Synthesis Of The Phosphorescent Probes Based On Iridium （Ⅲ） Complexes And The Detection For Cu²⁺

Chemical sensors,also known as chemical probes,are particularly important because of their great significance in many fields,such as chemistry,biology,medicine and environmental research.A chemical sensor can be defined as a compound that detects the analytes by adjusting the change of one or more attributes in the system,such as changing absorption,emission or redox potential.Because of its high sensitivity,easy visualization and short response time,fluorescence detection is considered as one of the most effective sensor applications.Chemical sensors can be divided into fluorescent chemosensors and phosphorescent chemosensors.Owe to modifying the chemical structure easily and high quantum yield,they has been widely concerned and researched.Compared with fluorescent chemical sensors,phosphorescent chemosensors have excellent photophysical properties,such as high luminescence efficiency,easy adjustment of luminous color,long emission life,etc.Because of their long phosphorescence emission lifetime,the influence of short lifetime background noise can be avoided such as fluorescence and scattered light.And the chemical stability and biocompatibility are good.These outstanding properties make it have a good application prospect in sensing and biological imaging.Excessive or too little heavy metal ions will have a great impact on organisms and even cause disease.Cu²⁺ plays a particularly important role in many physiological processes in organisms and is also an important environmental pollutant.The strong ligand binding of Cu²⁺ is an important basis for exploring biological and medical functions,however,aberrant levels of Cu²⁺ can result in neurodegenerative diseases such as Alzheimer’s disease,prion disease,Menkes’ disease,Parkinson’s disease and Wilson’s disease.Therefore,the understanding of the effects of Cu²⁺ in biological and environmental field requires a reliable,universal quantitative method.In this thesis,three phosphorescent chemosensors which can quantitatively detect Cu²⁺ are introduced.The addition of 2,2’-dipicolylamine as cationic receptor in the auxiliary ligand enhances the recognition ability of Cu²⁺.By changing the ring metal dichlorobridged compounds,the luminescent color of iridium complex was adjusted,and three kinds of iridium complex phosphorescent chemosensors,red,bright yellow and green,were obtained.First,we characterized three phosphorescent iridium complex probes by nuclear magnetic resonance（NMR）and high resolution mass spectrometry（HRMS）,and then studied their chemical and photophysical properties.It was found that all of them could recognize Cu²⁺ with high sensitivity,which showed obvious phosphorescence quenching,and had good detection limit and reversibility.The three iridium complex phosphorescent probes have good thermal stability,and the recognition of Cu²⁺ is not affected at pH < 10.We choose to research cytotoxicity and imaging in living cells in cervical cancer cell Hela.The results of MTT showed that the phosphorescent probe of yellow green iridium complex with coumarin structure had little toxicity to cells,and the imaging results showed that they all have good membrane permeability and good imaging characteristics in detecting Cu²⁺ in living cells.