Synthesis And Properties Of Silicon And Phosphorus Substituted Near-infrared Rhodamines

In recent years,fluorescence imaging with near-infrared molecular fluorophores and probes has received widespread attention.It has been accepted that the introduction of bridging heteroatoms into rhodamine scaffold could regulate the optical properties of resulted fluorophores.The wavelength of maximum absorption and emission for silicon-based rhodamine and phosphorous-based rhodamine are bathochromically shifted into near-infrared region(NIR),satisfying the requirement of near-infrared fluorescence imaging.In this thesis,we are devoted to propose novel synthetic routes for the silicon-based and phosphorous-based rhodamine dyes.Moreover,we have constructed phosphorous-based rhodamine fluorescent probes PR-HOCl and PR-ONOO~-.We have also confirmed that probe PR-HOCl can sensitivity monitor HOCl in vivo and probe PR-ONOO~-can accurately locate lysosomes in situ.(1)Synthesis of silicon-based and phosphorous-based rhodamine fluorescent dyesTraditional methods are typically used for the synthesis of silicon-based rhodamine derivatives.The synthetic methods are usually difficult and time consuming,resulted in great difficulties for application.Herein,we designed and optimized the synthetic routes of silicon-based and phosphorous-based rhodamine derivatives.We optimized the synthetic conditions of the key intermediates of silicon-based rhodamine,and eventually raised the yield.In addition,the change of fluorescence intensity of benzylbenzene-containing phosphoryl rhodamine in different pH environments was also investigated.(2)Construction and deep imaging of hypochlorous acid fluorescent probe based on near-infrared phosphorus-substituted rhodamineHypochlorous acid(HOCl)plays an important role in many cellular regulation processes,however,limited fluorescent probes can achieve deep imaging of HOCl in vivo.In the work,a phosphorus-based rhodamine near-infrared fluorescent probe PR-HOCl was designed and synthesized to sensitively monitor HOCl.Based on excellent photostability,biocompatibility and tissue penetrability,the designed probe PR-HOCl turns out to be very suitable for in depth imaging.(3)Fluorescent probe based on near-infrared phosphorous-based rhodamine for precise positioning of lysosomesPeroxynitrite(ONOO~-)has received widespread attention as a key biomolecule in various physiological and pathological processes.However,there are few fluorescent probes that can selectively detect ONOO~-in the lysosomes in NIR.Herein,a phosphorus-substituted rhodamine probe,PR-ONOO~-,was synthesized and used to sensitively monitor ONOO~-and accurately locate lysosomes.In this thesis,we mainly focus on the development of novel synthetic methods of silicon-based and phosphorus-based rhodamine dyes and the construction of probes based on phosphorous-rhodamine.We have studied the spectroscopic properties of silicon-based and phosphorus-based rhodamine fluorophores.Probe PR-HOCl was used to monitor HOCl with high sensitivity and probe PR-ONOO~-was designed to accurately locate lysosomes and detect peroxynitrite ions in vivo.