Spin transition in the molecular heterospin complex of Cu(hfac)2 with 4,4,5,5-tetramethyl-2-(1-methylpyrazol-5-yl)-4,5-dihydroimidazole-1-oxyl 3-oxide
作者:S. V. Fokin、E. T. Kostina、E. V. Tret’yakov、G. V. Romanenko、A. S. Bogomyakov、R. Z. Sagdeev、V. I. Ovcharenko
DOI:10.1007/s11172-013-0089-y
日期:2013.3
The synthesis, structure, and magnetic properties of the products of the reaction for Cu(hfac)2 (hfac is hexafluoroacetylacetonate) with spin-labeled nitronyl nitroxides 4,4,5,5-tetramethyl-2-(1-R-1H-pyrazol-5-yl)-3-imidazoline-1-oxyl 3-oxides L5/R (R = Me, Et, Pr, Bu), viz., binuclear complex [Cu(hfac)2L5/Me]2 and chain polymer complexes [Cu(hfac)2L5/R]n, are described. The polymer heterospin chains are built according to “head-to-head” (R = Me, Et, Pr, Bu) and “head-to-tail” (R = Pr, Bu) motifs. Compound [Cu(hfac)2L5/Me]2 is characterized by the ability to reveal the reversible effect of thermally induced spin transition at a temperature about 75 K (without hysteresis). In the set of heterospin CuII compounds with spin-labeled pyrazoles, this is the earlier unknown example of a molecular complex exhibiting a similar magnetic anomaly.
描述了Cu(hfac)2(hfac为六氟乙酰乙酮)与自旋标记的硝基含氮氧化物4,4,5,5-四甲基-2-(1-R-1H-吡唑-5-基)-3-咪唑啉-1-氧基-3-氧化物L5/R(R = 甲基、乙基、丙基、丁基)反应的产物的合成、结构和磁性特征,即二核络合物[Cu(hfac)2L5/Me]2和链聚合物络合物[Cu(hfac)2L5/R]n。这些聚合物异自旋链是按照“头对头”(R = 甲基、乙基、丙基、丁基)和“头对尾”(R = 丙基、丁基)结构构建的。化合物[Cu(hfac)2L5/Me]2具有在约75 K(无滞后现象)时揭示热诱导自旋转变的可逆效应的能力。在一组带有自旋标记吡唑的异自旋CuII化合物中,这是一个早期未知的分子络合物示例,表现出类似的磁性异常。