[Mn4IIILn4III] Calix[4]arene Clusters as Enhanced Magnetic Coolers and Molecular Magnets
[Mn4IIILn4III] Calix[4]arene Clusters as Enhanced Magnetic Coolers and Molecular Magnets
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DOI：
10.1021/ja104848m
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发表时间：
2010-09-22
影响因子：
15
通讯作者：
Brechin, Euan K.
中科院分区：
文献类型：
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作者：
Karotsis, Georgios;Kennedy, Stuart;Brechin, Euan K.
在3d/4f化学中使用亚甲基桥连的杯[4]芳烃产生通式[Mn（4）（III）Le（4）（III）（OH）（4）（C4）（4）（NO3）（2）（DMF）（6）（H2O）（6）]（OH）（2）的簇族（其中C4 =杯[4]芳烃; Ln = Gd（1），Tb（2），Dy（3））。分子结构描述了一个正方形的Ln（III）离子容纳在一个正方形的Mn-III离子。磁性研究表明，1具有大量的分子自旋状态，即使在最低的研究温度下也会被填充，而铁磁极限S = 22仅在最高的外加磁场下接近。这与高磁各向同性相结合，使复合物成为低温应用的优秀磁制冷剂。用各向异性的Tb-III和Dy-III离子替换各向同性的Gd-III离子“切换”了簇的磁性，使得2和3表现为低温分子磁体，显示出缓慢的磁化弛豫。
The use of methylene-bridged calix[4]arenes in 3d/4f chemistry produces a family of clusters of general formula [Mn(4)(III)Le(4)(III)(OH)(4)(C4)(4)(NO3)(2)(DMF)(6)(H2O)(6)](OH)(2) (where C4 = calix[4]arene; Ln = Gd (1), Tb (2), Dy (3)). The molecular structure describes a square of Ln(III) ions housed within a square of Mn-III ions. Magnetic studies reveal that 1 has a large number of molecular spin states that are populated even at the lowest investigated temperatures, while the ferromagnetic limit S = 22 is being approached only at the highest applied fields. This, combined with the high magnetic isotropy, makes the complex an excellent magnetic refrigerant for low-temperature applications. Replacement of the isotropic Gd-III ions with the anisotropic Tb-III and Dy-III ions "switches" the magnetic properties of the cluster so that 2 and 3 behave as low-temperature molecular magnets, displaying slow relaxation of the magnetization.