Design,Synthesis And Recognition Performance Of Coumarin-based Fluorescent Probes Containing Sulfur Atoms

With the development of industry and agriculture,more and more environmental problems appeared.Among them,the problem of heavy metal pollution is particularly prominent,which has a great harm to the environment and human health.Therefore,it is of great significance for human development to find a highly efficient and sensitive way to identify heavy metal ions in the environment and organisms.Because of its advantages of simple operation,high sensitivity and high practicability,fluorescence analysis is often used in the field of metal ions detection.In this paper,based on the design principle and development trend of coumarin fluorescent probe molecules,several kinds of probe molecules have been designed and synthesized,four of which can respond to metal ions rapidly,and their properties have been studied.The coumarin probe molecules A1-A4 were designed and synthesized,in which A1 and A2 contained bimolecular mercaptoethanol and monomolecular mercaptoethanol respectively,In CH₃CN/HEPES?9:1,v/v?mixed system,the probe molecule A1 achieved a specific response to Hg²⁺,the fluorescence value increased by 3.53 times,the response ratio was 1:1,the complex constant was 8.71×10³ M^-1,the detection limit was 3.2×10^-6 M,and it had good stability and reversibility.But the selectivity of probe molecule A2 was poor.Probes A3 and A4 contained diethyl mercaptan and ethyl mercaptoacetate respectively.In CH₃OH/H₂O?9:1,v/v?mixed system,probe molecule A3 showed a better specific and selective response to Hg²⁺,the fluorescence value increased by 3.05 times,the response ratio was 1:1,the complex constant was 4.44×10⁴ M^-1,the detection limit was 9.87×10^-7 M,and the stability was good.The probe molecule A4 can recognize Fe³⁺in the mixture of CH₃CN/H₂O?9:1,v/v?.The fluorescence value increased 6.26 times,the response ratio with Fe³⁺is 1:1,the complex constant is 3.30×10⁵ M^-1,and the detection limit is 7.93×10^-7 M,which has certain reversibility and stability.The coumarin probe molecules B1-B2 were designed and synthesized,which contained bimolecular hexahydropyridine dithiocarbamate derivatives and morpholine dithiocarbamate derivatives respectively.The probe molecule B1 can identify Fe³⁺better in CH₃CN/H₂O?1:1,v/v?mixed system,and has good stability and anti-interference ability.The response ratio is1:1,and the complex constant is 7.03×10⁴ M^-1.The detection limit was 4.38×10^-7 M.