Synthesis And Research Of Cyclometalated Iridium Complex-based Fluorescent Probe With Phenylpyridine Ligand For Detection Of Phenylthiophenol

Thiophenol,as a class of important chemical reagent and intermediate produce had been widely used in the synthesis of medicine,materials,dye and various chemicals.At the same time,thiophenol is also a highly toxic and carcinogenic pollutant,even if the trace exposure,may cause great harm to the human body and the environment,such as central nervous system damage,respiratory diseases,hind limb paralysis and even death.Therefore,the development of a simple,rapid,sensitive and specific method for the detection of thiophenol is of great significance.Among them,the fluorescence probe method was considered to be one of the most effective methods because of its high sensitivity,good selectivity,convenient operation,and the advantages of real-time monitoring of analyte in biological monitoring,environmental analysis and medical diagnosis.In addition the recognition of aromatic thiolss is susceptible to interference with aliphatic thiols due to their similarity in structure and nucleophilicity.However,many studies have shown that thiophenol(p Ka = 6.5)exhibited lower p Ka than aliphatic thiols(p Ka = 8.5)in the neutral conditions(PH = 7.3),thiophenol can generate more nucleophilic thiolates and display stronger nucleophilic ability,which can be easily distinguished from aliphatic thiols.As we all know,transition metal complex-based fluorescent probes not only have large Stokes shift,fluorescence quantum yield,fluorescence lifetime,but also can effectively eliminate the interference of intracellular background fluorescence,which can be used for cell imaging.Therefore,two cyclometalated iridium(III)complex-based fluorescent probe were designed and synthesized in this paper.The probes used the complexes as fluorophore and 2,4-dinitrobenzene sulfonyl chloride as recognition and quenching groups,and different properties of the probes were achieved by modifying the main ligands.In the first chapter,we introduced the research background and basis of the probe,fluorescence generation mechanism,probe structure and recognition mechanism,application and research progress of metal complexes and thiophenol fluorescent probes,and finally proposed the main research contents of the subject.In the second chapter,we designed and synthesized a luminescent probe 1oo based on photochromic cyclometalated Iridium(III)complex for high selectivity detection of thiophenol.The probe had 140 nm stokes shifts,showed excellent selectivity and sensitivity(LOD: 2.43 ?M)to thiophenol in 20% DMSO/PBS(0.01 M,p H = 7.4)solution,and the fluorescence intensity and thiophenol concentration displayed a good linear relationship in the range of 0-30 ?M.In addition,due to the introduction of photochromic diarylethene molecules into the C^N ligand as a fluorescent switch,the fluorescent recognition behavior of probes in different states can be regulated under the alternating exposure of ultraviolet and white light.In the third chapter,we designed and synthesized a water-soluble fluorescent probe based on cyclometallated iridium(III)complex for rapid detection of thiophenol.The probe introduced two polyether chains into the C^N ligand to increase the water solubility of the complex,so as to better apply to actual water samples.Probe 2 exhibits excellent selectivity and high sensitivity to thiophenol,the detection limit was 8.68×10-7 mol L-1 with a high fluorescence lifetime(?= 5.265 ?s)and the stokes shifts was 250 nm.Moreover,because of its good water solubility,the probe can be used for the quantitative determination of thiophenol in real water samples with a high recovery rate,which has certain research significance and application prospect.