惰性稀土离子和抗衡离子对2-噻吩乙醛酸-铕配合物荧光性能的影响

研究了惰性稀土离子和抗衡离子对一系列2-噻吩乙醛酸-铕配合物荧光性能的影响。分别在2-噻吩乙醛酸-邻菲罗啉-铕和2-噻吩乙醛酸-三苯基氧化膦-铕两个体系中按不同比例掺入钇和钆,研究了它们的荧光光谱。结果表明,钇的加入对2-噻吩乙醛酸-邻菲罗啉-铕体系的荧光强度有很强的敏化作用,并且随加入量的增加,这种敏化作用逐渐增强。钇的加入对2-噻吩乙醛酸-三苯基氧化膦-铕体系则呈现出弱的敏化作用,且在一定程度上具有猝灭作用,但这两种作用都是很微小的。钆在少量加入时对2-噻吩乙醛酸-三苯基氧化膦-铕体系具有猝灭作用,当大量加入时则呈现出很强的敏化作用。不同的抗衡离子对配合物的影响是明显的。在二元配合物中,氯化物体系的固体荧光强度最大;在三元配合物中,硝酸盐体系的固体荧光强度最大。

Influence of Inert Lanthanide Ions and Counter Ions on the Luminescence Properties of Europium Complexes with 2-Thiopheneglyoxylic Acid

In recent years,there has been considerable interest in the study on the luminescence enhancement effects of the rare earth complexes.An effective approach to increase the luminescent efficiency is to modify the complexes with different kinds of counter ions,such as Cl^-,NO^-₃,ClO^-₄.Another way is to mix certain anion rare earth ions,such as La³⁺,Gd³⁺,and Y³⁺,could significantly enhance the luminescence intensities of the complexes of Eu³⁺,Tb³⁺,and Sm³⁺.In order to study the luminescence enhancement effects of anion ions,a series of europium complexes of 2-thiopheneglyoxylic acid(HL),o-phenathroline(phen) and triphenyl phosphine oxide(TPPO) with different molar ratios of Eu³⁺ to Y³⁺ and Gd³⁺ have been synthesized.The luminescence spectra were taken on WGY-10 fluorescence spectrophotometer.Enhancement of Eu³⁺ fluorescence in Eu-L-phen complex system has been observed by addition of Y³⁺ and reach maximum when the molar ratio of Eu³⁺:Y³⁺ is 0.7:0.3.Then the(luminescence) intensity of the complexes decreases with a further increase of the Y³⁺ content.Concluded from R=I_t/I_p(I_t=theoretical values of the fluorescence emission intensity,I_p=practical values) is all above(1.0).When Y³⁺ ions added to Eu-L-TPPO complex system,weak sensitization even extinguishment to some extent could be observed.In this system,R values of each complex approach 1.0.When a little amount of Gd³⁺ ions added to Eu-L-TPPO complex system,it can extinguish the fluorescence intensity.R values are(below) 1.0 when molar ratio of Eu³⁺: Gd³⁺ is 1:0⁶:4,only the R value for peaks at 699 nm is 1.3 when molar ratio of Eu³⁺:Gd³⁺ is 6:4.But adding a large amount of Gd³⁺ ions can sensitize obviously.This kind of luminescence enhancement due to the energy transfer process between ligands and lanthanum ions.The luminescence enhancement effects of counter ions(NO^-₃,Cl^-,ClO^-₄) were also studied.In binary complexes,the fluorescence intensity of chloride system is the largest of all,and that of nitrate system the(largest) in ternary complexes.Luminescence properties of lanthanide ions could be great influenced by the(geometry) of their complexes,respectively.