of anions,detection of organic solvents and moisture content in organic solvents,and their encryption and anti-counterfeiting applications.The main work was summarized as follows:1.In the first chapter,we briefly introduced the research significance of fluorescent sensors for detecting anions,organic solvents and water content in organic solvents,the research status of fluoride ion chemical sensors,the application of polarity-sensitive chemical sensors and the research status of salicylaldehyde chemical sensors.On this basis,the idea of this thesis was put forward.2.Two simple sensors,BDQ and BQ,were synthesized using salicylaldehyde as a functional group,which chemical structures were determined by the 1H,13C NMR and mass spectra,and their selective recognition of anions was investigated by UV-spectrophotometry and fluorescence spectroscopy.Once the F-ions were added,the color of the sensor solutions obviously transformed from colorless to yellow,directly recognizing by naked eyes.On the other hand,these sensors were almost non-emissive in solutions,the green fluorescence were successfully turned on after adding fluoride anions,but other anions caused no any changes.The results showed that BDQ and BQ had colorimetric and green fluorescence recognition properties for F-ions.The detection limit was as low as 7.5×10-7 M,and the chemical interaction ratio of sensor to fluoride ion was 1:1.Through NMR,mass titration experiments and theoretical calculations,it was deduced that the interaction mechanism between the sensor and F-ions was the excited state proton transfer process.Finally,the sensor was also applied to F-ion detection in real enviro nment and to develop anti-counterfeiting patterns.3.Two sensors with D-π-A structure,TPA-SYQ and TPA-BQ,were synthesized,their chemical structures were finely demonstrated by the NMR,mass and single crystal results and photophysical properties were investigated by UV-spectrophotometry and fluorescence spectroscopy.The results showed that the fluorescence emission of both sensors is highly sensitive to solvent polarity.The emission spectra were gradually red-shifted with increasing solvent polarity and also showed fluorescence emission from bright blue to weak yellow,their fluorescence behavior in binary solvent system was similar to that of single solvent.Theoretical calculations confirm that the two sensors have intramolecular charge transfer,and the different stability of the dipole-dipole interaction of excited state molecules in different polar solvents leads to different fluorescence emission of the sensors in different polar solvents.The two sensors are also used to detect volatile organic compounds（VOCs）,moisture content in organic solvents,and to design encryption and anti-counterfeiting patterns.In addition,TPA-SYQ exhibited a fluorescence response from weak orange to bright green emission to F-ions,relevant detection limit as low as 5.1×10-7M,and chemical action ratio of 1:2.The sensing mechanism was proved to be deprotonation by NMR and theoretical calculations. |
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