Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, D-76131, Karlsruhe, Germany.
Dalton Trans. 2010 May 28;39(20):4911-7. doi: 10.1039/c002841j. Epub 2010 Apr 17.
The reaction of 2,6-pyridinedimethanol (pdmH(2)), CoCl(2)·6H(2)O, Ln(NO(3))(3)·6H(2)O and pivalic acid (pivH) in the presence of triethylamine in MeCN and CH(2)Cl(2) under ambient conditions results in the tetranuclear heterobimetallic compounds [Co(II)(2)Ln(2)(pdmH)(4)(Piv)(6)]·4CH(3)CN (Ln = Y (1), Gd (2), Tb (3), Ho (4)) and [Co(II)(2)Dy(2)(pdmH)(4)(Piv)(6)]·2CH(3)CN (5). The molecular structures of 1-5 were determined by single-crystal X-ray diffraction and reveal that they are isostructural. However, compounds 1-4 crystallize in the monoclinic space group P2(1)/n, while compound 5 crystallizes in the orthorhombic space group Pnna. In all of these compounds, the four metal ions are held together by four alkoxide mu(3)-RCH(2)O(-) bridges to form novel Co(2)Ln(2)O(4)-heterocubanes. Magnetic properties of 1-5 have been investigated using dc and ac susceptibility measurements. Of these compounds, only compound 5 displays an out-of-phase signal in the ac susceptibility and exhibits slow relaxation of the magnetization, which is attributed to the presence of the anisotropic Dy(III) ions.
2,6- 吡啶二甲醇（pdmH(2)）、CoCl(2)·6H(2)O、Ln(NO(3))(3)·6H(2)O 和 2,2,6,6- 四甲基哌啶氧化物（TEMPO）在 MeCN 和 CH(2)Cl(2)中的反应，在室温条件下，在三乙胺的存在下，得到了四核异金属配合物[Co(II)(2)Ln(2)(pdmH)(4)(Piv)(6)]·4CH(3)CN（Ln = Y（1）、Gd（2）、Tb（3）、Ho（4））和[Co(II)(2)Dy(2)(pdmH)(4)(Piv)(6)]·2CH(3)CN（5）。通过单晶 X 射线衍射确定了 1-5 的分子结构，它们是同构的。然而，化合物 1-4 结晶在单斜空间群 P2(1)/n 中，而化合物 5 结晶在正交空间群 Pnna 中。在所有这些化合物中，四个金属离子通过四个烷氧基 mu(3)-RCH(2)O(-)桥连接在一起，形成了新颖的 Co(2)Ln(2)O(4)- 异核立方烷。使用直流和交流磁化率测量研究了 1-5 的磁性能。在这些化合物中，只有化合物 5 在交流磁化率中显示出反相信号，并表现出磁化的缓慢弛豫，这归因于各向异性 Dy(III)离子的存在。
