Design And Research Of Phosphorescent Sensor Based On C=C Unsaturated Double Bond For Reactive Oxygen/Nitrogen Species

Reactive oxygen and nitrogen species(ROS/RNS)with high chemical reactivity are neutral and anionic small molecules produced in various types of cells and are closely related to multiple life activities in organisms.Many ROS/RNS play a vital role in various pathological processes,such as Alzheimer's disease,cancer,diabetes,cardiovascular and cerebrovascular disease,etc.The life span of these active substances is usually very short,and conventional detection methods are difficult to work.Photoluminescence probes with high sensitivity and selectivity can be used for real-time imaging in vivo to detect various active substances and study their role in physiological processes.Among them,the fluorophore based on C=C unsaturated double bond with high reactive sites can not only undergo a nucleophilic addition reaction with active sulfur species with strong nucleophilic ability but also be oxidized by highly active ROS/RNS.This process can cause the change of the electron distribution and interrupt the?-?conjugation in the probe,thereby exhibiting an excellent colorimetric or ratiometric fluorescence response to the active material.At the same time,the metal complexes as flexible photoluminescence molecules usually have the advantages of larger Stokes shift and longer luminescence lifetime,which can reduce the interference of background signals,and are widely used in the design and research of ROS/RNS sensors.Therefore,we designed a series of Ru(II)/Ir(III)phosphorescent sensors based on C=C unsaturated double bonds to detect biologically active substances by combining the advantages of the unsaturated double bond fluorophore and metal complexes.Among them,metal phosphorescent probes containing malononitrile groups can be used to detect ONOO^-in vitro,target mitochondria,visualize ONOO^-in cells,and detect drug-induced liver injury.In addition,the Ir(III)phosphorescent complex containing the pyridine salt group can also sensitize O₂ in the air and generate singlet oxygen under ultraviolet light,which has excellent potential for application in photodynamic therapy.