稀土与邻香兰素二胺类双Schiff碱配合物合成及其性质的研究

Studies on Coordination Compounds of Rare Earth Nitrates with Bis-schiff Bases Derived from o-Vanillin and Some Diamines

在非水体系中首次合成了硝酸稀土(Ⅲ)的邻香兰素(2-羟基-3-甲氧基苯甲醛)与乙二胺(L^1)、联苯胺(L^2)、邻苯二胺(L^3)和间苯二胺(L^4)的双Schiff碱配合物(1—8).通过测定红外光谱、摩尔电导、X射线衍射和X射线光电子能谱推断了配合物的结构和键合情况,配合物的中心金属离子与配体中的二个氮原子、二个氧原子和二个硝酸根中的四个氧原子配位,其配位数为8.通过热重及差热分析发现配合物在低于230℃时很稳定,对于同一配体与不同中心金属离子形成的配合物来说,其热稳定性随稀土离子半径的减小而降低.在77K时测试了铕配合物的激发光谱和荧光光谱,观察到Eu^(3+)的特征发射峰.

The coordination compounds between rare earth nitrates and big-Schiff bases derived from o-vanillin (2-hydroxy-3-methoxy-benzaldehyde) and ethylenediamine, benzidine, o-phenylenediamine, m-phenylenediamine were synthesized in non-aqueous system. The Schiff bases are indicated as L^1, L^2, L^3, L^4 respectively. The compositions of the coordination compounds have been given by elementary analysis to be LnL(NO_3)_3 (L=L^1, Ln=La, Ce, Eu; L=L^2, Ln=La, Tb; L=L^3, Ln=La, Eu; L=L^4, Ln-La). The coordination modes of the bonding in these compounds were given on the basis of infrared spectra, molar conductance, X-ray powder diffraction analysis, X-ray photoelectron spectra studies. Their possible structures were proposed. Two nitrogen atoms and two oxygens in a ligand, four oxygen in two nitrate groups are bound to a rare earthion. The lanthanide ions in the coordination compounds exhibit eight coordination numbers. The thermal analytioal results indicate that the coordination compounds are stable up to 230℃. The thermal stability of the coordination compounds for the same ligands increases with decrease of lanthanide ionic radius. The excitation and fluorescent spectra of Eu (Ⅲ) coordination compounds were also measured at 77 K. The characteristic emission peak of Eu^(3+) was observed.