稀土-碱金属离子-吡啶二羧酸配合物[HoNa_(3)(2,6-dipic)_(3)(H_(2)O)_(8)]·4H_(2)O的结构及性质

Structure and properties of rare earth-alkali metal ion-pyridine dicarboxylic acid complex[HoNa_(3)(2,6-dipic)_(3)(H_(2)O)8]·4H_(2)O

合成了具有空间三维孔道结构的稀土-碱金属离子-吡啶二羧酸异核配合物[HoNa_(3)(2,6-dipic)_(3)(H_(2)O)_(8)]·4H_(2)O(CCDC:2245294),通过单晶X-射线衍射、热重、磁性分析对该化合物进行了表征。单晶结果表明,该化合物为单斜晶系,空间群为P2_(1/c),a=9.6973(14)?,b=19.179(4)?,c=18.060(3)?,α=γ=90°,β=91.534(5)°。配合物[HoNa_(3)(2,6-dipic)_(3)(H_(2)O)_(8)]·4H_(2)O的配位单元由Na^(+)通过O原子桥连,形成二维网状结构,再由C—H…O形式的氢键将结构拓展为三维结构。配合物热分解过程大致分为两个阶段,有较好的热稳定性。通过变温磁化率可推断出配合物中稀土离子之间具有反铁磁相互作用,实际有效磁矩的计算表明配体对稀土离子Ho~Ⅲ的磁交换作用影响较小。

The rare earth-alkali metal ion heteronuclear complex based on pyridine dicarboxylic acid[HoNa_(3)(2,6-dipic)_(3)(H_(2)O)_(8)]·4H_(2)O(CCDC:2245294)with three-dimensional structure was successfully synthesized.The structure and properties of the com-plex were characterized by single-crystal X-ray diffraction,thermogravimetric analysis and magnetic characterization.The results of single-crystal X-ray diffraction show that the complex crystallizes in the monoclinic spacegroup P21/c with unit cell parameters a=9.6973(14)?,b=19.179(4)?,c=18.060(3)?,α=γ=90°,β=91.534(5)°.The coordination unit of the complex[HoNa3(2,6-dipic)_(3)(H_(2)O)_(8)]·4H_(2)O is connected by Na^(+)via O atom to form a two-dimensional network structure,and then expands the structure to three dimensional structure by C—H…O hydrogen bond.The thermal decomposition process of the complex is roughly divided into two stages,which indicates that the complex has great thermal stability.The antiferromagnetic interaction between rare earth ions in the complex can be inferred from the variable-temperature magnetic susceptibility,and the calculation of actual effec-tive magnetic moment shows that the ligand has little effect on magnetic exchange interaction from rare earth ion HoⅢ.