A cyanido-bridged trinuclear {FeIII2NiII} complex decorated with organic radicals
A cyanido-bridged trinuclear {FeIII2NiII} complex decorated with organic radicals
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DOI：
10.1016/j.poly.2013.04.039
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发表时间：
2013-08
期刊：
影响因子：
2.6
通讯作者：
Yuan-Zhu Zhang;Dong-feng Li;R. Clérac;S. Holmes
中科院分区：
文献类型：
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作者：
Yuan-Zhu Zhang;Dong-feng Li;R. Clérac;S. Holmes
[NEt 4][（pzTp）FeIII（CN）3]、三氟甲磺酸镍（II）与4，4，5，5-四甲基咪唑啉-1-氧基-2-（2′-吡啶基）（IM-2 Py）反应，得到了一个氰基桥联的三核配合物{[（pzTp）FeIII（CN）3]2NiII（IM-2 Py）2}·2DMF·H2O·0.5Et2O（1）。根据磁性数据的模拟判断，{FeIII 2NiII}（S=2）和两个IM-2 Py（S= 1/2）自由基配体之间的磁性交换可以忽略不计，或者换句话说，每个自由基对配合物的整体顺磁性都有居里贡献;最佳参数集为giso=2.53（5），格拉德=2（固定），Jiso/kB=3.9（1）K。交流磁化率和M对H的数据表明，1在1.8K以上没有表现出缓慢的磁化弛豫。与磁性数据相一致，我们得出结论，弯曲的氰化物桥，FeIIILSanisotropy张量的不正确对齐，和/或小IM-2 Py环扭曲合谋带来不足的磁各向异性的复杂，并防止观察单分子磁体行为。
Reaction of [NEt4][(pzTp)FeIII(CN)3], nickel(II) trifluoromethanesulfonate and 4,4,5,5-tetramethylimidazoline-1-oxyl-2-(2′-pyridyl) (IM-2Py) affords {[(pzTp)FeIII(CN)3]2NiII(IM-2Py)2}·2DMF·H2O·0.5Et2O (1) as a bent cyanide-bridged trinuclear complex. As judged from simulations of the magnetic data, the magnetic exchange between the {FeIII2NiII} (S=2) and both IM-2Py (S=½) radical ligands are negligible, or in other words, each radical imparts a Curie contribution to the overall paramagnetism of the complex; the best set of parameters are giso=2.53(5), grad=2 (fixed), and Jiso/kB=3.9(1) K. ac susceptibility and M versus H data show that 1 does not exhibit slow relaxation of the magnetization above 1.8K. Consistent with the magnetic data, we conclude that bent cyanide bridges, an improper alignment of the FeIIILSanisotropy tensors, and/or small IM-2Py ring distortions conspire to bring insufficient magnetic anisotropy to the complex, and prevent observation of single-molecule magnet behavior.