掺钙、钡苯甲酸铕配合物的红外光谱和荧光性能

Infrared Spectra and Fluorescence Property of Calcium,Barium and Europium-Benzoate Complexes

将苯甲酸钠分别加入到氯化钙和氯化铕以及氯化钡和氯化铕混合溶液中反应,制备了苯甲酸铕-钙和苯甲酸铕-钡两个系列的三元固体配合物,其化学组成式为 (Eu1-xCax)L3-x和(Eu1-xBax)L3-x(其中L为苯甲酸根,x=0～1.0),研究了它们的红外光谱和荧光性能.由红外数据表明,配合物中对称和反对称伸缩振动吸收峰发生了分裂,而且羧基伸缩振动随钙离子(钡离子)含量的增加发生规律性变化.荧光光谱实验结果表明,在一定范围内,用不发光的钙离子或者钡离子取代苯甲酸铕中部分Eu3+离子,可以使Eu3+离子的特征荧光发射增强,表明碱土金属可以敏化Eu离子.

The studies on the luminescence property of complexes of rare earth benzoate are attracting people＇s more interest increasingly. The luminescence of both complexes of Eu-Tb benzoate and complexes of Eu-La benzoate have been reported already; a high efficient Tb-Gd benzoate luminescence material was obtained by replacing a part of Tb^3＋ with Gd^3＋ ; also fluorescence intensity can be enhanced by replacing a proportion of Eu^3＋ with La^3＋ But interrelated report about Ca^2＋ and Ba^2＋ alkaline earth ions effecting fluorescence intensity of Eu^3＋ was not seen yet. So group members decided to complete this work by choosing facile alkaline earth metal and it has significant value if corking effect was gotten. Aim at this, a series of complexes of benzoic acid with europium-calcium and europium-barium were synthesized by the reaction of europium chloride and calcium chloride （or barium chloride） with sodium benzoate in aqueous solution. Their composition is expressed with the general formula （ Eu1-xCax ） L3-x and （ Eu1-xBax ） L3-x, where L = C6H5COO^- ,x = 0 - 1. 0）. Their infrared and fluorescence spectra were investigated. The characteristic asymmetric （Vas） vibrations of earboxyl group for EuL3, （ Eu1-xCax ） L3-x and （ Eu1-x Bax ） L3-x （x 〈 0.7 ） shift to lower frequency and the other complexes shift to higher frequency; in comparison with symmetric （Vs） shift to lower frequency for EuL3 and the other complexes shift to higher frequency. What is more, both the absorption bands （Vas and Vs ） show splitting. From above analysis, we could draw a conclusion that the coordinating pattern of the earboxyl groups in the complexes is the form of chelating-bidentate and the tridentate chelating-bridging. The dependence of the relative fluorescence intensity of the complexes upon the content for Ca^2＋ ion and Ba^2＋ ion was discussed. The results showed that the emission intensity for Eu^3＋ ions can be greatly enhanced if a part of Eu^3＋ ion in europium benzoate was substituted by Ca^2＋ ion or Ba^2 ＋ ion. When x = 0.1, the fluorescence intensity of the complexes is the highest. So it can be saying that not only the reserves abundant and inexpensive alkaline earth metallic ions were adulterated into complexes but higher fluorescence intensity than pure europium-benzoate complexes was achieved. These research results are very successful and will have wider application foreground.