Exchange-coupled terbium-radical complex Tb-phNO showing slow reversal of magnetization
Exchange-coupled terbium-radical complex Tb-phNO showing slow reversal of magnetization
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DOI：
10.1016/j.poly.2017.02.031
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发表时间：
2017-11-04
期刊：
影响因子：
2.6
通讯作者：
Ishida, Takayuki
中科院分区：
文献类型：
--
作者：
Kanetomo, Takuya;Yasui, Masanori;Ishida, Takayuki
合成了一种新的铽氮氧化合物[Tb-II（hfac）（3）（phNO）（H2O）]（phNO =叔丁基苯基氮氧化合物，hfac = 1，1，1，5，5，5-六氟戊烷-2，4-二酮），旨在开发具有强铁磁交换耦合的4f-2 p化合物。在一个晶胞中有两个晶体学上独立的分子。在H-dC = 2000 Oe处的交流磁化率显示出双chi（m）”峰，并伴有频率依赖性。对于高温峰系列，U-eff（（1））/k（B）= 46.3（7）K，τ（（1））（0）= 1.9（3）× 10（-9）s;对于高温峰系列，U-eff（（1））/k（B）= 21（2）K，τ（1）（0）= 13（9）× 10（-8）s（低温峰系列）。每个分子都被证明是潜在的单分子磁体（SMM）。相反，相应的镝（III）类似物没有表现出有意义的异相交流磁化率。在由于直接自由基配位键的强交换耦合机制中，全分子电子计数可以提供一个有用的判据来预测Kramers分子作为潜在的SMM候选者。(C)2017爱思唯尔有限公司版权所有。
A novel terbium(III)-nitroxide complex [Tb-II(hfac)(3)(phNO)(H2O)] (phNO = tert-butyl phenyl nitroxide, hfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate) was synthesized towards development of 4f-2p compounds with strong ferromagnetic exchange coupling. There are two crystallographically independent molecules in a unit cell. The ac magnetic susceptibility at H-dC = 2000 Oe showed double chi(m)" peaks accompanied by frequency dependence and afforded U-eff((1))/k(b) = 46.3(7) K with tau((1))(0) = 1.9(3) x 10(-9) s for the high temperature peak series and U-eff((1))/k(b) = 21(2) K with tau((1))(0) = 13(9) x 10(-8) s for the low-temperature peak series. Every molecule is proven to behave as a potential single-molecule magnet (SMM). In contrast, the corresponding dysprosium(III) analogue did not exhibit meaningful out-of-phase ac magnetic susceptibility. In the strongly exchange-coupled regime owing to the direct radical coordination bond, the whole molecular electron counting may provide a useful criterion to predict Kramers molecules as potential SMM candidates. (C) 2017 Elsevier Ltd. All rights reserved.