Study On The Photochromic Fluorescent Photoswitching Of Naphthopyran And Oxadiazoles Chemical Sensor

From 1950 s organic optoelectric materials have attracted extensive attentions because of its unique properties and applications in many fields, such as photochromic, electroluminescent, sensor, biological imaging and memory chips. With the development of science and social progress, the demand of organic light-emitting materials with special usage is further increased. So it is of great significance to develop new organic light-emitting materials. In this dissertation, the specific contents include the following two aspects:1. We designed and synthesized of the two new photochromic fluorescent molecular switches Cz NP-SBA-15-NH₂ and PY-Cz NP-SBA-15-NH₂ with carbazole and pyrene as a fluorescence groups. The structural characteristics of compounds were measured by FTIR spectra, X-ray diffraction（XRD） and elemental analysis. Results show that naphthopyran in this two systems displayed excellent photochromic performance. The fluorescence of the compound was switched reversibly between “on” and “off” upon UV irradiation and thermal bleaching of the naphthopyran, especially in PY-Cz NP-SBA-15-NH₂ due to the photoinduced energy transfer from pyrene excimers to the opened-form naphthopyran and the photoinduced electron transfer between carbazoles and the opened-form naphthopyran moiety.2. A phosphonic acid-functionalized 1,3,4-oxadiazole fluorescent sensor has been designed and synthesized. The structural characteristics of sensor was characterized by FTIR spectra, 1H NMR and the performance of the product was studied. Results show that the synthesis of sensor in DMF-H₂ O solution can choice sex identification Fe³⁺, show the fluorescence quenching phenomenon. Other metal ions: Hg²⁺,Ni⁺,Pb²⁺,Ca²⁺,Mg²⁺,Cd²⁺,Cu²⁺,Co²⁺,Zn²⁺,Na⁺,K⁺,Mn²⁺,Ag⁺,Cr³⁺,Fe²⁺ does not affect the main compound of fluorescence spectrum. The detection limit of the sensor toward Fe³⁺ was 1 × 10^-8 M. And finally, the mechanism of sensor for the identification of Fe₃₊ was researched.