Study On Synthesis And Properties Of Curcuminoids ? Dicyanomethylenepyran Fluorescent Probes

Fluorescent probe technology is widely used in biology and medicine because of its high sensitivity and selectivity,which has been used to analyse and detect active substances,metal ions and small molecules quantitatively and qualitatively in living organisms.In this thesis,two fluorescent probe molecules that can specifically recognize cysteine and one fluorescent probe molecule that can detect hydrazine and Fe³⁺are designed and synthesized.Their optical properties and response mechanisms are studied and discussed.The details are as follows:Chapter 1:In the first chapter,the introduction describes the concept and structure of fluorescent probes,the recognition mechanisms of fluorescent probes,the concept and research progress of curcumin,the research progress of biological thiol fluorescent probes,and the research progress of hydrazine fluorescent probes.Chapter 2:In the second chapter,two fluorescent probes CAC-1 and CAC-2were designed and synthesized which specifically recognize cysteine.I selected the curcumin as fluorophore and acryloyl ester group as recognition group.The probes had the advantages of simple synthetic route,high yield and fast response rate.After reacting with cysteine,the fluorescence of the probe CAC-1 system changed from yellow-green to light pink,and the fluorescence intensity was significantly weakened with a red shift of 16 nm;the fluorescence of the probe CAC-2 system changed from green to yellow,and the fluorescence color changed from green to yellow with a Stokes shift of 28 nm.The detection limits of the two probes for cysteine were 14.19?M and 27.02 m M,respectively.Moreover,both probes had good p H adaptability,selectivity,and anti-interference,and could be identified by naked eyes.Chapter 3:In the third chapter,hydrazine fluorescent probe DCMB based on ICT mechanism were designed and synthesized,using dicyanomethylenepyran derivatives as fluorophore and cyanovinyl as recognition group.The cyanovinyl group reacted with hydrazine and converted to the corresponding hydrazone DCMBN.The electron-withdrawing ability of this group lead to the increase of the electron cloud density,and the ICT effect inside the probe was weak.After the transformation,the ICT effect became stronger and the fluorescence intensity increased significantly,and the fluorescence color changed from green to blue.At the same time,the color of probe solution changed from yellow to colorless,which can be used for naked eye identification of hydrazine.The probe exhibited good selectivity and anti-interference,with a detection limit of 26.1?M for hydrazine.Chapter 4:In the fourth chapter,the recognition of Fe³⁺by probe DCMB was studied,and its optical properties,response time,concentration titration and metal coordination mechanism were studied.Fe³⁺can coordinate with the cyano group of the probe molecule resulting in complete quenching of fluorescence,and the coordination ratio of ligand to Fe³⁺was 1:1.The detection rate of Fe³⁺by the probe DCMB was fast and can be completed in an instant.The fluorescence intensity of the probe system had a good linear relationship with the concentration of Fe³⁺,and the detection limit of Fe³⁺was 13.6?M.