The Design And Synthesis Of Novel Hg²⁺/H₂S Fluorescence Probes And Investigation Of Their Spectral Properties

Mercury ion is one of the heavy metal ions,which is highly toxic,easily absorbed and accumulated in the body.Hydrogen sulfide(H2S)is a kind of toxic gas with a stenchy odor,has recently been considered to be the third endogenous gas signaling molecule after nitric oxide(NO)and carbon monoxide(CO).Due to their environmental pollution and harmful effect to health,rapid and effective detection and identification of nitric oxide(NO)and carbon monoxide(CO)has also become a hotspot in environmental and life sciences.Fluorescent probe as a new type of detection means,is widely used in environmental analysis,cell staining,biomolecule labeling and clinical diagnosis and so on.Compared with the traditional detection and analysis methods,fluorescent probe has the advantages of high sensitivity,good selectivity,easy operation.In addition,by combining with fluorescent imaging techniques,organic fluorescent probes are not only capable of in situ and undisturbed real-time detection of one or more of the target analytes in the organism,but also can be used for monitoring both live and living biomolecules and their organisms process.Therefore,organic fluorescent probes have a broad application prospects and far-reaching academic research value in environmental monitoring,modern life sciences and disease detection and other fields.Most Hg2+ probes are limited in their application due to stability and selectivity.On the other hand,currently H2S fluorescent probes based on NBD amines are single photon excitation types,but single photon imaging has some drawbacks,such as no 3D imaging,low resolution,poor penetration,light damage and bleaching to biological samples and so on.In contrast,the use of near infrared light as an excitation light source of the two-photon probe can solve the above problems.Based on the above problems,it is important to design and synthesize new fluorescent probes which capable of quantitative detection of Hg2+ and H2S in environment and biochemistry.This paper mainly carried on the following works:In chapter 1,the research progress of fluorescence basis,fluorescence detection method,fluorescence recognition of Hg2+ and H2S are summarized.In chapter 2,we herein designed and synthesized a novel light-up fluorescent probe Lt for Hg2+ species.which is based on indole derivative and Rhodamine fluorophore.The new probe can show a linear response to Hg2+ with high sensitivity and selectivity.As the Hg2+ concentration changed from 0 to 450?M,the fluorescence intensity of L1 at 575 nm changed from 50 to 6181(?120-fold).The detection limit of the probe was 5.0 x 10-8 M.Besides,we have successfully applied probe L1 to monitor Hg2+ species in living MCF-7 cells by way of fluorescence imaging.In chapter 3,the first NBD amine based two-photon fluorescence probe L using a FRET strategy was developed for the detection of H2S in vitro and in vivo.The probe L not only afforded high selectivity and sensitivity for the detection of H2S,but also displayed a linear response to H2S with a low detection limit of 2.4×10-8 M.Furthermore,the living cell experiments indicated that this new probe L can be effective for the both exogenous and endogenous detection of H2S inside the living cells by two-photon fluorescence imaging.