摘要
以硝酸铕、2-（4-氟代苯甲酰基）苯甲酸（HL）、1,10-菲咯啉（Phen）和三苯基氧膦（TPPO）合成了EuL3（H2O）6,EuL3Phen（H2O）4和EuL3（TPPO）（H2O）5三种固态配合物。用元素分析、红外光谱、核磁共振氢谱对配合物进行了组分确定和结构表征。IR表明,2-（4-氟代苯甲酰基）苯甲酸与Eu^3＋形成配合物后,位于1 692 cm^-1处羧基的νC O峰消失,2 500-3 200 cm^-1处羧基的νO—H峰也消失,出现了羧酸盐特有的反对称伸缩振动吸收峰（aνs（CO2^-））和对称伸缩振动吸收峰（sν（CO2-））,且Δν（aνs（CO2^-）-sν（CO2^-））与钠盐的Δν相近,说明羧酸根与Eu^3＋以对称双齿桥式配位。在1H NMR中,形成配合物后第一配体苯环上的质子峰变为宽峰且移向高场,Phen和TPPO中质子化学位移移向低场。室温下测定了配合物的荧光激发光谱和发射光谱,激发光谱表明配合物EuL3（H2O）6,EuL3Phen（H2O）4和EuL3（TPPO）（H2O）5的最佳激发波长分别为353.0,355.0和357.0 nm;发射光谱均显示Eu^3＋离子的特征发射光谱,且表明Phen对Eu3＋离子的荧光发射有明显增强作用。
The present paper reports three new europium complexes,EuL3（H2O）6,EuL3Phen（H2O）4 and EuL3（TPPO）（H2O）5,synthesized with Eu（NO3）3·6H2O,2-（4-fluorobenzoyl） benzoic acid,Phen and TPPO（L=2-（4-fluorobenzoyl） benzoic acid,Phen=1,10-phenanthroline,TPPO=triphenyl phosphine oxide）.Their composition and chemical structures were characterized by elemental analysis,IR and 1H NMR spectroscopy.The IR spectra indicated that all complexes exhibited the characteristic peaks of carboxylate,asymmetric stretching vibration（νas（CO-2）） and symmetric stretching vibration（νs（CO-2）） peaks;the CO stretching band at 1 692 cm-1 of COOH and the O—H stretching band around 2 500-3 200 cm^-1 disappeared.All these complexes had a smaller Δν（νas（CO-2）-νs（CO-2）） value than that of NaL,so the carboxylate groups coordinated with the europium ion in the form of bridging bidentate.In 1HNMR,the signals of hydrogen in 2-（4-fluorobenzoyl） benzoic acid became wide and shifted upfield,and those in Phen,TPPO shifted downfield.The excitation and emission spectra were recorded at room temperature.The excitation spectra showed that the optimum excitation peaks of these three complexes,EuL3（H2O）6,EuL3Phen（H2O）5 and EuL3（TPPO）（H2O）5,were at 353.0,355.0 and 357.0 nm,respectively.All these three complexes showed Eu3＋ ion characteristic emission bands,the electron-dipole transition ^5D0→^7F2 and magnetism dipole transition ^5D0→^7F,their emission peaks were at 596.0,617.0;596.0,619.0;595.0,620.0 nm,and the relative intensities were 1.1,8.,15.2,100.0;3.6,23.2,respectively.The intensity of 5D0→7F2 was stronger than that of ^5D0→^7F1,which indicated that europium ions were at asymmetric center.The emission intensities of europium ions were greatly sensitized by Phen.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2009年第1期156-160,共5页
Spectroscopy and Spectral Analysis
基金
国家自然科学基金项目(50403026)资助
