均苯三甲酸铕掺杂配合物的合成及其荧光性能

合成了两个系列的均苯三甲酸铕配合物。其一是以均苯三甲酸(H3btc)为配体,Eu3+及掺杂过渡金属Zn2+、Cd2+、Mn2+、N i2+为中心离子的配合物;其二是以均苯三甲酸、邻菲啰啉(Phen)为配体,Eu3+及掺杂Y3+、La3+、Gd3+为中心离子的异核稀土配合物。对配合物进行了元素分析、差热-热重、红外光谱、紫外光谱、荧光寿命及荧光性能等方面的测试分析。配合物的组成分别为:EuL.6H2O(1)、EuLL1.′5.2H2O(2)、Eu0.5Y0.5LL1.′5.3H2O(3)、Eu0.5La0.5LL1.′5.3H2O(4)、Eu0.5Gd0.5LL1.′5.3H2O(5)、EuZnLC l2(C2H5OH)2.2H2O(6)、EuCdLC l2-(C2H5OH)2.5.2H2O(7)、EuMnLC l2(C2H5OH)2.2H2O(8)、EuN iLC l2(C2H5OH)2.2H2O(9)(其中L=btc,L′=Phen)。均苯三甲酸的羧酸氧原子和邻菲啰啉的氮原子与稀土离子配位。差热-热重的测试结果表明,均苯三甲酸-邻菲啰啉异核稀土配合物的分解温度为490℃,铕掺杂过渡金属配合物分解温度为450℃,两类配合物的最终分解产物均为氧化物。荧光光谱的测试结果表明,三元配合物EuLL1.′5.2H2O(2)的荧光强度明显高于二元配合物EuL.2H2O(1);配合物(3)、(4)、(6)、(7)中,Y3+、La3+、Zn2+、Cd2+无未充满的d层或f层电子,对Eu3+的荧光有增强作用;配合物(5)中的Gd3+有4 f7半充满稳定电子层结构,对Eu3+的荧光也有增强作用。在配合物(8)和(9)中,Mn2+和N i2+的未充满d层电子消耗配体吸收的能量,对Eu3+的荧光有猝灭作用。

Synthesis and Fluorescence Properties of Doped Europium Benzene-1, 3,5-tricarboxylate Complexes

Nine doped europium benzene-1,3,5-tricarboxylate complexes have been synthesized and characterized. Elemental analysis, rare earth coordination titration, IR spectra, UV absorption spectra and TG-DTA were used to characterized these complexes. The studies of the fluorescence spectra and lifetimes of the nine complexes show obviously difference. Compared with binary complex of EuL·6H2O(1), the ternary complex EuLL'1.5·2H2O exhibits stronger luminescence intensity. This result indicates that the fluorescence intensities of the complexes depend on ligands. In the binary complex the ligand (btc) transfers some energy to Eu3+, but in ternary complexes both the ligands (btc and phen) transfer more energy. The fluorescence peak positions of the other seven are similar to (1) and (2), but the luminescence intensities of these complexes are obviously different. The positions of Eu3+ emission peak of the complexes do not change, indicating that the introduction of doped rare earth ions or transition-metal ions does not influence the energy level of Eu3+ in the complexes. The dinuclear complexes, which contain the metal ions Y3+, La3+, Zn2+ and Cd2+ without unsa-turated d-layer or f-layer electrons, display sensitization and strengthening to fluorescence properties of those complexes, respectively. Therefore, the energy absorption by organic ligands will not be consumed by the d-d or f-f transfer. In this manner, Eu3+ absorbs much more energy through intramolecular energy transfer and luminous intensity is enhanced. Gd3+ has inert half-full 4f7 electronic configuration, so the luminous intensity of (5) is also strong and similar with (3) and (4). Complexes (8) and (9), containing Mn2+ and Ni2+, respectively, exhibit fluorescence quenching, which is caused by the unsaturated d-layer electrons consuming the energy in the form of radiative transition.