Research On Construction Of Heavy Metal Ion Chemical Sensor Based On Benzothiadiazole Derivatives

As we all know,there are various metal ions in nature,which play a very important role in the life of animals and plants living in the natural environment.With the rise of the industrial revolution in the 20th century,the persecution of the natural environment was severely affected by metal ions.Therefore,it is urgent to study a method that can effectively detect metal ions in real time.At present,in the field of detecting and identifying metal ions,fluorescent chemical sensors have come to the fore among many monitoring methods due to their rapid response,easy control,and high sensitivity and have received widespread attention.This thesis mainly continued to synthesize several new fluorescent probes based on the preliminary exploration work.The specific contents are as follows:1.A new type of fluorescence enhancement probe BTD-RDA was designed and synthesized,which contains a conjugated 2,1,3-benzothiadiazole structure as a fluorophore and rhodanine-3-acetic acid moiety as an acceptor,Used for the detection of Hg²⁺.It has a well-bound Hg²⁺detection constant of 1.57×10⁴M^-1.Through 1H NMR titration,HRMS and theoretical calculations,the recognition mechanism of Hg²⁺by BTD-RDA is further proved.In addition,BTD-RDA is used as a fluorescent probe for imaging in cancer cells and zebrafish,indicating that it can potentially be used for Hg²⁺sensing in environmental and biological fields.2.Developed a new type of near-infrared fluorescence enhancement sensor TBBA,which has D-A structure as a near-infrared fluorophore and rhodanine-3-acetic acid structure as an acceptor.The probe has the characteristics of specificity for Hg²⁺selection,fast response speed,and low detection limit.The detection limit is 13.10 n M and the good binding constant is 2.37×10⁴M^-1.Through1H NMR titration,HRMS and theoretical calculations further proved the reaction mechanism of TBBA to Hg²⁺.In addition,TBBA has been successfully used as a fluorescent probe for imaging in living cells and zebrafish,which indicates that the probe can potentially be applied to Hg²⁺sensing in the environmental and biological fields.3.A new type of near-infrared fluorescence quenching sensor TBBH was synthesized.In the THF/H₂O（7:3,v/v,p H=7.4）system,the probe has a long emission wavelength of 633 nm and has a good effect on Cu²⁺.The selectivity and sensitivity,the detection limit is 7.6×10^-8n M,can effectively detect Cu²⁺in the concentration range of 0～1.5eq.In addition,test strips made of filter paper can effectively identify Cu²⁺,and the probe can detect Cu²⁺in actual water samples.