State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Inorg Chem. 2012 May 21;51(10):5693-8. doi: 10.1021/ic300126q. Epub 2012 May 7.
Dy(III)(HBpz(3))(2) moieties (HBpz(3)(-) = hydrotris(pyrazolyl)borate) and a 3d transition-metal ion (Fe(III) or Co(III)) have been rationally assembled using an dithiooxalato dianion ligand into 3d-4f [MDy(3)(HBpz(3))(6)(dto)(3)]·4CH(3)CN·2CH(2)Cl(2) (M = Fe (1), Co (2) complexes. Single-crystal X-ray studies reveal that three eight-coordinated Dy(III) centers in a square antiprismatic coordination environment are connecting to a central octahedral trivalent Fe or Co ion forming a propeller-type complex. The dynamics of the magnetization in the two isostructural compounds, modulated by the nature of the central M(III) metal ion, are remarkably different despite their analogous direct current (dc) magnetic properties. The slow relaxation of the magnetization observed for 2 mainly originates from isolated Dy ions, since a diamagnetic Co(III) metal ion links the magnetic Dy(III) ions. In the case of 1, the magnetic interaction between S = 1/2 Fe(III) ion and the three Dy(III) magnetic centers, although weak, generates a complex energy spectrum of magnetic states with low-lying excited states that induce a smaller energy gap than for 2 and thus a faster relaxation of the magnetization.
Dy(III)(HBpz(3))(2) 配合物（HBpz(3)(-) = 六氢三（吡唑基）硼酸盐）和 3d 过渡金属离子（Fe(III) 或 Co(III)) 已使用二硫代氧代二乙酸根阴离子配体合理组装成 3d-4f [MDy(3)(HBpz(3))(6)(dto)(3)]·4CH(3)CN·2CH(2)Cl(2)（M = Fe（1），Co（2）复合物。单晶 X 射线研究表明，三个处于正方形反棱柱配位环境的八配位 Dy(III) 中心与中心八配位三价 Fe 或 Co 离子连接，形成螺旋桨型配合物。尽管具有类似的直流（dc）磁性质，但两种同构化合物的磁化动力学因中心 M(III) 金属离子的性质而显著不同。2 中观察到的磁化缓慢弛豫主要源于孤立的 Dy 离子，因为反磁性 Co(III) 金属离子连接了磁性 Dy(III) 离子。在 1 的情况下，S = 1/2 Fe(III) 离子与三个 Dy(III) 磁性中心之间的磁相互作用虽然较弱，但产生了具有低能激发态的复杂磁态能谱，这导致能量间隙比 2 小，从而使磁化弛豫更快。
