Synthesis And Properties Study Of Novel Fluorescent Probes Based On Small Organic Molecules

The synthesis and application of fluorescent probes as a cutting-edge discipline in various disciplines are gaining much attention from researchers.Its working principle is to show the changes of the molecules in the form of optical signals.The typical characteristics of fluorescent probes are high selectivity,sensitivity,short detection time,low cytotoxicity good stability and easy operation.The combination of fluorescent probes and biological imaging can be used to trace a substance in a living body,to achieve real-time detection of substances in situ,and even to monitor the physiological process.Therefore,the study of fluorescent probe is of great significance.In this paper,we synthesized three kinds of fluorescent probes including a fluorescent probe as a Schiff base derivative for the detection of zinc ion;a cyanine-based probe for the detection of hydrazine;a BODIPY-based fluorescent probe for the detection of DCP.In the first part,we designed a fluorescent probe for the detection of zinc ion based on Schiff base.The probe was synthesized by the reaction of Schiff-Zn-1 and Schiff-Zn-2 at room temperature.Zinc ion has a strong coordination ability,and it can form a relatively stable complex with the probe.Compared with the probe,the degree of conjugation of the probe-Zn becomes larger and the rigid plane of the complex is more stable,which leads to the remarkable redshift.The response time of this probe is 17 s and the detection limitation is 1.3×10^-8 mol/L.The probe was successfully applied to the detection of zinc ion in living HeLa cells.In the second part,a ratiometric fluorescent probe for the detection of hydrazine was synthesized by using ketocyanine as fluorophore and 4-bromobutyric acid as recognition group.The strong nucleophilic hydrazine substitutes bromine from 4-bromobutylate,and then the free amino group in the intermediate can cut down the ester group which releases the hydroxyl group in the probe showing the strong fluorescence emission.The response time was 18 min and the detection limitation is 1.19×10^-8 mol/L.The probe was successfully used for the detection of hydrazine in cells and in mice.In the third part,we synthesized a fluorescent probe for the detection of DCP containing BODIPY core as fluorophore and hydroxyl group as recognition group.DCP is very toxic and strongly electrophilic.The probe can detect DCP by the electrophilic substitution reaction with the hydroxyl group.The reaction hinders the rotation of the group containing the hydroxyl group due to steric hindrance and further blocks the PET process from the electron-donating group to electron-withdrawing group.Thus,the probe demonstrates the strong enhancement of fluorescent emission intensity by the reaction of DCP.The response time of the probe was 9 min and the detection limitation was 1.3×10^-8 mol/L.Test paper containing the probe was successfully designed for the fast detection of DCP in the environment.