Design And Synthesis Of Naphthyridylfluoresce Probes And Their Performance Research

Cysteine, homocysteine and glutathione are three vital thiols in human body, and the abnormal level of them in living systems will induce a number of physiological diseases. Thiophenols, often mentioned in environmental science, though have great value in the industrial application, are classified as highly toxic compounds. Thus, the design and synthesis of probes with high sensitivity and high selectivity to identify compounds which contain -SH has become the research focus in supramolecular host-guest chemistry in recent years.Recent years, biological thiols reactive fluorescent probes have been widely reported, among which are the probes based on the mechanism of nucleophilic aromatic substitution. Selecting fluorophore such as rhodamine, cyanine, coumarin, fluorine, boron-dipyrromethene,etc., researchers design and synthesize a series of fluorescent probe of excellent fluorescence properties with the fluorescence-quench method through the nucleophilic substitution of the 2,4-dinitrofluorobenzene or 2,4-dinitrophenyl chloride. The naphthyridine compounds are in macrocyclic conjugated system. They have large Stokes shift and are easy to synthesize, thus making them also an excellent fluorophore to be used to synthesize the fluorescent probe. But the reviewing of the literature background reflects that few previous researches mentioned fluorescent probes with the naphthyridine derivatives as fluorophore based on the aromatic nucleophilic substitution mechanism. So, we designed and synthesized a series of fluorescent probes with 2,7-naphthyridine derivatives as fluorophore, and have studied their spectral properties and practical application possibilities. This thesis will mainly go into two parts:The first part will briefly introduce the fluorescence probe technology, and summarize the development and prospect of fluorescent probe based on the nucleophilic aromatic substitution mechanism, thus putting forward the main idea of this paper.The second part will show the experiment we conducted. Through the thiols selective cleavage of the 2,4-dinitrophenyl functionality, we have designed and synthesized a series of fluorescent probes with the derivatives of 2,7-naphthyridine as fluorophore, and have confirmed the structure of these probes by NMR, IR and HR-MS spectroscopy. We use UV absorption spectra and fluorescence spectra to detect their selective recognition ability, and find that, under mild conditions, these probes can identify thiophenols and biological thiols with high selectivity and high sensitivity, and their Stokes shift can be up to 142.5 nm. The experimental results show that fluorescent probe 2-6 can quantitatively and selectively detect the concentration of thiophenol in the water samples, and fluorescent probe 2-7 can identify biological thiols in a low dose. And the detection limit of probe 2-7 for glutathione is found to be about 0.31?M. Furthermore, the product of the separation and purification of the probe solution with either thiophenol or biological thiol proves that the reaction mechanism is the aromatic nucleophilic substitution reaction mechanism, exactly consistent with our design. Thus, it could be concluded that the derivatives of naphthyridine are a class of outstanding thiophenol and biological thiol fluorescent probes, and the research of their practical application will be further studied.