Synthesis Of Organic Small-molecule Florescent Probes And Near Infrared Fluoresent Dyes

Life system is complex and mysterious.Various active substances（such as bio mercaptan,ROS,RNS,cation and anion,etc.）play an extremely important role in physiological process.At the same time,the concentration of active substances exceeding physiological tolerance may cause irreversible damage to the organism.Therefore,accurate and efficient detection of active species in vivo is very important.In recent years,fluorescence analysis has attracted wide attention due to its advantages of high sensitivity,low detection cost,good selectivity and fast response.As an important branch of fluorescence analysis,organic small molecule fluorescent probes are widely used in environmental and life sciences.On the other hand,organic fluorescent probes are usually based on fluorescent dyes（such as Rhodamine,Coumarin,Cyanine,etc.）,and then modified and derived to have the function of recognizing certain active molecules.Near-infrared fluorescent dyes are favored by more and more researchers because of their advantages such as low background interference,deep tissue penetration and less tissue damage.In this study,we first developed two NIR fluorescent probes,Mito-Red FL-1 and Mito-Red FL-2,with similar structure and properties,for specific recognition of nitrite peroxide（ONOO^-）.Then,we synthesized two NIR fluorescent dyes based on the first two probes.Finally,the near infrared fluorescent dye CH1055 was synthesized.The details are as follows:In the first part,we synthesized two NIR fluorescent probes Mito-Red FL-1 and Mito-Red FL-2 for ONOO^-recognition.The two probes have good selectivity,high sensitivity and low detection limit.In addition,biological experiments demonstrated that both probes could recognize ONOO^-produced by exogenous cells.In addition,both probes have the positioning function of targeting mitochondria,and the special recognition mechanism can avoid the interference of false positive signal.Finally,we applied the two probes to detect the changes of ONOO^-flux in mice and obtained satisfactory results.In the second part,we first designed and derived from Mito-Red FL-1 and Mito-Red FL-2,increased the absorption and emission wavelengths,and synthesized two near-infrared fluorescent dyes（3-c and 3-d）.Then,a NIR dye CH1055 was synthesized,and the relationship between its fluorescence intensity and different solvents was preliminarily studied.Finally,theoretical calculation was carried out to further study its electron distribution,which provided help for the subsequent design.