Synthesis And Properties Of Novel Pyrazolone And Coumarin Derivatives And Their Complexes With Europium And Terbium

Pyrazolone and coumarin derivatives have been widely applied in the area of luminous functional materials and biomedical sciences because of their serious active coordination center, diverse ways of coordination and excellent optical activity. Seven novel pyrazolone derivatives and seven novel coumarin derivatives have been designed and synthesized in this paper, and they were characterized by 1H NMR,13H NMR, mass spectra, elemental analysis ultraviolet spectra and infrared spectra. Their complexes with Eu3+ and Tb3+ were prepared successfully, and characterized by elemental analysis, EDTA titrimetric analysis, molar conductivity, ultraviolet spectra and infrared spectra as well as thermal analysis. The fluorescence properties and electrochemical properties of the complexes were also studied. The main research work are as follows:(1) The intermediate 1-phenyl-3-methyl-4-acetyl-5-pyrazolone was prepared from 1-phenyl-3-methyl-5-pyrazolone and acetyl chloride using a modified Jensen procedure; meanwhile, the chloroacetic acid was treated with p-substituted phenol to yield the p-substituted phenoxyacetic acid. Then a series of novel pyrazolone derivatives were synthesized by the reaction of 1-phenyl-3-methyl-4-acetyl-5-pyrazolone and p-substituted phenoxyacetic acid. Their corresponding complexes with Eu3+ and Tb3+ were also prepared. The fluorescence properties of the title complexes were investigated in detail, the results showed that all the title complexes exhibited characteristic emissions of Ln3+ ion and the central ion is not in the center of symmetry. The introduction of electron-donating groups can increase the luminescence intensity of the title complexes; but electron-withdrawing group conversely. Moreover, the fluorescence properties of Tb3+ complexes were better than that of title Eu3+ complexes, and the luminescence intensity of the complex with chlorine substituent is the strongest. The research results of fluorescence quantum yields of the title complexes show that the introduction of the electron-donating group in the ligands can increase the fluorescence quantum yields of the title complexes; but electron-withdrawing group conversely. The electrochemical properties of the title complexes were investigated by cyclic voltammetry, the results indicate that the oxidation potential and LUMO energy level of the title complexes with electron-donating group were higher than that of the title complexes with withdrawing groups, but the HOMO energy level were more lower.(2) The intermediate 7-hydroxy-4-methyl-8-formyl coumarin was prepared from hydroxy-4-methylcoumarin and hexamine; Meanwhile, the chloroacetic acid was treated with p-substituted phenol to yield the p-substituted phenoxyacetic acid derivatives, which was allowed to react with absolute ethanol, and hydrazine hydrate to get the corresponding p-substituted 2-phenoxyacetohydrazide derivatives. Then a series of novel coumarin derivatives were synthesized by the reaction of 7-hydroxy-4-methyl-8-formyl coumarin and p-substituted 2-phenoxyacetohydrazide. Their corresponding complexes with Eu3+ and Tb3+ were also prepared. The fluorescence properties of the title complexes were investigated, the results showed that all the title complexes exhibited characteristic emissions of Ln3+ ions and the central ion is not in the center of symmetry. The introduction of electron-donating groups can increase the luminescence intensity of the title complexes; the introduction of electron-withdrawing groups can decrease the luminescence intensity of the title complexes. The research results of the fluorescence quantum yields of the title complexes show that introduction of the electron-donating group in the ligands can increase the fluorescence quantum yields of the title complexes; the introduction of the electron-withdrawing group in the ligands can decrease the fluorescence quantum yields of the title complexes. The research results of the electrochemical properties of the title Eu3+ complexes indicate that the introduction of electron-donating groups can increase the oxidation potential, decrease the HOMO energy level and LUMO level, but the introduction of electron-withdrawing groups can decrease the oxidation potential, but increase the HOMO energy level and LUMO level. The research results of the electrochemical properties of the title Tb3+ complexes shows that the oxidation potential of the title complexes with electron-donating groups are higher than that of the complexes with electron-withdrawing groups, but the HOMO energy level and HOMO energy level were more lower.