Shi Xiao-Ming, Tang Rui-Ren, Gu Guo-Liang, Huang Ke-Long
School of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, PR China.
Spectrochim Acta A Mol Biomol Spectrosc. 2009 Feb;72(1):198-203. doi: 10.1016/j.saa.2008.09.019. Epub 2008 Oct 14.
A novel bis-pyrazolyl-carboxyl ligand, 2,6-bis(5-methyl-3-carboxypyrazol-1-ylmethyl)pyridine (L), was designed and synthesized and its several lanthanide(III) complexes Eu(III), Tb(III), Sm(III) and Gd(III) were successfully prepared and characterized in detail based on elemental analysis, infrared, mass, proton nuclear magnetic resonance spectroscopy and TG-DTA studies. Analysis of the IR spectra suggested that each of the lanthanide metal ions coordinated to the ligand via the carbonyl oxygen atoms and the nitrogen atom of the pyridine ring and pyrazole rings. The fluorescence spectra exhibits that the Tb(III) complex and the Eu(III) complex display characteristic metal-centered fluorescence in solid state while ligand fluorescence is completely quenched. However, the Tb(III) complex displays more effective fluorescence than the other complexes, which is attributed to especial effectivity in transferring energy from the lowest triplet energy level of the ligand (L) onto the excited state ((5)D(4)) of Tb(III).
设计并合成了一种新型双吡唑基羧基配体2,6-双(5-甲基-3-羧基吡唑-1-基甲基)吡啶(L)，并成功制备了其几种镧系(III)配合物Eu(III)、Tb(III)、Sm(III)和Gd(III)，基于元素分析、红外光谱、质谱、质子核磁共振光谱和TG-DTA研究对其进行了详细表征。红外光谱分析表明，每个镧系金属离子通过羰基氧原子以及吡啶环和吡唑环的氮原子与配体配位。荧光光谱表明，Tb(III)配合物和Eu(III)配合物在固态下呈现特征性的以金属为中心的荧光，而配体荧光完全猝灭。然而，Tb(III)配合物比其他配合物表现出更有效的荧光，这归因于从配体(L)的最低三重态能级到Tb(III)的激发态((5)D(4))的能量转移具有特殊的有效性。
