Design And Synthesis Of The Novel Fluorescent Probes Of HClO/H₂S And The Investigation Of Spectral Properties

Recently, fluorescence imaging method is particularly appealing because of its excellent selectivity, high sensitivity, simplicity of operator, real-time quantitative detection, non-invasive detection,and monitoring biomolecules within the context of living systems with high spatial and temporal resolution. In biological systems, features of physiologically active species have low concentration, high reactivity a nd short lifetimes, it still remains a huge challenge to determine the intracellular concentration of these species accurately. In order to meet these urgent needs, reaction-based fluorescent probes have emerged. And therefore, it's very significant to synthetize fluorescent probe with high selectivity and sensitivity in the native biological environment.In this paper, the second chapter firstly introduces a new type of the ratiometric fluorescent probe used for the detection of HCl O. The probe is based on the structure of the merocyanine fluorophore, by the mechanism of intramolecular charge transfer(ICT) and then synthesized by chemical modification. This ratio fluorescence probe showed a ratiometric fluorescent response to hypochlorite with the emission intensities ratio(I579nm/I621nm) increasing from 0.2 to 1.5, so it has a good ratio of fluorescence detection effect, largely reducing the interference of background factors. Furthermore, the probe displayed high selectivity for hypochlorite over other s pecies. The spectrum of the probe has good performance, high selectivity and sensitivity, short reaction time and so on features, it is possible to detect environment and biology hypochlorous acid in the future.In the third chapter, we have introduced a high water-soluble hydrogen sulfide fluorescent probe based naphthalimide chromophore with a hydrophilic alcoholic group. We employed the naphthalimide chromophore as the signal reporter and azido group as the responding site for H2 S to construct a H2 S probe based on internal charge transfer(ICT) process. The probe exhibits a marked turn-on fluorescence signal(7.9-fold) for responding to hydrogen sulfide via internal charge transfer switching mechanism. We employed standard NMR, mass spectrometry and time-dependent density function to validate the responding mechanism. It has a selectivity and sensitivity for in vitro hydrogen sulfide over other various biologically relevant species, and could also detect both the exogenous and endogenous hydrogen sulfide in living cells. So, probe Nap-N3 might be employed as a turn-on fluorescent probe for detecting H2 S.