稀土配合物掺杂二氧化硅凝胶的原位光声光谱研究

Photoacoustic Spectral Study of the Formation of Lanthanide Complexes in Silica Gels

采用溶胶-凝胶法,制备了Ln(Bipy)2Cl3.2H2O(Ln3+:Eu3+,Er3+;Bipy:2,2′-联吡啶)配合物掺杂的二氧化硅凝胶样品。首次采用光声光谱分析了配合物在凝胶中的形成。对于仅经室温陈化、干燥的两种配合物掺杂的湿凝胶样品,在配体吸收处光声强度相同;而经120℃热处理后的凝胶样品在配体吸收处的光声强度有明显差别。结合荧光和红外光谱的结果表明,未经适当的热处理过程,凝胶样品中稀土配合物尚不能形成。进一步据光声谱计算了凝胶样品中铒离子的电子云重叠参数和光声支量值,分析了稀土离子的配位环境和成键性质变化。

Via a sol- gel process,lanthanide complexes Ln（Bipy）2Cl3·2H2O （Ln^3＋ ： Eu^3＋ ,Er^3＋ ; Bipy： 2,2＇ -bipyridyl） are incorporated into silica gels. Their photoacoustie （PA） spectra have been detected and imerpreted. For lanthanide complexes doped gel samples, which undergo aging and drying at room temperature, PA intensities in the region of the ligand absorption are nearly the same. Upon heat treatment at 120℃, PA intensities of the ligand change remarkably for the gel samples. The results indicate that lan- thanide complexes decompose in wet gels. By comparison with their fluorescence spectra, the formation of tanthanide complexes in silica gels is discussed from two aspects： radiative and non- radiative processes.