A high-frequency EPR study of magnetic anisotropy and intermolecular interactions of Co(II) ions
A high-frequency EPR study of magnetic anisotropy and intermolecular interactions of Co(II) ions
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DOI：
10.1016/j.poly.2021.115389
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发表时间：
2021-11
期刊：
影响因子：
2.6
通讯作者：
L. Spillecke;Shalini Tripathi;C. Koo;Mursaleem Ansari;S. Vaidya;Amaleswari Rasamsetty;T. Mallah
中科院分区：
文献类型：
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作者：
L. Spillecke;Shalini Tripathi;C. Koo;Mursaleem Ansari;S. Vaidya;Amaleswari Rasamsetty;T. Mallah
对于一类分子式为[Co(L1)4]X2(其中L1=硫脲（NH2CSNH2）， X = I (1), Br(2)和[Co(L1)4]（SiF6)(3)）的配合物，改变晶格中的阴离子会在[CoS4]2+核中引起明显的结构畸变。通过HF-EPR研究，定量测定了1 - 3的磁各向异性(D)，分别为- 153(2),- 168(5)和< -400 GHz。此外，通过实验确定了分子间的交换相互作用，其中1（-5.5 GHz）和2（-4.1 GHz）发生了反铁磁交换，3（+3.5 GHz）发生了铁磁相互作用（基于h = -JS1S2）。利用DFT方法在模型配合物1上计算交换相互作用，揭示了反铁磁交换相互作用的存在，与实验观察一致。总的来说，本研究提供了令人信服的实验证据，证明第一配位球和第二配位球对Co（II）离子的磁各向异性和交换相互作用有相当大的影响。
Changing the anion in a crystal lattice induces distinct structural distortions in the [CoS4]2+core for a family of complexes with the general molecular formula [Co(L1)4]X2, where L1= thiourea (NH2CSNH2) and X = I (1), Br (2), and [Co(L1)4](SiF6) (3). The magnetic anisotropy (D) for1–3was quantitatively determined with a magnitude of −153(2), −168(5) and < -400 GHz, respectively, by HF-EPR investigation. Also, intermolecular exchange interactions were determined experimentally, whereby an antiferromagnetic exchange for1(-5.5 GHz) and2(-4.1 GHz), and a ferromagnetic interaction for3(+3.5 GHz) are witnessed (based onH = -JS1S2). The exchange interactions, computed using DFT methods on a model complex of1, disclose the presence of an antiferromagnetic exchange interaction, consistent with the experimental observation. Overall, the present study provides convincing experimental evidence for the sizable influence not only of the first but also of the second coordination sphere on the magnetic anisotropy and exchange interactions of Co(II) ions.