协同发光效应及机理探讨

在研究共存离子对稀土配合物荧光强度影响时发现,许多稀土和非稀土离子在一定浓度范围内可对配合物的荧光产生增强效应.这种现象与协同萃取类似,我们将其命名为“协同发光效应”.本文采用激光诱导荧光光谱法,研究了十四种稀土离子对Eu、Sm-TTA-Phen-Triton X-100体系和Eu、Sm-DBM-CPB体系的协同发光效应.并从稀土离子的化学性质,光谱能级和所形成配合物的化学结构和空间结构等方面综合考虑,提出协同发光机理.拟定出用于痕量铕和钐测定的薪的超高灵敏度分析方法.

STUDY ON SYNERGISTIC LUMINESCENCE EFFECT AND ITS LUMINESCENCE MECHANISM

A new sensitized fluorescence phenomenon was observed by adding some of metal ions to europium, samarium-dibenzoylmethane-cetylpyridium bromide(Eu, Sm-DBM-CPB)or europium, samarium-lhenoyltrifluoroacetone-1, 10-phenanthroline-Triton X-100 (Eu, Sm-TTA-Phen-TX-100) systems, which is named as a synergistic luminescence effect. The synergistic luminescence effect and its luminescent mechanism were studied using laser--induced fluorimetry.The influence of the chemical properties of rare earth ions on the synergistic luminescence effects of above systems is reported. In general, the synergistic luminescence effect is enhanced with the increase of ionic radius of synergistic ions. The systems exhibit similar fluorescence characteristics in the presence of different synergistic ions.From the experimental results, a mechanism of synergistic luminescence is proposed. The following factors affect the synergistic luminescence.1. Synergistic ions do not form new chelates with luminescent ion chelates. The solid solution is formed between luminescent ion chelates and synergistic ion chelates.2. Synergistic luminescence effect is influnced by the structure and symmetry of the chelates of luminescent ion and synergistic ion. 3. All the synergistic ions which have enhanced effect, except terbium, dysprosium and ytterbium, possess 8 stable outer electronic orbit. The synergistic luminescence effects of terbium,dysprosium and ytterbium ions can be explained by the valence fluctuation between the synergistic ions and ligands.The excitation energy transfer plays an important part in the energy transfer of synergistic luminescence effect.The proposed method can be used for determination of trace amounts of europium and samarium. Results are satisfactory for the determination of trace europium and samarium in highly pure rare earth oxides and synthetic samples without pre-separation.