Phosphorescent Iridium Complexes Probe To Detect Intracellular Reactive Species Research

Endogenously bioactive substance widely exist in living cell. Changes of the intracellularenvironment generally is accompanied by the change in spatial and temporal distribution of thebioactive substances, which will lead to various diseases. Therefore, a detailed understanding ofthe generation and distribution of these substances contributes much to the uncovering ofphysiological and pathological functions of them. Obviously, it also has important scientificsignificance. As an efficient and powerful research tool, luminescence probe-based cell imagingfor bioactive substances monitoring has become one of the most important research directionsin the field of chemistry and biology.The luminescence probes mianly consist of organic dyes and metal complexes. Althoughorganic dyes have been researched widely and are porved to be efficient, the photo-andthermostability of them are often unsatisfactory. The luminescence probes derived from metalcomplexes exhibit improved photo-and thermostability and their phosphorescence normallyemits with larger Stokes shift and longer lifetime. Therefore, the atuoflurescence fromendogenous ingredients in living cells can be efficiently avoided through time-resolvedtechnique and therefore, better sensitivity can be obtained. From this point of view, it is worthyto develop metal complex-based phosphorescence sensors for bioactive substances in livingcells.Among the various heavy metal based phosphorescence sensors, iridium complexes shouldbe addressed because of their long emission lifetime, large Stokes shift, high quantum yield,and adjustable emission wavelength resulted from optional ligands. Therefore, based on theexcellent luminescence properties of iridium complex, this dissertation devotes to developingiridium complex-based phosphorescence probes for bioactive substances in living cells and isdivided into three sections:Chpater1. The process in research and application of iridium complexes, the study on thephysiological functions of hydrogen sulfide were reviewed.Chpater2. Two iridium complexes, namely Ir-DPA-Cu and Ir-Cn-Cu with bis(2-pyridylmethyl)-amine (DPA) and1,4,7,10-tetraazacyclododecane (Cyclen) as the ligandswere designed and synthesized for the detection of hydrogen sulfide (H2S). Ir-DPA-Cu was proved to response to cellular thiols, including glutathione (GSH), cysteine (Cys), and H2S, etc.Whereras Ir-Cn-Cu showed high specificity to H2S over other thiols. The quantitative detectionof H2S was achieved by a linear equation of F=736.61+281.76[H2S](μM) with linear rangeof0-15μM and a correlation coefficient of0.9958, respectively. Using confocal fluorescenceimaging, H2S in macrophage (RAW264.7) was analyzed successfully. The results provide anideal phosphorescent probe and corresponding analytical method for the detection of H2S inliving cells and organisms, and exhibit important practical significance.