New Schiff Base Fluorescence Probe For Recognition And Detection Of Zinc Ion

Chapter 1:This chapter introduced the generation of fluorescence and the composition of fluorescent molecular probes.The main response mechanism of detecting various metal ions was explained.Importantly,the research status of zinc ion fluorescent probes was reviewed.Chapter 2:Using 8-hydroxyjulolidine-9-carboxaldehyde and 2-（methy-lthio）aniline as raw meterial,a new Schiff base fluorescent probe HP was synthesized and characterized.Addition of Zn²⁺to HP resulted in a dramatic fluorescence enhancement at 480nm in absolute ethanol.The presence of trace water in ethanol significantly quenches the fluorescence emission of the HP-Zn²⁺system.The extent of quenching depends upon the water content and thus,a fluorescence method was developed for the determination of trace water in ethanol.The detection limit is 0.0012%v/v.Chapter 3:A new benzothiazole Schiff base fluorescent probe BTC was synthesized.This probe could detect zinc ion under physiological p H7.4（DMF/H₂O,3/2,v/v）conditions.Due to the ESIPT mechanism of the BTC,the probe has a large Stokes shift（E_x=430nm,E_m=508nm）.After addition of zinc ion,the emission peak at 508nm was gradually weakened and blue shifted to 470nm.This ratio detection could reduce background interference and improve anti-interference ability.The detection limit is 1.51×10^-8M.In addition,the fluorescent color changed from green to blue-green,which could be recognized by the naked eye.And BTC had been successfully applied to cell imaging.Chapter 4:A new fluorescent probe BTT was designed and synthesized.The probe could detect zinc ions under physiological p H 7.4（methanol/water,3/2,v/v）conditions.The binding ratio of BTT and Zn²⁺was 1:1.The presence of Zn²⁺caused a huge blue shift of the emission wavelength of BTT from 570nm to 488nm with a"naked eye"color from orange to green.The possible mechanism of this emission change was the inhibition of excited state intramolecular proton transfer（ESIPT）and the formation of chelation enhanced fluorescence（CHEF）when the complex formed.The detection limit of Zn²⁺is 37.7n M.In addition,the probe BTT showed good imaging ability for exogenous Zn²⁺in Hela cells and endogenous Zn²⁺in SH-SY5Y neuroblastoma cells.Chapter 5:This chapter summarize the work of this paper,and compare the performance parameters of the three probes in this work.In addition,the future research work is prospected.