Design And Synthesis Of Phosphorescent Iridium(?) Complexes As Probes For Sensing And Imaging Of Copper(?) Ion And Oxygen

Heavy metals readily accumulate to in animals and plants and affect their health.Oxygen is one of the most important exogenous components of aerobic organisms and its content is related to human's healthy.Nowdays,optical probes have gone into the dectection of heavy metals and oxygen.Among optical probes,Iridium complexes have the following advantages:First,they have a long life and can be used for time-resolved imaging to eliminate the fluorescence effect of themself.Second,they have a large Stokes shift,which reduces the overlap between absorption and emission spectra and avoids the decrease of fluorescence efficiency caused by energy transfer.Third,they have good biocompatibility,little toxicity to biological tissue and can be metabolized in vitro.In this work,a phosphorescent iridium complex probe responsive to copper ions and oxygen is designed and synthesized,and its photophysical properties and biological imaging applications are investigated.This paper mainly contains two parts:1.Design and synthesis of a phosphorescent iridium complex probe and its application in the detection and imaging of copper ionsBis(pyridine-2-methyl)-amine(DPA)is a receptor for many cations,including the copper ions.A phosphotic iridium complex Ir1 was designed and synthesized by connecting the DPA unit to the auxiliary ligand of the ring metallized iridium complex via an amide bond.The complex has a phosphorescent emission band at 620 nm,and copper ions can quench the phosphorescent emission.In addition,oxygen can effectively quench the phosphorescence of the triplet excited state of the transition metal complex through energy transfer,so oxygen can also quench the phosphorescence emission of complex Ir1 to some extent.Therefore,the response of the complex to copper ions was studied by fixing the oxygen concentration at 21%O₂(that is,under air conditions),and it was found that the complex probe had specificity and sensitivity,and it was successfully applied to the detection of intracellular copper ions.2.Design and synthesis of dual-phosphorescent iridium complexes probes and their application in the detection and imaging of copper ions and oxygenCopper ions and oxygen can simultaneously quench the phosphorescent emission of the iridium complexes.Therefore,the probe cannot simultaneously detect copper ions and oxygen,and the fluctuation of oxygen concentration during the detection process will reduce the accuracy of the response of the complex to copper ions.Under this premise,Two dual phosphorescent emissive iridium complexes with were designed and synthesized by manipulating the structure of substituents in the ligand of phenylpyridine(ppy)of the iridium complexes.The two complexes can exhibit two emissive bands.The high energy(HE)band is located at about 520 nm and only responds to oxygen,while the low energy(LE)band is located at about 600 nm and only senses towards copper ions.the complexes with the dual-phosphorescence properties exhibited naked-eye distinguishable color changes in aqueous solution existing copper ions or not,under an atmosphere of N₂,O₂ and Air,respectively.In addition,the probes have low cytotoxicity and have been successfully applied to the detection of intracellular copper ions and oxygen.To our knowledge,these are the first iridium complexes used as dual phosphorescenct emission probes for detecting copper ions and oxygen and removing the effect of oxygen on the accuracy of the complex detection.