The Study Of Fluorescence Dyes Based On Coumarin Derivatives: Synthesis And Optical Properties Study

Coumarin derivatives is widely used in fluorescent dyes,probe,medicine and other fields due to its high fluorescent quantum yield,high photostability and good biological compatibility.In order to get more organic fluorescence dyes and probes easily,it's important to look for a more simple method to synthesize different coumarin derivatives fluorescence molecules.In this paper,we designed and synthesized several fluorescent dyes and probes by the coumarin as fluorescenc chromophore,and investigated the spectral properties of the coumarin compounds by the experiment and theory research.This paper study the synthesis and applications of the fluorescent compounds based on coumarin derivatives.The research content mainly has the following three aspects:Part 1: The fluorescence agent of coumarin derivatives were synthesised by an efficient one-pot,three-component reaction in 80-90% yield.These fluorescence agents exhibited high fluorescent intensity and quantum yield.These coumarin derivatives display the different fluorescence in acidity and alkaline condition and the fluorescent colour changed from blue to yellow-green when the pH of solution turned acidic to alkaline.The pH sensitive fluorescence properties of the coumarin derivatives showed larger shift from 441 to 538 nm in wavelength.Experimental results have been confirmed with DFT and TDDFT calculations.Part 2: In this work,we have successfully prepared a novel coumarin fluorescent probe for Fe3+ and the pH change in DMSO.We have investigated the spectra properties of the probe a and especially its activity to metal ions.This probe displays an extreme selectivity and sensitivity to Fe3+ by fluorescence quenching in DMSO,which forms a 2:1 complex with Fe3+ and displays fluorescent quenching.The binding mechanism was studied by binding stoichiometry and DFT calculation,and the quenching mechanism was confirmed by Mulliken's charge distribution which was calculated by quantum chemistry.Part 3: The fluorescence coumarin derivatives were synthesised by an efficient one-pot,three-component reaction in 80-90% yields.We investigated the optical properties of these coumarin derivatives(8a-8d),such as the affection between different solvent about the fluorescence intensity and absorption intensity,and the influence of different substituent group and the concentration of solution.The results show that the fluorescence intensity of the compounds is largest in the DMF.And the absorption spectrum is at approximately 308 nm,the fluorescence spectrum is at approximately 435 nm in the DMF,and the stocks shift is arrived in 127 nm.In our case the fluorescence intensity decreases with the increase of the concentration of the solution called concentration quenching.Additionally,the affection of solvent was also confirmed by TD-DFT calculations.