Escobar Lívia B L, Guedes Guilherme P, Soriano Stéphane, Speziali Nivaldo L, Jordão Alessandro K, Cunha Anna Claudia, Ferreira Vitor F, Maxim Catalin, Novak Miguel A, Andruh Marius, Vaz Maria G F
Instituto de Química and ‡Instituto de Física, Universidade Federal Fluminense , Niterói, Rio de Janeiro, Brazil.
Inorg Chem. 2014 Jul 21;53(14):7508-17. doi: 10.1021/ic5008044. Epub 2014 Jun 25.
In this work we report the synthesis, crystal structures, and magnetic behavior of 2p-3d-4f heterospin systems containing the nitroxide radical 4-azido-2,2,6,6-tetramethylpiperidine-1-oxyl radical (N3tempo). These compounds were synthesized through a one-pot reaction by using [Cu(hfac)2], [Ln(hfac)3] (hfac = hexafluoroacetylacetonate, Ln = Dy(III), Tb(III) or Gd(III)), and the N3tempo radical. Depending on the stoichiometric ratio used, the synthesis leads to penta- or trimetallic compounds, with molecular formulas [Cu3Ln2(hfac)8(OH)4(N3tempo)] (Ln = Gd, Tb, Dy) and [CuLn2(hfac)8(N3tempo)2(H2O)2] (Ln = Gd, Dy). The magnetic properties of all compounds were investigated by direct current (dc) and alternating current (ac) measurements. The ac magnetic susceptibility measurements of Tb(III)- and Dy(III)-containing compounds of both families revealed slow relaxation of the magnetization, with magnetic quantum tunneling in zero field.
在本工作中，我们报道了含氮氧自由基4-叠氮基-2,2,6,6-四甲基哌啶-1-氧基自由基（N3tempo）的2p-3d-4f异自旋体系的合成、晶体结构及磁行为。这些化合物通过一锅法反应合成，使用了[Cu(hfac)2]、[Ln(hfac)3]（hfac = 六氟乙酰丙酮，Ln = Dy(III)、Tb(III)或Gd(III)）以及N3tempo自由基。根据所使用的化学计量比，合成得到五金属或三金属化合物，其分子式分别为[Cu3Ln2(hfac)8(OH)4(N3tempo)]（Ln = Gd、Tb、Dy）和[CuLn2(hfac)8(N3tempo)2(H2O)2]（Ln = Gd、Dy）。通过直流（dc）和交流（ac）测量研究了所有化合物的磁性质。对这两个系列含Tb(III)和Dy(III)的化合物进行的交流磁化率测量表明，磁化强度存在缓慢弛豫，且在零场中有磁量子隧穿现象。
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