铕与三种不同结构羧酸配合物的低温固相合成及发光性能研究

Synthesis of Three Different Structural Aromatic Carboxylic Acid Complexes with Europium with Solid State Reaction at Low Temperature and Studies on Luminescence Property

以共轭体系大小不同、配位基团与共轭体系的距离不同的三种羧酸:1-萘甲酸、苯甲酸、苯乙酸和氯化稀土为原料,采用低温固相反应合成了三种羧酸铕配合物。经元素分析、稀土络合滴定、摩尔电导确定了配合物的组成为:Eu(L1)3,Eu(L2)3.1.5H2O,Eu(L3)3.1.5H2O(L1=C10H7COO-,L2=C6H5COO-,L3=C6H5CH2COO-)。测定了配体及配合物的的IR谱、1HNMR谱及配体的磷光光谱和铕配合物荧光激发和发射光谱。根据磷光发射光谱数据计算了配体的三重态能级值。三个配合物的荧光发射主峰5D0→7F2强度按萘甲酸铕>苯甲酸铕>苯乙酸铕的顺序变化,由此可见配体的结构不同对铕离子的发光将产生很大的影响。

solid complexes of europium with 1 -naphthoic acid （L1）,benzoic acid （L2） and phenylacetic acid （L3） have been synthesized by method of solid state reaction at low temperature. Elemental analysis, rare earth coordination titration studies suggest that the compositions of the complexes are Eu（L1 ）3, Eu（L2）3·1.5H2O, Eu（L3 ）3·1.5H2O respectively. IR spectra and ：HNMR studies indicated that the coordination fashion of three ligands with Eu（ Ⅲ ） is different. The ligand（L1） is bonded with Eu （Ⅲ ） by two oxygen atoms in carboxyl group which coordinate as an asymmetrical bridging bidentate group. The ligand（L2） is bonded with Eu （ Ⅲ ） by two oxygen atoms in carboxyl group which coordinate as a chelate - bridging tridentate group. The ligand（L3 ） is bonded with RE（ Ⅲ ） by two oxygen atoms in carboxyl group which coordinate as a symmetrical chelate bidentate group. The Molar conductivity in DMSO solvent indicates that all complexes are non- electrolyte. Fluorescence spectra of complexes and phosphorescence spectra of ligands show that all of three ligands have sensitized differently Eu^3＋ in fluorescence intensity. It indicates that the triplet state energy of ligands and the different structure play an important role in luminescence of complexes. Fluorescence intensity of three complexes is Eu（L1）3 〉 Eu（L2）3· 1.5H2O 〉 Eu（L3）3·1.5H2O. So structure of carboxylic acid has an effect on Eu^3＋ luminescence in this complexes.