Synthesis And Properties Of Coumarin-based Fluorescent Probes For Cu(?),Ni(?) Heavy Metal Ions

Heavy metal pollution has the characteristics of wide source,easy accumulation and difficult degradation.It poses a serious threat to the environment and biology.Fluorescent probes have become powerful tools for detecting heavy metal ions in the environment and organisms.Coumarin derivatives are widely used in fluorescent and colorimetric probes due to their excellent optical properties.A series of highly selective and sensitive Cu²⁺and Ni²⁺fluorescent and colorimetric probes have been designed and synthesized based on 7-diethylaminocoumarin.The structure,optical properties and recognition mechanism of these probes have been systematically studied.This paper is composed of six chapters:Chapter 1:A brief introduction was given of fluorescent probes,the application of coumarin in fluorescent probes,the harm of heavy metal ions,the current status of coumarin-based Cu²⁺and Ni²⁺fluorescent probes.Chapter 2:7-diethylaminocoumarin-3-carbaldehyde-?3'-hydroxy-2'-naphthoyl?hydrazone?L¹?was designed and synthesized.L¹ is a fluorescent and colorimetric probe for Cu²⁺,it exhibits long excitation wavelength and high sensitivity,with a detection limit as low as 5.78×10^-77 M.Chapter 3:7-diethylaminocoumarin-3-carbaldehyde-?fluorescein?hydrazone?L²?was de-signed and synthesized.L² is a fluorescent and colorimetric probe for Ni²⁺,it is a rare Ni²⁺multichannel chemical sensor with high selectivity and sensitivity.Chapter 4:3-methoxy-2-hydroxy-benzaldehyde-?7'-diethylaminolcoumarin-3'-formyl?hyd-razone?L³?was designed and synthesized.L³ is a fluorescent probe for Cu²⁺,it has the advantages of low cost,good selectivity and high sensitivity,the detection limit is 5.61×10^-7 M.Chapter 5:6-hydroxychromone-3-formaldehyde-?7'-diethylaminocoumarin-3'-formyl?hydr-azone?L⁴?was designed and synthesized.L⁴ is a fluorescent and colorimetric probe for Cu²⁺,it shows good selectivity and obvious color change.By comparing the properties of L¹,L³ and L⁴,some design ideas of Cu²⁺quenched fluorescent probes and colorimetric probes are summarized.Chapter 6:Summary and prospect.