Synthesis And Properties Of Sensors Based On Near-infrared Dyes, Fluorescein Groups And Diarylethene

Copper is a necessary trace element in the human body.It plays a considerable role in many important physiological processes of the human body,such as enhancing the structure and function of proteins,maintaining the health of the central nervous system,promoting the formation of connective tissue,and protecting the body cells to avoid the injury of superoxide anion.However,high concentrations of copper are harmful to the human body because it can induce oxidative disorders and diseases related to neurodegenerative diseases such as prions,Menkes,Alzheimer’s,Wilson’s disease and Parkinson’s disease.Therefore,the development of sensors for detecting the concentration of copper in the human body is very promising.So far,some photochromic compounds,such as diarylethene derivatives,have great fatigue resistance,good thermal stability,fast response and high sensitivity due to their reversible conversion between open and closed ring forms.It is considered to be the most promising candidate for copper sensors.In general,we introduce some fluorophores or chromophores into diarylethene to synthesize novel diarylethene fluorescence sensors to detect some ions.Three kinds of diarylethenes were designed and synthesized in this paper,which realized their recognition of metal ions,acid and base by connecting different fluorophore groups.The main research contents are as follows.The first chapter introduces the background and research progress of diarylethene,near-infrared fluorescent dyes and fluorescein.as well as their application in fluorescence sensors.On this basis,our research topic is proposed.The second chapter is mainly to combine the near-infrared fluorescent dye and the diarylethene precursor to form a novel diarylethene compound 1O,and study its colorimetric and fluorescent properties.The results indicated that the compound 1O has very good photostability and photochromism.The research of ion recognition proved that the compound 1O can detect Cu²⁺and the emission wavelength of1O-Cu²⁺was in the near-infrared region.Then the mass spectrometry and nuclear magnetic resonance experiments further proved the mutual interaction between the compound 1O and Cu²⁺.In the third chapter,the fluorescein derivative was attached to the diarylethene precursor to synthesize a new diarylethene compound 2O.The UV spectrum study showed that the compound 2O had good photochromic properties and good fatigue resistance.In its in-depth study,found that the substance had only colorimetric recognition for the metal ion Cu²⁺.Therefore,we have conducted in-depth research on this aspect,and the results showed that the substance had a unique recognition of Cu²⁺.In the fourth chapter,a novel diarylethene compound 3O was synthesized by coupling a fluorescein derivative to a diarylethene precursor with salicylaldehyde by means of Schiff base.Ultraviolet spectroscopy studies showed that it had good photochromism.It was found that Cu²⁺could be identified by colorimetry and fluorescence only when the diarylethene was closed-loop state in acetonitrile solution.Therefore,we tested it under the closed-loop state of diarylethene.The Job’s plot titration experiment,nuclear magnetism and mass spectrometry were used to study the interaction between 3O and Cu²⁺.It was found that the complexation relationship between 3O and Cu²⁺was 1:1 when the diarylethene was under the closed-loop state.It was found that the complexation relationship between 3O and Cu²⁺was 1:1 when the diarylethene was under the closed-loop state.