Preparation Of Fluorescence Materials With Photochromic Property And Sensing Performance Based On Schiff Base

In recent years,fluorescence materials,fluorescent and colorimetric sensing materials,photochromic and piezochromic materials have attracted more and more attention,they have great potential applications in chemistry,biology and physics.Optical materials have been widely used in many fields,especially stimulus responsive materials and chemical sensing materials,which have attracted extensive attention.In this paper,using Schiff base as the bonding group,naphthol pyran and benzene lipids were combined with diaminomaleic eye respectively to construct the materials with photochromic,piezochromic and chemical sensing properties.The molecular structure of the material was clearly characterized by NMR and MS,and the properties of the material in coloration and chemical sensing were studied by spectral test.The results show that the material has photochromic,piezochromic and chemical sensing properties.In the first part,a novel compound（NPDL）was designed and synthesized by Schiff base combining naphthopyrane group with diaminomaleic point.Its molecular structure was characterized by nuclear magnetic resonance spectroscopy（NMR）and mass spectrometry.UV-Vis absorption spectra show that NPDL has excellent photochromic properties,photochromic reversibility and fatigue resistance.The ring-opening structure of naphthopyran leads to the increase of the conjugation degree of NPDL molecules,thus enhancing its fluorescence.When the naphthopyran is closed,the fluorescence intensity returns to the closed-loop state.Therefore,the fluorescence intensity of NPDL can be regulated through the isomerization reaction of naphthopyran,making it have the properties of photochromic fluorescence switch.At the same time,NPDL exhibited high selective colorimetric sensing and fluorescence sensing performance for copper ions,with a wide linear range and a very low detection limit.The detection limits of colorimetric sensing and fluorescence sensing were 5.39×10^-4 mol/L and 4.03×10^-6 mol/L,respectively,and the fluorescence switching performance.The selective optical sensing ability of NPDL for copper ions can be attributed to the characteristic of NPDL for selective fluorescence coordination of copper ions.The fluorescence imaging results of biological cells showed that NPDL also had the ability to recognize the presence of copper ions in biological cells.NPDL has good performance in photochromic and chemical sensing,and has potential application prospects.In the second part,a novel molecule（ACMH）was constructed by combining the benzene lipid group with diamino-maleonitron by using Schiff base as the linker,and its molecular structure was characterized by NMR spectroscopy.Fluorescence spectra before and after grinding showed that ACMH had good piezochromic properties.The results of IR spectrum and XRD powder diffraction show that the piezochromic change is caused by the interaction between molecules and the change of crystal structure before and after grinding.ACMH also shows the potential application in anti-counterfeiting.ACMH also has the ability of selective fluorescence sensing for copper ions.