4,4’-联吡啶桥联的链状Zn(Ⅱ)配合物:合成、晶体结构和对Tb(Ⅲ)离子的荧光敏化

4,4'-Bipyridine Bridged Chain Zn(Ⅱ) Complex:Synthesis,Crystal Structure and Fluorescence Sensitization for Tb(Ⅲ) Ion

以硝酸锌与3,4’-联苯二甲酸(3,4’-H2dpdc),4,4’-联吡啶(4,4’-bpy)为反应物,以水为溶剂,适当调节pH值,通过水热反应,得到配合物[Zn(3,4’-Hdpdc)_2(4,4’-bpy)](Zn-MOF)。利用X射线单晶衍射测试分析确定了该配合物是由4,4’-bpy配体桥联Zn(Ⅱ)离子形成的"Z"形链结构,属于单斜晶系,C2/c空间群。在278nm激发下,Zn-MOF的荧光发射光谱在341~537nm范围出现宽发射峰,最强发射峰波长406nm,属于配体的π*—π跃迁。研究了该配合物对Tb(Ⅲ)离子发光性能的影响。实验结果表明,Zn-MOF可敏化甲醇和水溶液中的Tb(Ⅲ)离子,使Tb(Ⅲ)离子的特征荧光发射峰增强。在荧光光谱490,545,585和624nm出现强的线状发射峰,对应于Tb(Ⅲ)离子的~5D_4→~7F_J(J=6~3)跃迁。最强发射峰位于545nm(~5D_4→~7F_5),为绿光。Zn-MOF可用作荧光探针检测甲醇和水溶液中的Tb(Ⅲ)离子。

A metal-organic framework[Zn（3,4＇-Hdpdc）2（4,4＇-bpy）]（Zn-MOF）has been synthesized by hydrothermal reaction with the Zn（NO3）2·6H2O,3,4＇-biphenyl dicarboxylic acid（3,4＇-H2dpdc）and 4,4＇-bipyridine（4,4＇-bpy）,and its crystal structure was confirmed by X-ray single crystal diffraction.The complex was the monoclinic system,C2/c space group.The complex had a＂Z＂-shaped chain structure formed by the 4,4＇-bpy ligand and Zn（Ⅱ）ion.The Zn-MOF exhibited intense ligandbased blue luminescence with the maximum excitation wavelength of 278 nm,and the emission band was in the range of 341～537 nm from theπ＊—πtransition of the ligand.The emission maximum was at 406 nm.The luminescence properties of the complex toward Ln（Ⅲ）metal ions in methanol/aqueous solutions were studied.Fluorescence spectrum show the characteristic emission peaked of Tb（Ⅲ）ions at 490,545,585 and 624 nm,which corresponded to ^5D4→^7FJ（J=6～3）transitions of Tb（Ⅲ）,the strongest emission peaked at 545 nm（^5D4→^7F5）,for the green light.The experimental results showed that the ZnMOF can sensitize the Tb（Ⅲ）ion in the methanol solution and in water,and thus the compound can be used as a fluorescent probe to detect Tb（Ⅲ）ions in methanol solutions and in water.