Synthesis And Properties Of Diarylethene Sensor Based On Quinoline Derivatives

The development of fluorescent sensors for ions detection has been one of the hot spots in recent years.Nowadays,many fluorescent sensors have been reported for detecting ions in environmental and biological cells.Among them,diarylethene-based fluorescent sensors have attracted the attention of many researchers because of their good photochromic properties,good fatigue resistance and thermal stability,high quantum yield and fast response,and the ability to modulate fluorescence through multiple physicochemical stimuli.Quinoline is a heterocyclic aromatic compound with one nitrogen atom,which is composed of a benzene ring and a pyridine ring.Quinoline ring system has been widely used in biomedicine and industrial chemistry.In addition,quinoline compounds,as fluorophores with high quantum yield,have attracted the interest of many researchers,and on this basis,many excellent fluorescent sensors have been designed.In the first chapter of this paper,the definition,mechanism classification and research progress of fluorescent sensors were described in detail,the research status of sensors for identifying Hg²⁺,Zn²⁺,Cd²⁺were briefly summarized,the advantages of quinoline compounds as fluorescent sensors were briefly discussed and exemplified.Finally,the porperties of diarylethene photochromic compounds and their recognition in ions,p H and amino acids were discussed in detail.On this basis,the research topic of this paper were put forward,three cationic fluorescent sensors with similar structures but completely different properties were obtained by a simple condensation reaction using diarylethene-based compounds and quinoline derivatives.In the second chapter of this paper,a quinoline derivative containing a benzothiazole structure was linked to a diarylethene-containing benzaldehyde group to obtain a fluorescent chemosensor 1o that can specifically recognize Hg²⁺.The photochromic and anti-fatigue properties of 1o in acetonitrile solution were investigated,ion selectivity and anti-interference experiments of 1o were conducted,the complexation ratio,detection limit and binding constant of 1o and Hg²⁺were calculated,and finally,1o was used to construct a logic circuit.In the third chapter of this paper,the Zn²⁺fluorescent chemosensor 2o was obtained by linking a quinoline derivative containing a pyridine ring with a diarylethene-containing pyridine aldehyde group through a simple schiff base reaction,and the photochromic and fluorescent properties of 2o in tetrahydrofuran solution were investigated.The reaction mechanism and binding mode were inferred by ¹H NMR ion titration and ESI-MS mass spectrometry,and finally 2o was applied to real water sample detection and test strip detection.In order to further investigate the effect of different diarylethenes parts on the recognition of metal cations,in chapter 4 of this paper,based on 2o,the diarylethene Cd²⁺fluorescent chemosensor 3o with similar structure but different properties was obtained by modifying the diarylethene parts by replacing the pyridine aldehyde group with the phenyl aldehyde group,which was linked to the same quinoline fluorophore,and its structure was characterized by ¹H NMR,¹³C NMR and ESI-MS,the sensing mechanism of 3o to Cd²⁺was systematically investigated.Finally,3o was used to construct a logic circuit and detection of Cd²⁺in real water sample.