Field-induced slow relaxation of magnetization in a pentacoordinate Co(II) compound [Co(phen)(DMSO)Cl2].
Field-induced slow relaxation of magnetization in a pentacoordinate Co(II) compound [Co(phen)(DMSO)Cl2].
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DOI：
10.1039/c5dt02162f
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发表时间：
2015-08
影响因子：
4
通讯作者：
Ivan Nemec;Raphael Marx;R. Herchel;P. Neugebauer;J. van Slageren;Z. Trávníček
中科院分区：
文献类型：
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作者：
Ivan Nemec;Raphael Marx;R. Herchel;P. Neugebauer;J. van Slageren;Z. Trávníček
采用实验方法（SQUID磁强计和HF-EPR光谱）和理论方法（DFT和CASSCF计算）研究了五坐标[Co(phen)(DMSO)Cl2]化合物（phen = 1,10′-菲罗啉，DMSO =二甲亚砜）的静态和动态磁性能。温度场相关磁化测量结果表明，所研究的化合物具有较大的负各向异性(D = -17（1) cm(-1)）和较大的菱形（E/D = 0.24(5)），实验结果与从头计算结果（D = -17.7 cm(-1), E/D = 0.31）一致。在HF-EPR测量中未观察到双偶态共振，但证实了大的正交性(DEPR = -17.7 cm（-1)（由CASSCF计算修正），E/DEPR = 0.33）。仅在非零静态磁场（B = 0.1 T）下观察到频率相关的非相位磁化率信号，并根据实验数据推导出磁化慢弛豫的参数：采用Debye模型计算自旋反转势势能Ueff = 10.4 K和弛豫时间τ0 = 5.69 × 10(-9) s，或采用简化模型计算Ueff = 21.4 ~ 40.3 K和τ0 = 0.248 ~ 58.3 × 10(-9) s。
The static and dynamic magnetic properties of a pentacoordinate [Co(phen)(DMSO)Cl2] compound (phen = 1,10'-phenanthroline, DMSO = dimethyl sulfoxide) were thoroughly studied by experimental (SQUID magnetometry and HF-EPR spectroscopy) and theoretical methods (DFT and CASSCF calculations). It has been found from temperature/field-dependent magnetization measurements that the studied compound possesses a large and negative magnetic anisotropy (D = -17(1) cm(-1)) with large rhombicity (E/D = 0.24(5)), and these experimental results are in agreement with ab initio calculations (D = -17.7 cm(-1), E/D = 0.31). Interdoublet resonances were not observed in the HF-EPR measurements, but the large rhombicity was confirmed (DEPR = -17.7 cm(-1) (fixed from CASSCF calculations), E/DEPR = 0.33). A frequency dependent out-of-phase susceptibility signal was observed only in a non-zero static magnetic field (B = 0.1 T) and the following parameters of slow-relaxation of magnetisation were derived from the experimental data: either the energy of spin reversal barrier, Ueff = 10.4 K, and the relaxation time, τ0 = 5.69 × 10(-9) s using the Debye model, or Ueff = 21.4-40.3 K and τ0 = 0.248-58.3 × 10(-9) based on a simplified model.