Two isostructural lanthanide complexes were synthesized by solvent evaporation with 3-dimethylaminobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine as ligands. The general formula of the structure is a [Ln(3-N,N-DMBA)3(5,5′-DM-2,2′-bipy)]2·2(3-N,N-DMHBA), Ln = (Gd(1), Tb(2)), 3-N,N-DMBA = 3-Dimethylamino benzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethyl-2,2′ bipyridine. Both complexes exhibited dimeric structures based on X-ray diffraction analysis. At the same time, infrared spectroscopy and Raman spectroscopy were used to measure the spectra of the complex. A thermogravimetric infrared spectroscopy experiment was performed to investigate the thermal stability and decomposition mechanism of the complexes. Measurements of the low-temperature heat capacity of the complexes were obtained within the temperature range of 1.9 to 300 K. The thermodynamic function was calculated by heat capacity fitting. In addition, the fluorescence spectra of complex 2 were studied and the fluorescence lifetime values were determined, and the energy transfer mechanism of complex 2 was elucidated.

中文翻译：

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由3-二甲氨基苯甲酸和5,5'-二甲基-2,2'联吡啶配体合成的新型稀土配合物：晶体结构、热力学和荧光性质

以3-二甲氨基苯甲酸和5,5'-二甲基-2,2'-联吡啶为配体，通过溶剂蒸发合成了两种同构稀土配合物。结构通式为 [Ln(3-N,N-DMBA)3(5,5′-DM-2,2′-bipy)]2·2(3-N,N-DMHBA), Ln = (Gd(1), Tb(2)), 3-N,N-DMBA = 3-二甲氨基苯甲酸酯, 5,5'-DM-2,2'-联吡 = 5,5'-二甲基-2,2 ' 联吡啶。根据 X 射线衍射分析，两种复合物均表现出二聚体结构。同时利用红外光谱和拉曼光谱测量了配合物的光谱。通过热重红外光谱实验研究了配合物的热稳定性和分解机理。在1.9至300 K的温度范围内测量了配合物的低温热容。通过热容拟合计算了热力学函数。此外，还研究了配合物2的荧光光谱并测定了荧光寿命值，阐明了配合物2的能量传递机制。