两种溴代苯甲酸-铽配合物的合成、晶体结构与性质表征

溶液法合成了2种配合物Tb(2-BrBA)₂(CH₃COO)(2，2′-bipy)]₂ (1)和Tb(3-BrBA)₃(2，2′-bipy)]₂·2(3-HBrBA)·2H₂O (2)(2-BrBA=2-bromobenzoate，3-BrBA=3-bromobenzoate，2，2′-bipy=2，2′-bipyridine)，并用X-射线单晶衍射方法测定了其晶体结构。配合物1和2均属于三斜晶系和P1空间群。四元混配配合物1是具有反演中心的二聚体，其中Tb³⁺离子同时与2种不同的羧酸配体配位。4个2-BrBA以双齿桥联的方式把2个Tb³⁺离子联结起来，而乙酸根和2，2′-bipy分子则分别以双齿螯合的方式与Tb³⁺离子配位。配合物2是三元混配配合物，2个Tb³⁺离子通过4个双齿桥联的3-BrBA联结而成具有反演中心的二聚体，每个Tb³⁺离子还同时与1个双齿螯合的3-BrBA和1个2，2′-bipy分子配位。配合物1和2在紫外灯照射下能发出强烈的绿光，而且在它们的荧光光谱中都存在4条谱线：489、545、585和621 nm，分别对应于Tb³⁺离子的 ⁵D₄ → ⁷F₆、 ⁵D₄ → ⁷F₅、 ⁵D₄→ ⁷F₄和 ⁵D₄→ ⁷F₃跃迁。

Synthesis, Crystal Structure and Characterization of Two Terbium Complexes with Bromobenzoic Acid

Two complexes of Tb(2-BrBA)2(CH3COO)(2,2'-bipy)]2 (1) and Tb(3-BrBA)3(2,2'-bipy)]2·2(3-HBrBA)·2H2O (2) (2-BrBA=2-bromobenzoate, 3-BrBA=3-bromobenzoate, 2,2'-bipy=2,2'-bipyridine) were synthesized by solvent method and their structures were determined by X-ray single crystal diffraction method. Complexes 1 and 2 both belong to triclinic system and P(-1) space group. The complex 1 is a dimer with an inversion center, in which two different carboxylate ligands coordinate to Tb3+ ion simultaneously to form quaternary mixed-ligands complex. Four 2-BrBA ligands link the two Tb3+ ions by bidentate-bridging mode, two acetate ligands coordinate to two Tb3+ ions by bidentate-chelating mode, and two 2,2'-bipy molecules chelate to two Tb3+ ion, respectively.The ternary complex 2 is also a dimer with an inversion center, in which the two Tb3+ ions are linked by four bidentate-bridging 3-BrBA ligands and each Tb3+ ion is further bonded to one bidentate-chelating 3-BrBA ligand and one 2,2'-bipy molecule. The two complexes exhibit strong green fluorescence under ultraviolet light and the fluorescence spectrums of them both have four peaks at 489, 545, 585 and 621 nm corresponding to 5D4 → 7F6,5D4 → 7F5, 5D4→ 7F4 and 5D4→ 7F3 transition emissions of the Tb3+ ion, respectively. CCDC: 631975, 1; 631976, 2.