Structures, luminescent and magnetic properties of six lanthanide–organic frameworks: observation of slow magnetic relaxation behavior in the DyIII compound
作者:Yin-Ling Hou、Gang Xiong、Bo Shen、Bin Zhao、Zhi Chen、Jian-Zhong Cui
DOI:10.1039/c2dt32390g
日期:——
Six novel three-dimensional (3D) lanthanide metalâorganic frameworks (LnMOFs), [Ln2(ispc)3(H2O)3]·mH2O}n (Ln = Pr (1, m = 5); Eu (2, m = 5); Gd (3, m = 4); Tb (4, m = 5); Dy (5, m = 5) and Ho (6, m = 4)), ispc = 3-(4-carboxyphenylsulfonyloxy)-4-methoxybenzoic anion) have been synthesized under hydrothermal conditions. Single crystal X-ray diffraction revealed they are isostructural and crystallize in the triclinic crystal system, space group P. The investigations on luminescent properties and lifetimes of 2 (EuIII), 4 (TbIII), and 5 (DyIII) exhibit characteristic emissions of EuIII, TbIII and DyIII ions and the corresponding luminescent lifetimes are 0.14 ms, 9.93 μs and 1.25 ms, respectively. The different luminescent intensities and lifetimes among them were further discussed. Furthermore, magnetic studies of 1â6 reveal that 3â6 exhibit ferromagnetic coupling, and 5 (DyIII) exhibits remarkably slow magnetic relaxation behavior with the energy barrier ÎE/kB = 49.2 K.
合成了六种新型三维(3D)镧系金属有机框架(LnMOFs),[Ln2(ispc)3(H2O)3]·mH2O}n(Ln = Pr (1, m = 5); Eu (2, m = 5); Gd (3, m = 4); Tb (4, m = 5); Dy (5, m = 5) 和 Ho (6, m = 4)),其中ispc = 3-(4-羧基苯磺酰氧)-4-甲氧基苯酸离子),是在水热条件下合成的。单晶X射线衍射显示它们具有同构结构,结晶于三斜晶系,空间群P。对2(EuIII)、4(TbIII)和5(DyIII)的荧光性质和寿命的研究显示了EuIII、TbIII和DyIII离子的特征发射,相应的荧光寿命分别为0.14毫秒、9.93微秒和1.25毫秒。对它们之间不同的荧光强度和寿命进行了进一步讨论。此外,1-6的磁性研究表明,3-6表现出 ferro 磁耦合,而5(DyIII)则显示出显著缓慢的磁弛豫行为,能量屏障为ΔE/kB = 49.2 K。