Synthesis And Properties Of Fluorescent Probes Based On Coumarin And Benzothiazole

Due to its high sensitivity and selectivity,ease of manipulation,good cell membrane permeability,real-time visual imaging,and low cost,fluorescence imaging technology has been shown to be a promising method for monitoring the in vivo microenvironment and efficient approach for small molecules.Viscosity plays a crucial role in the biological microenvironment and varies widely in different regions of the cell.Simultaneous visualization of multiple organelles can help reveal cooperation patterns between different organelles.As a complex parameter,polarity plays a key role in chemistry and biology,and abnormal polarity changes in different subcellular compartments are closely related to disease.Bisulfite(HSO3-)has been widely used as an antibacterial agent,an enzyme inhibitor,and an antioxidant for food,medicine,and beverages after fermentation.We therefore synthesized fluorescent probes for the detection of viscosity,polarity and HSO3-.The specific work content is as follows:1.Two kinds of fluorescent probes CHB and CHN for detecting viscosity were synthesized from 3-aminophenol.The UV-Vis absorption spectra and fluorescence emission spectra of the two probes CHB and CHN in different solvents were explored,showing that the fluorescence intensity and fluorescence quantum yield of the two probes were lower in low viscosity solvents,but higher in high viscosity solvent glycerol.Through the Forster-Hoffmann equation,it was found that there was a good linear relationship between the logarithm value of solution viscosity(lg η)and the logarithm value of fluorescence intensity at 600 nm and 650 nm(lg I600 and lg I650),indicating that probes CHB and CHN can detected changes in viscosity by fluorescence method.The fluorescence of CHB and CHN were hardly affected by pH and had good stability and anti-interference ability.Cell experiments showed that the probes CHB and CHN had the ability to localize various organelles of mitochondria,lysosome,Golgi and endoplasmic reticulum,and it was further proved that the localization of probes was not affected by membrane potential,and probes CHB and CHN can detect viscosity in mitochondria and lysosomes.2.A NIR ratiometric fluorescent probe BTXH was synthesized using ohydroxybenzaldehyde as the starting material.The UV-Vis absorption spectra and fluorescence emission spectra of the probe BTXH in different solvents were explored.The results showed that the emission peaks of probe BTXH in less polar solvents such as Acetone,CH3CN,THF were mainly located between 674 nm and 683 nm,and the emission peaks in large polar solvents such as DMSO,DMF,CH3OH and EtOH were mainly located between 771 nm and 817 nm,indicating its solvent polarity-dependent fluorescence property.The structural changes of the probe in different solvents were further confirmed by the study of the UV-Vis and fluorescence properties of the probe BTXH in different DMF/DCM volume fractions.At the same time,through the study of UV-Vis and fluorescent sensing properties,it was proved that the probe BTXH can be used for ratiometric detection of HSO3-.In the fluorescence emission spectrum,the ratio of fluorescence intensity at 520 nm and 770 nm(I520/I770)had a good linear relationship with the concentration of HSO3-in the range of 2-17 μmol/L.The probe BTXH had a low detection limit(1.1 μmol/L),and good stability,selectivity and antiinterference ability in the detection of HSO3-,and the response speed was fast.The probe BTXH can detect HSO3-in the pH range of 7-9.High-resolution mass spectrometry analysis showed that the recognition mechanism of the probe BTXH was the reaction mechanism of HSO3-induced Michael addition.