镧系—β—二酮—有机碱三元体系中f—f跃迁导数吸收光谱的研究

DERIVATIVE SPECTROPHOTOMETRIC STUDY ON LANTHANIDES-β-DIKETONES-ORGANIC BASES TERNARY SYSTEMS

本文系统地研究了Pr^(3+)、Nd^(3+)、Sm^(3+)、Eu^(3+)、Dy^(3+)、Ho^(3+)、Er^(3+) 及Tm^(3+)八种离子在乙醇介质中与乙酰丙酮(AA)、苯甲酰丙酮(BA)、二苯甲酰甲烷(DBM)及噻吩甲酰三氟丙酮(TTA)等β-二酮形成的二元配合物及由它们与二苯胍(DPG)、1,10-邻菲咯啉(pben)所形成的三元配合物在可见光区的吸收光谱和高阶导数吸收光谱。结果表明,以导数吸收光谱研究f-f跃迁具有较高的灵敏度和分辨率。确定了两类三元配合物的组成为Ln^(3+):β-二酮:DPG=1:4:1,Ln^(3+):β-二酮:phen=1:3:1,根据吸收峰的位移,计算了配合物的共价参数。指出混配配合物具有明显的共价性。比较了配合物的稳定性与原子序数之间的关系,观察到了明显的双峰效应。

The absorption spectra and derivative spectra of binary complexes of the trivalent lanthanides (Ln = Pr. Nd, Sm, Eu, Dy, Ho, Er and Tm) with β-diketones such as acetylacetone(AA), benzolacetone(BA), dibenzolmethane(DBM) and 2-thenoyl trifluoroacetone(TTA),and ternary complexes of binaries with organic bases diphenylguanidine (DPG) and 1, 10-phenanthroline (phen) have been studied systematically in alcohol within visible spectra range in this paper. The results showed that the derivative spectra method have a higher sensitivity and resolution for studying on f-f transitions. Two kinds of the ternary complexes compositions have been determined as follows: Ln3+: β-diketone: DPG=1: 4: 1 and Ln3+: β-diketone: phen=1: 3:1. The covalency parameters of complexes were calculated from the red shifts of absorption peaks. It turned out that the covalent bond between Ln3+ ions and ligands existed. To compare the atomic number with the stabilities of the complexes, the evident 'double-peak effect' were observed.