铕镧苯甲酸α,α′-联吡啶配合物的合成及性质研究

在乙醇介质中合成了以Eu3+ 和La3+ 为中心体、苯甲酸和α ,α′ 联吡啶为配体的混合稀土配合物。测定了配合物的组成、研究了其紫外光谱和红外光谱。结果表明 ,配合物的组成为EuxLa1 -x(Dipy)L3·H2 O ,苯甲酸和α ,α′ 联吡啶的紫外吸收峰在配合物中分别位移了 2～ 9nm ;苯甲酸根羧基的反对称伸缩振动和对称伸缩振动在配合物中向低波数移动 ,而α ,α′ 联吡啶的CN振动则向高波数移动。这些事实表明 ,苯甲酸和α ,α′ 联吡啶与稀土离子配位。荧光测试表明 ,用不发光的镧离子取代该系列配合物中部分铕离子 ,在一定范围内 ,可以提高三价铕的特征荧光发射强度。这一结果也表明 ,在该系列配合物中 ,不仅配体可以将吸收的能量传递给发光的铕离子 ,使其发光 ,而且不发光的镧配合物也可将其吸收的能量通过分子内能量传递给铕离子 ,增强铕的发光强度。

Synthesis and Characterization of Eu(La) Complexes with Benzoate and α,α′-dipyridyl

A series of dinuclear complexes of different molar ratio of Eu3+ to La3+ with benzoate and alpha,alpha'-dipyridyl have been synthesized in the anhydrous alcohol. Their composition was RE(Dipy)L3.H2O (RE = Eu3+ and La3+, L = C6H5COO-). Their UV spectra and IR spectra were studied. The UV absorption spectral peaks of benzoic acid and alpha,alpha'-dypyridyl shifted 2-9 nm in the complexes. The characteristic anti-symmetric and symmetric stretching vibrations of carboxylate group shifted to lower frequency, while the C=N stretching vibrations shifted to higher frequency in the complexes. These situations show that chemical bonds have formed between the ligands and the rare earth ions. The fluorescence spectra of the complexes were investigated, and the results indicate that the fluorescence emission intensity of europium ion was sensitized by lanthanum ion in the complexes. These facts show that not only the ligands but also the lanthanum complex can transfer the absorbed energy to Eu3+ ion in the complexes.