Synthesis,Properties And Application Of Coumarin Fluorescent Probes

Fluorescent probe with numerous advantages of high selectivity, high sensitivity and low cost were paied attention by people, it is very popular in the field of today’s scientific research. It is also special widely used in such aspects as ion, molecular recognition. Coumarin with the good characteristics of light stability, larger Stoke displacement, high fluorescence quantum yield is treatde as a fluorophore that was known by researcher. Glutathione (GSH; γ-glutamylcysteinylglycine) is ubiquitous in mammalian and many prokaryotic cells and is the most abundant intracellular thiol (1-10 mM; Cysteine:30-200 μM; homocysteine:5-15μM). It is an essential endogenous antioxidant that plays a central role in cellular and defenses against toxins and free radicals. Therefore, the accurate concentration measurement of GSH in physiological media has been considered as an essential factor in these diseases and their therapy because of its biological and clinical significance.This thesis designed and synthesized, coumarin-based fluorescent probe to Glutathione and copper ion. Chlorine lies in 4-position of 7-(diethylamino)coumarin-3-carbaldehyde, where is doubly activated and has been proved to be subject to the thiol-halogen SNAt reaction. The structure were characterized by NMR and TOF-MASS; Using UV-vis absorption spectrograph and fluorescence emission spectrograph we study photophysical property. In 90% aqueous system, addition of GSH to the solution of probe 1 led a red-shifted emissions band from 507 nm to 546 nm, that emerged a ratiometric response. Introduction of GSH to the solution of probe 1 results in a color change from yellow to red-orange and a fluorescence change from green to orange. The detection limit is determined to be 0.38 μM, a Job’s plot exhibits that the reaction between probe 1 and GSH has a 1:1 stoichiometr, the observed rate constant for sensing reaction was determined to be 0.144 ± 0.004 min-1 under pseudo-first-order kinetic conditions. The probe is cell-membrane-permeable and has low cytotoxicity, and the probe is suitable for selective ratiometric fluorescent imaging of GSH in living cells.Di-2-picolylamine (DPA) as a good ligand is always applied in the supramolecular system, the Synthesis of probe 2 was based on chlorinated coumarin and DPA. The structure were characterized by NMR; Using UV-vis absorption spectrograph and fluorescence emission spectrograph we study photophysical property. Probe 2 is high selectivity for copper ion. In CH3CN/HEPES system, the emissions band of probe 2 was at 452 nm. Introduction of copper ion to the solution of probe 2 results in a color change from colorless to yellow and a fluorescence change from blue to quench.