Bistability of Magnetization without Spin-Transition in a High-Spin Cobalt(II) Complex due to Angular Momentum Quenching
Bistability of Magnetization without Spin-Transition in a High-Spin Cobalt(II) Complex due to Angular Momentum Quenching
复制标题
DOI：
10.1021/ja808448j
复制
发表时间：
2009-04-08
影响因子：
15
通讯作者：
Yoshizawa, Kazunari
中科院分区：
文献类型：
--
作者：
Juhasz, Gergely;Matsuda, Ryotaro;Yoshizawa, Kazunari
[Co(NO3)(2)L] （L: 2,6-二（吡唑-1-酰基）吡嗪）(1)磁化率在228 ~ 240 K之间表现出突变和迟滞。光谱和XRD测试结果表明，I在整个温度范围内均处于高自旋态。因此，观察到的磁滞不是由于自旋跃迁，而是对应于对磁化率贡献的角动量的部分猝灭。低温和高温形式1的晶体学测量，结合DFT计算，表明配位硝酸盐离子在跃迁时的对称扭转是轨道猝灭机制的最重要因素。利用这种淬灭来控制磁性能可以是设计具有磁性功能的过渡金属配合物而不改变其自旋或氧化态的新方法。
[Co(NO3)(2)L] (L: 2,6-di(pyrazol-1-yl)pyrazine) (1) exhibits an abrupt transition with hysteresis in magnetic susceptibility between 228 and 240 K. The results of spectroscopic and XRD measurements showed that I is in the high spin state in the whole temperature range. Therefore the observed hysteresis is not due to a spin transition but corresponds to a partial quenching of the angular momentum contribution to the magnetic susceptibility. Crystallographic measurements on the low- and high-temperature form of 1, combined with DFT calculations, showed that a symmetric twisting of the coordinating nitrate ions upon the transition is the most important factor in the orbital quenching mechanism. Utilizing such quenching to control magnetic properties can be a new approach to engineer transition metal complexes with magnetic functionalities without changing their spin or oxidation state.