Synthesis And Study Of Phenylthiophenol Fluorescent Probes Based On Metal Complexes

Sulfhydryl compounds include aliphatic mercaptan and aromatic thiophenol,which are important substances in chemical industry and biological system.Cysteine,homocysteine and glutathione in aliphatic mercaptan play an important role in physiological regulation.Aromatic thiophenols are highly toxic to organisms and volatile easily.They not only smell bad,but also have a serious impact on human physiology and psychology.Long-term exposure to thiophenol may cause central nervous system injury,dyspnea,muscle weakness,limb paralysis,coma,and even death.Therefore,it is of great significance to develop specific detection methods for thiophenol in environmental and biological samples.At present,methods such as high performance liquid chromatography,gas chromatography,non-linear spectroscopy and sensor based on nanomaterials can be used to detect the concentration of thiophenol.However,these methods have complex sample pretreatment,low sensitivity,susceptibility to interference,expensive instruments and can not be real-time online monitoring.Fluorescent probe detection has attracted wide attention because of its simple operation,rapid response,high sensitivity and selectivity,as well as its direct detection in living cells or tissues.However,aliphatic mercaptan and aromatic thiophenol are difficult to distinguish because of their similar chemical structure and poor selectivity.Therefore,it is a great challenge to design fluorescent probes that can distinguish aliphatic thiols from aromatic thiols.Fortunately,under neutral conditions,the pKa values of thiophenol and aliphatic thiols are 6.5 and 8.5,respectively,which provides a method for distinguishing thiophenol from aliphatic thiols.At present,many thiophenol fluorescent probes have been reported at home and abroad,but most of them are organic small molecule fluorescent probes.Complexes have the advantages of high luminescence efficiency and large Stokes displacement.They can be designed as fluorescent probes to identify thiophenol.Two new metal complexes thiophenol fluorescent probes,were designed and synthesized.The complexes were used as fluorescent groups,2,4-dinitrobenzenesulfonyl groups were linked as recognition groups,and the complexes were functionalized bymodifying ligands.The sensitivity and selectivity of fluorescent probes to thiophenol were systematically tested,and the recognition mechanism of fluorescent probes to thiophenol and its application in water samples were discussed.In the first chapter,we introduce the harm of Thiophenol and the significance of detection,the advantages and mechanism of fluorescent probes,the research situation of metal complexes and the research progress of Thiophenol fluorescent probes.Finally,the main contents of the study are put forward.In the second chapter,we synthesized an iridium complex thiophenol fluorescent probe 1 containing triphenylpyridine ligand.Probe 1 has good sensitivity and selectivity to thiophenol in 20% DMSO/PBS solution,and the response time to thiophenol is faster.The fluorescence increases six times when recognition is complete,and it can quantitatively detect thiophenol in water samples.In the third chapter,we synthesized an iridium complex thiophenol fluorescence probe 3 containing larger ? conjugated ligands.The fluorescence emission peak of probe 3 changed red after reacting with thiophenol completely in 50% DMSO/PBS solution.The fluorescence increased by 8.4 times.It has good sensitivity and selectivity to thiophenol and has been successfully applied to the quantitative determination of thiophenol in water samples.