Synthesis And Properties Of Two New Near-Infrared Fluorescent Probes For ONOO~-

Peroxynitrite(ONOO-)plays very important roles in the living systems.However,due to its very short half-life in living systems,it is very difficult to measure ONOO-by conventional detection method.In contrast,fluorescence detection has attracted widespread attention because of its low detection cost,simple operation,high sensitivity,and real-time detection ability.Compared with the fluorescent probes in the visible region,NIR fluorescence probes have the advantages of low background interference,deep tissue penetration and minimumn tissue damage to biological samples,which is very beneficial for the detection of endogenous and exogenous ONOO-.In this work,we synthesized two new near-infrared fluorescent probes for detection of ONOO-.1.We first synthesized a near-infrared fluorescence probe(probe 1)based on rhodamine framework.The probe uses a acylhydrazide as the reactive site and recognizes ONOO-through oxidative hydrolysis.Our results showed that this probe shows excellent sensing properties for ONOO-including:rapid response(<2 s),high selectivity and sensitivity,long excitation and emission wavelength,significant fluorescent enhancement(>100-fold).Moreover,the color of the solution changed significantly before and after the reaction,which also enables a convenient visual detection.In addition,this probe has low cytotoxicity and can be applied for real-time detection of both endogenous and exogenous ONOO-in living cells.2.Based on the above results,we further synthesized probe 2,a new rhodamine-coumarin dyad-based ratiometric and near-infrared fluorescent probe for ONOO-.Our results showed that this probe can quickly respond to ONOO-with high sensitivity and high selectivity in a nearly pure aqueous phase test system,accompanied by the obvious color changes and distinct ratiometric fluorescence signal changes from the visible region to the near-infrared region.Moreover,we have also successfully applied this probe for detection of endogenous and exogenous ONOO-in living cells,indicating that the probe has good application potential in living systems.