Synthesis Of Iridium(Ⅲ) Complexes-based Phosphorescence Probes And Application In Detection Of Hypochlorous Acid And Glutathion

At present,the parent of luminous probes are mainly organic dyes and metal complexes.Compared with traditional organic dyes,iridium complexes have advantages such as large Stokes shift,long phosphorescent emission lifetime,strong light stability,and good biocompatibility,so that they can effectively distinguish excitation and emission wavelengths,prevent the luminescence quenching caused by self-absorption,shield the self-interference of background fluorescence,and effectively avoid background noise.Therefore,it has attracted wide attention in the fields of ion/molecule detection,bioimaging and early diagnosis of diseases,and has become a research hotspot of small molecule active substance tracer and imaging in biological systems.Meanwhile,we can flexibly change the structure of ligands to adjust luminescence characteristics,achieve specific selective recognition and ultra-sensitive detection of different targets.Based on the above,in this study,iridium(Ⅲ)complexes were selected as fluorescent emission groups,and five fluorescent probes of iridium(Ⅲ)complexes were synthesized by introducing different principal and auxiliary ligand and connecting different recognition groups,which were successfully applied to actual sample detection and biological imaging.1.Three iridium(Ⅲ)complexes(Ir-1,Ir-2,and Ir-3)with pentenyl as identification sites had been synthesized.Cl O~-can be detected by multi-signal and test strip experiments using UV-VIS and emission spectra.Due to the difference of ligands CI-(Ir-1),NCS-(Ir-2)and NCO-(Ir-3)excited at 350 nm,the emission wavelength of the three probes is between 519 nm and 524 nm,and the emission lifetime and solid solution quantum yield are different.All the three methods were selective,sensitive and fast for the detection of Cl O~-.After addition of Cl O~-,the fluorescence was obviously quenched in PBS/DMSO solution.The test paper pretreated with probe solution can also detect Cl O~-under the irradiation of portable ultraviolet lamp,and the quenching of green phosphor makes the detection process more simple.2.An Ir-DAMN phosphorescence probe was synthesized by introducing diamino-maleonitrile groups into the N^N auxiliary ligand as the recognition site.Cl O~-can be rapidly and specifically detected in PBS/DMF(v/v=6:4)mixtures.The probe Ir-DAMN itself has almost no phosphorescence.After the addition of Cl O~-,the solution is excited at 430 nm,and the solution fluorescence turns on,presenting bright orange yellow.The solution color changes from orange red to yellow under white light,and the Stoker shift reaches 190 nm,showing a low detection limit.Ir-DAMN probe has also been successfully used in cell imaging to detect endogenous hypochlorous acid,and can accurately locate mitochondria with a localization coefficient of 0.98.Therefore,the probe Ir-DAMN has potential biological applications.3.An Iridium(Ⅲ)complex phosphorescence probe Ir-DNFB was synthesized by introducing 2,4-dinitrofluorobenzene into the N^N auxiliary ligand.When glutathione was added into PBS/DMF(v/v=3:7)mixture solution,the phosphorescence of the probe was turned on within 5 s,and the emission peak appeared at 620 nm under the excitation of 430 nm.The phosphorescence color was orange,and the detection limit was low.In practice,Ir-DNFB probes can locate mitochondria and have good bioimaging of glutathione in living cells.