Synthesis And Properties Of Novel Pyrazolone Compounds And Their Complexes With Europium And Terbium

Acylpyrazolone derivatives have been widely applied in the area ofoptoelectronic materials and life sciences because of the strong ability of coordinationand diverse ways of coordination. Thirteen novel pyrazolone derivatives have beensynthesized in this paper, and they were characterized by1H NMR,13C NMR, massspectra, elemental analysis and infrared spectra. Their complexes with Eu(III) andTb(III) were prepared, and characterized by elemental analysis, UV-Vis spectra,infrared spectra, EDTA titrimetric analysis and molar conductivity as well as thermalanalysis. The fluorescence properties and electrochemical properties of the complexeswere also studied. The main research work are as follows:(1) The1-phenyl-3-methyl-5-pyrazolone was prepared from phenyl hydrazine andethyl acetoacetate, then the1-phenyl-3-methyl-4-acetyl-5-pyrazolone was preparedfrom1-phenyl-3-methyl-5-pyrazolone and acetyl chloride using a modified Jensenprocedure. Meanwhile, the chloroacetic acid was treated with p-substituted phenol toyield the p-substituted phenoxyacetic acid, which was allowed to react with absoluteethanol, and hydrazine hydrate to get the corresponding p-substituted2-phenoxyacetohydrazide. Then a series of novel pyrazolone derivatives weresynthesized by the reaction of1-phenyl-3-methyl-4-acetyl-5-pyrazolone andp-substituted2-phenoxyacetohydrazide. Their corresponding complexes with Eu(III)and Tb(III) were also prepared. The fluorescence properties of the Eu(III) and Tb(III)complexes were investigated by fluorescence spectrometer, the results indicate that allcomplexes show the characteristic fluorescence of central ion, and the central ion isnot in the center of symmetry. The fluorescence intensity of complexes substituted bythe donative elecrton group of the corresponding ligand was increased, whereas, thefluorescence intensity of complexes substituted by the electrophilic group of thecorresponding ligand was decreased, and the fluorescence intensity of Tb(III)complexes were stronger than that of Eu(III) complexes. The fluorescence quantumyields of the title complexes were calculated by the reference method, the results showthat the complexes substituted by the donative elecrton group possess higherfluorescence quantum yield, compared with the complexes without substituent group,while the complexes substituted by the electrophilic group possess lower fluorescencequantum yield, moreover, the fluorescence quantum yields of Tb(III) complexes were higher than the fluorescence quantum yields of Eu(III) complexes. The electrochemicalproperties of the Eu(III) and Tb(III) complexes were investigated by cyclicvoltammetry, the results indicate that the HOMO energy level and LUMO energy levelof the complexes substituted by the donative elecrton group is higher than that of thecomplexes substituted by the electrophilic group.(2) The1-phenyl-3-methyl-5-pyrazolone was prepared from phenyl hydrazine andethyl acetoacetate, then the1-phenyl-3-methyl-4-chloracetyl-5-pyrazolone wasprepared from1-phenyl-3-methyl-5-pyrazolone and chloracetyl chloride using amodified Jensen procedure. Then a series of novel pyrazolone derivatives weresynthesized by the reaction of1-phenyl-3-methyl-4-chloracetyl-5-pyrazolone andp-substituted benzoic acid. Their corresponding complexes with Eu(III) and Tb(III)were also prepared. The fluorescence properties of the Eu(III) and Tb(III) complexeswere investigated by fluorescence spectrometer, the results indicate that all complexesshow the characteristic fluorescence of central ion, and the central ion is not in thecenter of symmetry. The fluorescence intensity of complexes substituted by thedonative elecrton group of the corresponding ligand was increased, whereas, thefluorescence intensity of complexes substituted by the electrophilic group of thecorresponding ligand was decreased, and the fluorescence intensity of Tb(III)complexes were stronger than that of Eu(III) complexes. The fluorescence quantumyields of the title complexes were calculated by the reference method, the results showthat the complexes substituted by the donative elecrton group possess higherfluorescence quantum yield, compared with the complexes without substituent group,while the complexes substituted by the electrophilic group possess lower fluorescencequantum yield, moreover, the fluorescence quantum yields of Tb(III) complexes werehigher than the fluorescence quantum yields of Eu(III) complexes. The electrochemicalproperties of the Eu(III) and Tb(III) complexes were investigated by cyclicvoltammetry, the results indicate that the HOMO energy level and LUMO energy levelof the complexes substituted by the donative elecrton group is higher than that of thecomplexes substituted by the electrophilic group.