The Studies Of Synthesis And Properties Of Diarylethene Derivatives Based On The Pyridine Functional Group

In recent years,the research on photochromic functional materials has been becoming increasingly popular owing to their potential applications as sensors,photoresponsive self-assemblies,optical memory storage,live cell imaging,molecular logic gates,and multifunctional switches.Among diverse photochromic compounds,diarylethene derivatives are the most promising candidate photochromic system because of their fast response,excellent thermal stability and outstanding fatigue resistance.Due to the distinct feature,an increasing number of diarylethenes with various functional groups have been extensively developed.In this thesis,nine novel diarylethenes which contain a pyridine functional group were designed and synthesized.Photochromism,metal ions recognition,sequential detection,acid/base effects and weak intramolecular interactions of the diarylethenes were systematically studied.The main contents and results are generalized as follow:1.The research status and main parameters of diarylethene derivatives have been given,the recent progress of photochromic materials was reviewed,and the target of our research was brought out.2.2,6-di?thiazol-2-yl?pyridine was connected to diarylethenes by typical Sonogashira reaction for the first time.The diarylethenes exhibited good photochromic properties in solution.The studies showed that DTE-1 can be used as a dual-control fluorescent molecules switch by Cd²⁺/Zn²⁺and optical.3.Two diarylethene derivatives containing pyidne-quinoline were synthesized by Williamson reaction.Their strctures are nearly the same,but the properties of fluorescent switch and ion recognition are quite different in acetonitrile.DTE-3exhibited remarkable fluorescent switch and high sensitivity and selectivity for the detection of ions in solution.Moreover,apart from modulating by Cd²⁺and light,DTE-3 also can be modulated by TFA/TEA.4.Diarylethene derivatives containing pyidne-benzothiazole/benzimidazole were synthesized by condensation reaction.DTE-5 showed an excellent sequential selectivity for Fe³⁺and cysteine in methanol for the first time.In the presence of Fe³⁺,the fluorescent chemsensor diarylethene would form Fe³⁺complex,which induces a dramatic fluorescence quenching.Subsequently,the chemosensing ensemble Fe³⁺complex was used as a fluorescent turn-on chemosensor for cysteine.The results showed that DTE-6 can be used as a ratiometric fluorescent chemosensor for the detection of Zn²⁺and Al³⁺,and can be used as a pH fluorescent chemosensor.The fluorescent intensity after stimulating by ions and pH can be modulated by light continued.5.Three novel diarylethene derivatives containing pyridine and heteroaryl were synthesized via Suzuki and Stille crossing-reaction.The results showed that diarylethenes with thienyl/thiazyl unit showed higher photocyclization quantum yield than that with phenyl moiety,which was ascribed to the existing weak F···N and N???S heteroatom-contact.The potential F···N contact improved the cyclization quantum yield from the conformational aspect,while S···N contact enhanced the cyclization quantum yield from the energetic aspect.