Synthesis And Properties Of Diarylethenes Molecular With The Nitrogen Atom

Among organic photochromic materials, diarylethenes are one of the most promising candidates for practical applications because of their remarkable fatigue resistance, excellent thermal stability, and rapid response to the stimulation of light and chemicals. Until now, fluorescent diarylethenes have attracted great interest for the application of the nondestructive optical readout system. Most of these diarylethenes show turn-off fluorescence change due to the formation of non-fluorescent closed-ring isomers upon light stimulus. A challenge in the development of fluorescent diarylethenes is to design a sensitive multi-responsive fluorescent diarylethene molecule. Therefore, eight new molecular structures have been designed and their photochemical, acid/base properties and metal ion recognition were investigated systematically. The main content of this paper summarize as follows:In chapter 1, the research background, properties and application in chemical and biological fields of diarylethene compounds are briefly introducted. Their application in fluorescent switch is intensively introduced.In chapter 2, three diarylethene compounds DT-1-3 based on quinoline moiety were synthesized, and they showed good photochromism in acetonitrile, PMMA films and crystal structure. Photochromism, acidichromism, and fluorescence of them were investigated systematically to discuss the effect of the heteroaryl rings.In chapter 3, three asymmetric piperazine-1,8-naphthalimide-tethered diarylethene molecules DT-4-6 were synthesized. Intramolecular photoinduced electron transfer (PET) from piperazine to naphthalimide was happened due to the N atom in piperazine moiety, which makes the fluorescence quenched. The PET effect was efficiently blocked by protonation and metal ions, consequently the strong fluorescence of 1,8-naphthalimide moiety resumed.In chapter 4,1,8-naphthalimide was connected to diarylethenes by Click reaction to synthesize two diarylethene molecules DT-7-8. Comparing their photochemical properties with compounds DT-4-6 analysed the complexing loci of diarylethenes with metal ions.