Abstract Eight novel 1,2,4-triazolo[3,4-b][1,3,4]thiadiazole derivatives and their corresponding Eu(III) complexes were synthesized and characterized. From the spectral studies it has been concluded that the title Eu(III) complexes display six coordination. The investigation of the luminescence properties of the title complexes showed that the ligands favor energy transfers to the emitting energy level of europium ions. The title Eu(III) complexes exhibited characteristic emissions of europium ions, and possessed strong luminescence intensities, good fluorescence quantum yields, and the highest fluorescence quantum yield is up to 0.522. Furthermore, the luminescence intensity of the complex with chlorine-substituted group is the strongest than that of other complexes. The exploration of the electrochemical properties of the title complexes shows that the introduction of electron-donating groups can increase the HOMO energy levels, LUMO energy levels and the oxidation potential of the complexes, however, the result of introduction of electron-withdrawing groups was just opposite.

中文翻译：

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1,2,4-三唑并[3,4-b][1,3,4]噻二唑衍生物及其铕配合物的合成、表征及性质

摘要 合成并表征了八种新型1,2,4-三唑并[3,4-b][1,3,4]噻二唑衍生物及其相应的Eu(III)配合物。从光谱研究中得出的结论是标题 Eu(III) 配合物显示出六个配位。对标题配合物发光特性的研究表明，配体有利于能量转移到铕离子的发射能级。标题Eu(III)配合物表现出铕离子的特征发射，具有很强的发光强度，良好的荧光量子产率，最高荧光量子产率可达0.522。此外，具有氯取代基团的配合物的发光强度比其他配合物最强。