Synthesis Of D-A Conjugated Compounds With Aggregation-induced Emission Features And Their Applications In Fluorescence Detection

A fluorescent probe is a detector that performs a fluorescent analysis on a specific analyte.It consists of a recognition group,a fluorophore,and a linker.Fluorescent probes have become an indispensable tool in modern science and medicine.Traditional fluorophores are prone to aggregation and lead to the phenomenon of quenching of luminescence（ACQ）,which will reduce the luminous efficiency of the constructed fluorescent probes and directly affect the performance of the fluorescent probes.In 2001,Professor Tang Benzhong’s group reported for the first time the phenomenon of aggregation-induced luminescence（AIE）,that is,fluorescent molecules do not have fluorescent properties in a dilute solution,but show strong fluorescence in an aggregated or solid state.The AIE effect has been widely used in the design and synthesis of fluorescent probes.Such probes can effectively overcome the problem of fluorescence quenching caused by aggregation,and have the advantages of strong photobleaching resistance and low background interference.To date,a large number of AIE molecules with different backbones have been reported.Among them,the synthesis of D-A AIE molecules is simple,and its fluorescence properties can be directly optimized by adjusting the electron-donating group（D）and electron-withdrawing group（A）in the molecule.Based on this,this paper constructs D-A fluorescent probes with different skeletons,and uses the mechanism of aggregation-induced luminescence to realize the fluorescence detection of mercury ions and cucurbituril molecules in water.The specific research content is as follows:1.A dithioacetal ester ratio meter fluorescent probe TSB was designed and synthesized.The probe forms an aggregate state in a mixed solution of CH₃CN-H₂O（v:v=1:99）and emits a strong blue color.1.A dithioacetal ester ratio meter fluorescent probe was designed and synthesized.Fluorescent.After encountering mercury ions,the recognition group dithioacetal ester in TSB is converted into aldehyde group.The intramolecular transfer（ICT）process and the aggregation-induced luminescence（AIE）effect make the solution show strong green fluorescence.Before and after the addition of mercury ion to the TSB aqueous solution,the fluorescence color change can be discerned by the naked eye.2.A dithioacetal fluorescence turn-on probe TSA was designed and synthesized.The probe has good orientation and no fluorescence emission in HEPES buffer solution.When mercury ion is added,the recognition group dithiothioacetal carboxylic acid in TSA is replaced with aldehyde group and aggregation occurs in the solution.TSA has high selectivity for mercury ion detection,short response time,and low detection limit.In addition,the probe TSA can also be detected in printing and dyeing wastewater and soil.Mercury ions.3.A Class of Benzothiazolium-based Fluorescent Probes DABT was designed and synthesized.The probe has aggregation-induced luminescence（AIE）characteristics,and It can achieve different spectral signal responses to CB[6],CB[7]and CB[8]in pure water system.After the addition of CB[6]to the aqueous solution of probe DABT,neither the UV absorption wavelength nor the fluorescence emission wavelength changed,and the fluorescence intensity showed a good linear increase trend;after CB[7]was added,the UV absorption wavelength produced a certain red shift.The fluorescence emission wavelength did not change,but the fluorescence intensity showed a good linear increase trend.After the addition of CB[8],neither the UV absorption wavelength nor the fluorescence emission wavelength changed,and the fluorescence quenched.