Design, Synthesis And Application Of PH Probes Based On Iridium (Ⅲ) Complexes

pH is an important parameter of aqueous solution system which effect of chemistry, biochemistry and environmental science, in recent years, a number of fluorescent probes have been reported. Compared to organic fluorescent probe, phosphorescent transition-metal probe has excellent color tunability, large Stokes shift, long emission lifetime and high quantum efficiency. Therefore, it is of great significance and application prospect to research and develop this kind of iridium(Ⅲ) complexes probes in the pH sensing field.In this paper, it is firstly designed and synthesized a main ligand containing piperidine groups metal phosphorescent iridium(Ⅲ) complexes Ir1, which is used for detection of p H. Analyzed the photophysical properties of the complexes, it is found that the absorption and emission properties of complexes in different solvent have no great changes. Indicating that the property of phosphorescent probe is not affected by the solvent polarity. Then, the emission spectra of the complexes in buffer solutions of different pH were studied and the changes of Ir1 emission lifetime were studied by means of confocal imaging and time resolution techniques. It is found that the lifetime of the complex was gradually increased with the add of the acidity, thus, the detection of pH in physiological cel s was realized.On the basis of the previous chapter. In this paper, it is synthesized the phosphorescent iridium(Ⅲ) complexes Ir2, Ir3 and Ir4, that Pyridyl benzimidazole containing 18 carbon chain as C^N ligand, Ir3 for morpholine as N^N ligand, Ir4 for piperidine as N^N ligand and Ir2 for not containing functional gro ups of the model complexes. Complexes Ir3 and the Ir4 can block on the surface of the cell membrane, and then the pH of the cell membrane was detected. Analyzed the photophysical properties of the complexes, it is found that with the acid drops emission peak of the complexes gradually shifts from 550 nm to 600 nm, and the intensity gradually increased. Confocal imaging the complexes Ir2、Ir3 and commercial cell membrane dye DiO, overlap were respectively 90.2% and 91.5%, it is illustrate that the phosphorescence probe for specific imaging of cell membrane.