Synthesis Of Coumarin-based Schiff Base Compounds And Identification Of Copper(Ⅱ)

As a transition metal,copper is the third most abundant essential trace element in the human body,and its content is usually very low in cells and tissues.Excessive accumulation of copper will damage cell homeostasis.The detection and identification of copper in environmental and biological samples are important for monitoring the health status of living systems.Fluorescent probes can provide corresponding fluorescence responses to most chemical and biological analytes,among which coumarin has the advantages of high fluorescence and easy modification,and is often used in the design and analysis of fluorescent probes.In this thesis,using 7-hydroxycoumarin as the basic framework,two kinds of coumarin fluorescent probes were designed and synthesized by Schiff base condensation linking different groups with aldehyde groups on 8-site,and their recognition performance was studied.The specific content of the thesis is as follows:In the first part,a fluorescent probe（CNDH）containing benzophenone hydrazone was designed and synthesized.CNDH probe has the characteristics of aggregation induced emission（AIE）,and recognizes Cu²⁺by fluorescence quenching.The probe CNDH recognizes Cu²⁺by fluorescence quenching.The structure and properties of the probe CNDH were determined by means of hydrogen nuclear magnetic resonance spectroscopy,high resolution mass spectrometry and atomic force microscopy.The recognition performance of CNDH probe for Cu²⁺was studied by fluorescence spectrum.Job’s plot curve was used to determine that the coordination ratio of probe CNDH to Cu²⁺was 2:1,and the high sensitivity and specificity of probe CNDH for Cu²⁺recognition could be achieved,which showed obvious fluorescence quenching.In addition,the detection limit of CNDH probe for Cu²⁺can reach 2.51×10^-6mol/L.In the second part,fluorescent probe（CNDP）based on 2,4-Dimethylphenylhy-drazine hydrochloride Coumarin was designed and synthesized.After the structure of probe CNDP was determined,the recognition effect of probe CNDP on metal ions was studied through the change of fluorescence spectrum.The structure of probe CNDP was determined,the recognition effect of probe CNDP on metal ions was studied through the change of fluorescence spectrum,and the detection limit was determined to be 1.66×10^-7 mol/L,which could realize the effective,sensitive and specific recognition of Cu²⁺,showing obvious fluorescence enhancement.In conclusion,both probe CNDH and probe CNDP can specifically identify Cu²⁺.The detection limit of fluorescently enhanced fluorescent probe is higher than that of fluorescently quenched fluorescent probe,and probe CNDP has higher sensitivity to Cu²⁺.