对苯二甲酸双核稀土冠醚配合物的合成、表征及荧光性能的研究

Synthesis, Characterization and Luminescence of Dinuclear Rare Earth Complexes with Crown Ether and p-Phthalic Acid

在乙腈介质中,除水剂原甲酸三乙酯存在下,合成了以Eu(Ⅲ),Eu(Ⅲ) La(Ⅲ),Eu(Ⅲ) Gd(Ⅲ)为中心,以冠醚(18 C 6)及对苯二甲酸为配体的同核铕及其铕 镧、铕 钆异核稀土配合物,并对其进行了元素分析、红外光谱分析及荧光性能的测定和研究。发现空腔较大的18 C 6不仅可以与半径大的La3+离子配位,还可以与半径小的Eu3+和Gd3+离子配位。非荧光的La(Ⅲ),Gd(Ⅲ)对Eu(Ⅲ)的发光有较强的敏化作用,桥联配体对苯二甲酸根可有效地传送能量。与大多数铕配合物不同,所研究的配合物的5D0→7F0跃迁强度非常高。

The same and different binuclear rare earth complexes of Eu(Ⅲ)-Eu(Ⅲ), Eu(Ⅲ)-La(Ⅲ) and Eu(Ⅲ)-Gd(Ⅲ) with crown ether (18C6) and p-phthalic acid were synthesized in acetonitrile. The compositions are found to be Eu_2L_2L′(ClO_4)_4·6H_2O, EuLaL_2L′(ClO_4)_4·6H_2O and EuGdL_2L′(ClO_4)_4·6H_2O (L=18C6, L′=p-phthalate), respectively. The IR absorption spectra and fluorescence spectra were studied. The results show that not only the crown ether with diameter 260～320 pm can coordinate to La^(3+) ion which radius is bigger, but also can coordinate to Eu^(3+) and Gd^(3+) ions whose radii are smaller. The emission intensity of Eu^(3+) ion is greatly enhanced by La^(3+) and Gd^(3+) ions in the complexes. p-phthalate transfers the absorbing energy of lanthanum and gadolinium complexes in a more effective way. There is a difference from ordinary europium complexes in which the fluorescence emission intensity of (()~5D_0)-(()~7F_0) is very weak, but it is stronger in the title complexes.