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Updated: Sep 25, 2025
Preparation, Purification, and Characterization of Lanthanide Complexes for Use as Contrast Agents for Magnetic Resonance Imaging
Published on: July 21, 2011
Lanthanide complexes based on a conjugated pyridine carboxylate ligand: structures, luminescence and magnetic
Rong-Fang Li1, Rui-Hao Li1, Xin-Fang Liu1
1College of Chemistry and Chemical Engineering, Henan Key Laboratory of Function Oriented Porous Materials, Luoyang Normal University Luoyang Henan 471934 China fengx@lynu.edu.cn.
Abstract:
Three lanthanide compounds have been synthesized, namely, {[Dy2(bpda)3(H2O)3]4·2H2O}(Dy-1), {[Sm(bpda)2·(H2O)]·H2O} (Sm-2) and {[Tb2(bpda)3(H2O)3]4·2H2O} (Tb-3) (H2bpda = 2,2'-bipyridine-6,6'-dicarboxylic acid). Their structures were determined by single crystal X-ray diffraction and characterized by elemental analysis, infrared spectroscopy and thermogravimetric analysis. Dy-1 and Tb-3 are isostructural with a conjugate bimolecular four-nuclear cluster structure constructed with intramolecular hydrogen bonds and they form a 3D supramolecular structure with intermolecular hydrogen bonding. Sm-2 is a one-dimensional chain structure and is further connected by intricate hydrogen bonds into a three-dimensional supramolecular structure. These three compounds exhibit significant characteristic luminescence from the ligand to the central Ln(iii) ion, which is found by solid-state photoluminescence measurement. Sm-2 exhibits a long luminescence lifetime and high fluorescence quantum yield. A slow relaxation phenomenon is observed for the dysprosium compound by measuring the alternating-current susceptibility at low temperature and the underlying mechanism was further confirmed by theoretical calculations.
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