Synthesis And Application Of Fluorescent Probe For Intramolecular Redox Substance Detection

In complex life system,many substances jointly maintain the homeostasis,a dynamic process.The dynamic equilibrium of the redox state plays an important role in maintaining the normal metabolism of cells.Therefore,it is very important to detect the thiols and reactive oxygen species?ROS?in the cells.Meanwhile,the design of novel fluorescent molecular probes has positive impact on the relevant physiological and pathological research.With the development of fluorescence imaging,the method of fluorescent spectroscopy detection is widely used in analytical chemistry,especially in biological analysis.Characterlized by rapid response,high sensitivity,excellent selectivity,small injury and real-time implementation,fluorescence probes provide an effective way to research on visualization of cellular metabolism and molecular pathogenetic mechanism.In this paper,based on the mechanism of internal charge transfer?ICT?,five dicyanoisophorone-based probes were synthesized for detecting thiol compounds,hypochlorite and heavy metals,respectively.All probes exhibited satisfactory spectral properties,and can be used for cell imaging.In chapter 2,based on boric acid and phenothiazine,two colorimetric ClO^--selective chemsensor,T1 and T2,were designed and synthesized,respectively.The emission of probe T1 located within near-infrared region,which provide the possibility for in vivo imaging.The probe T1 showed a large Stocks shift?145 nm?and wide pH detection range?4.0-11.0?.The probe T2 is synthesized using the S atom in phenothiazine as a reaction site for HClO/ClO^-.T1 featured fast-response towards HClO/ClO^-,with a low detection limit of 10-8 M.Confocal fluorescence microscopy experiments demonstrated that T2 could be applied for the live-cell imaging of both exogenous and endogenous HClO/ClO^-.In chapter 3,two fluorescent probes,X1 and X2,were designed and synthesized for detection thiols by using 2,4-dinitrobenzenesulfonyl and NBD-Cl as the recognition groups,respectively.The result indicated that the fluorescent probe X1 showed good selectivity towards GSH,Cys,Hcy and NAC in PBS/ethanol solution,and a low detection limit of 10-8 M was achieved.At the same time,in the presence of thiols,probe X1 exhibied a large Stokes shift of 157 nm.Compared with the probe X1,the fluorescent probe X2 possessed higher selectivity for Hcy in the HEPES/ethanol system and can be used to monitor intracellular Hcy.In chapter 4,based on the chalcophile affinity and coordination characteristics of Hg²⁺,we designed and synthesized a fluorescence probe H1 for Hg²⁺.Probe H1 showed a visible colorimetric change from red to yellow,leading to “naked-eye” of Hg²⁺.Experiment showed that probe H1 can detect Hg²⁺ reversibly and can be used to monitor Hg²⁺ in cells.