Two Locally Chiral Dysprosium Compounds with Salen‐Type Ligands That Show Slow Magnetic Relaxation Behavior
Two Locally Chiral Dysprosium Compounds with Salen‐Type Ligands That Show Slow Magnetic Relaxation Behavior
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DOI：
10.1002/ejic.201201336
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发表时间：
2013-03
影响因子：
2.3
通讯作者：
Li Zhang;Peng Zhang;Lang Zhao;Shuang-Yan Lin;Shufang Xue;Jinkui Tang;Zhiliang Liu
中科院分区：
文献类型：
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作者：
Li Zhang;Peng Zhang;Lang Zhao;Shuang-Yan Lin;Shufang Xue;Jinkui Tang;Zhiliang Liu
通过salen型配体N， N′-双（3-甲氧基水杨酸基）-1,2-环己二胺（H2L）与不同的镝盐和碱的反应，合成了两个Dy化合物[Dy-4(mu(4)-O)L-2(C6H5COO)(6)]中心点3CH(3)OH(1)和[Dy2L(H2L)(teaH(2))（o-香兰素）（H2O）](ClO4)(2)中心点2CH(3)OH中心点H2O （2, teaH(3) =三乙醇胺）。这些化合物具有局部手性和慢磁弛豫。前者是由一种前所未有的配体H2L的配位模式引起的，其中N2O2口袋封装了一个Dy离子。化合物1在不同的配位环境中含有4个Dy离子，单晶x射线分析显示，化合物1具有罕见的由中心mu(4)-O原子支撑的Dy-4四面体基序，类似于有机分子中的手性碳原子。相反，2的形成是由三乙醇胺的存在驱动的，它显示了一个不寻常的带有尾巴的结构基序。尽管每个Dy离子周围的低对称配位几何结构，但两种化合物都表现出缓慢的磁弛豫行为，但具有快速的量子隧道弛豫，正如交流（ac）磁化率测量所表明的那样。
Two Dy compounds, [Dy-4(mu(4)-O)L-2(C6H5COO)(6)]center dot 3CH(3)OH (1) and [Dy2L(H2L)(teaH(2))(o-vanillin)(H2O)](ClO4)(2)center dot 2CH(3)OH center dot H2O (2, teaH(3) = triethanolamine), were assembled by the reactions of the salen-type ligand N, N'-bis(3-methoxysalicylidene)-1,2-cyclohexanediamine (H2L) and different dysprosium salts and bases. These compounds show both local chirality and slow magnetic relaxation. The former is induced by an unprecedented coordination mode of the ligand H2L, in which the N2O2 pocket encapsulates one Dy ion. Compound 1, which has four Dy ions in distinct coordination environments, demonstrates the rare Dy-4 tetrahedron motif supported by a central mu(4)-O atom, which is akin to a chiral carbon atom in organic molecules, as revealed by single-crystal X-ray analyses. In contrast, the formation of 2, which shows an unusual structural motif with a tail, is driven by the presence of triethanolamine. In spite of the low-symmetry coordination geometry around each Dy ion, both compounds display slow magnetic relaxation behavior, but with fast quantum tunneling relaxation, as indicated by alternating current (ac) susceptibility measurements.