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在水热条件下,通过使用羧酸和螯合配体得到了一个系列的四核镧系簇合物,即[Ln4(mnba)12(tzp)2(H2O)2](Ln=Gd(1),Tb(2),Er(3);Hmnba=间硝基苯甲酸;tzp=2-(1H-1,2,4-三唑-3-基)吡啶))。这3个化合物是同构的,且具有线性的四核簇结构。磁性研究表明,化合物1和3中簇内镧系离子之间是弱铁磁耦合的,但化合物2中铽离子之间是弱的反铁磁相互作用和(或)铽离子激发的斯塔克能级的去布居。化合物1具有较大的磁热效应(-ΔSmmax=20.6 J·kg-1·K-1)。交流磁化率测试表明化合物3展现出频率和温度依赖的虚部信号,这是慢磁弛豫的典型特征,原因是铒离子的强各向异性和铁磁耦合的存在。
Under hydrothermal conditions, a series of tetranuclear lanthanide clusters, namely [Ln4 (mnba) 12 (tzp) 2 (H2O) 2] ), Tb (2), Er (3); Hmnba = m-nitrobenzoic acid; tzp = 2- (1H-1,2,4-triazol-3-yl) pyridine). These three compounds are isomorphic and have a linear tetranuclear cluster structure. Magnetic studies show that the lanthanide ions in clusters 1 and 3 are weakly ferromagnetically coupled to each other, but the terbium ions in compound 2 are weakly antiferromagnetic and / or terbium-excited The level to go to settle. Compound 1 has a larger magnetocaloric effect (-ΔSmmax = 20.6 J · kg -1 · K -1). AC susceptibility testing showed that compound 3 exhibited a frequency and temperature-dependent imaginary signal, which is a typical feature of slow magnetic relaxation due to the strong anisotropy of erbium ions and the presence of ferromagnetic coupling.