Two novel ESIPT benzothiazol derivatives and corresponding europium(Ⅲ) complexes: Synthesis and fluorescent properties

摘要

Two ESIPT benzothiazol derivatives and corresponding europium complexes were synthesized and characterized by the (HNMR)-H-1 spectrum, Mass spectrum, Elemental analysis, UV-Vis analysis, Molar conductivity, Thermogravimetric analysis and FTIR analysis. The fluorescence intensity of the ligands and complexes are compared, and the fluorescence quantum yields are also calculated by the reference method. The results show that two ligands emit orange fluorescence due to the ESIPT process, but both complexes emit red fluorescence after coordinating with Eu3+. Compared with the ligands, the fluorescence intensity and fluorescence quantum yield of the complexes are enhanced, and the monochromaticity is also improved. Because of the stable tetra-dentate coordination, the fluorescence intensity of EuL7(NO3)(3)center dot 2H(2)O is the strongest, and EuL7(NO3)(3)center dot 2H(2)O EuL6(NO3)(3)center dot 2H(2)O Ligand 6 Ligand 7, so does the fluorescence quantum yields. The electrochemical properties of the complexes show that the HOMO energy level of EuL7(NO3)(3)center dot 2H(2)O is higher than that of EuL6(NO3)(3)center dot 2H(2)O, but LUMO energy level is lower than that of EuL6(NO3)(3)center dot 2H(2)O. These ligands and complexes have potential applications in the field of life sciences and optical materials.