Manufacture Of Phosphorescence Iridium Complexes Based On Microenvironmental Response And Application In Disease Diagnosis And Treatment

With long phosphorescence lifetimes,large Stoke shifts and tunable emission,iridium(Ⅲ)complexes have been extensively used as probes for organelle imaging.In this article,iridium(Ⅲ)complexes were used as phosphorescence moieties,and used the change of the main ligand structure in various solution situation to adjust the photophysical and photochemical property.The change of solution property could be transferred to the change of optical signal,also enable to observe the organelle activities in the living cells by phosphorescence imaging.In the first part,organelles,the synthesis and properties of phosphorescent iridium(Ⅲ)complexes,fluorescence imaging technique,the function,structure and properties of lysosome and mitochondria were outlined.The background of photodynamic therapy(PDT),the huge research prospect of iridium(Ⅲ)complexes used as PDT agents were introduced.The general design thought of lysosome-targeted and mitochondria-targeted metal complexes,the application of the lysosome-targeted and mitochondria-targeted iridium(Ⅲ)complexes in the living cells were highlighted.Finally,according to the research status of iridium(Ⅲ)complexes,the research ideas of this paper are proposed.In the second part,we designed three dinuclear iridium(Ⅲ)complexes with different length carbon chain as the main ligand,which have double terminal pyridine group.A uninuclear iridium(Ⅲ)complex was set as control.Due to the difference of the length of the carbon chain between the two iridium nuclei,these iridium(Ⅲ)complexes show different phosphorescence lifetime and phosphorescence intensity in solution with different viscosity.The change of phosphorescence lifetime and intensity is positively correlated with the change of solution viscosity.In the glycerol-water system liquid,the logarithm of the phosphorescence lifetime and intensity of 1 was linear with the logarithm of the solution viscosity.3 also has the viscosity response ability,but the response accuracy was much less than 1.However,compound 2,which is connected with two pyridine groups by rigid C-C s bond,can be hardly seen the change of phosphorescence intensity under the ultraviolet lamp.By applying 1 to cell imaging,it was found that compound 1 could be located in lysosomes,and 1 could be used to distinguish tumor cells from normal cells by using the difference in phosphorescent lifetime and intensity,as the difference of lysosomal microviscosity of tumor cells and normal cells.In the third part,two pairs of isomeric iridium(Ⅲ)complexes(Ir1-Ir4)were designed,which are derived from the exchange of active hydrogen on the main ligand imidazole ring and inevitably produce isomers.All four iridium(Ⅲ)complexes showed different p H responses to the solution,but Ir1 and Ir2 had better p H sensing capabilities.In an acidic buffer,the phosphorescence of the complexes is inhibited and can be recovered in alkalinity.Through co-localization experiments and ICP-MS,it was confirmed that the complexes were located in mitochondria in the cells.As the lower p Ka(ca.7.4)and better sensing ability,Ir1 and Ir2 can be used as p H probes targeting mitochondria,while Ir3 and Ir4 have potential as photodynamic therapy agents due to their greater phototoxicity.