Magnetic anisotropy of two tetrahedral Co( ii )-halide complexes with triphenylphosphine ligands
Magnetic anisotropy of two tetrahedral Co( ii )-halide complexes with triphenylphosphine ligands
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两个四面体Co(ii)卤化物与三苯基膦配体的磁各向异性
DOI：
10.1039/d2dt00121g
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发表时间：
2022
影响因子：
4
通讯作者：
Xue, Zi-Ling
中科院分区：
文献类型：
--
作者：
Lv, Wei;Cui, Hui-Hui;Chen, Lei;Zhang, Yi-Quan;Chen, Xue-Tai;Wang, Zhenxing;Ouyang, Zhong-Wen;Xue, Zi-Ling
近年来，配体的选择和单核配合物的几何构型控制对弛豫路径和阻断温度的影响在单离子磁体领域受到了广泛关注。为了研究配位环境对西姆斯的影响，合成了两个四配位单核Co（II）配合物[NEt 4][Co（PPh 3）X3]（X = Cl-，1; Br-，2），并通过X射线单晶学、磁性测量、高频-场EPR（HF-EPR）谱和理论计算进行了研究.这两种配合物都属于立方空间群Pa（No. 205），含有一个轻微扭曲的四面体部分，通过[Co（PPh 3）X3]−阴离子具有晶体学上强加的C3 v对称性。直流（dc）磁数据和HF-EPR光谱表明各向异性S = 3/2自旋基态的Co（II）离子与易平面各向异性1和2。进行从头计算以确认1和2的正磁各向异性。频率和温度依赖的交流（ac）磁化率测量显示，在施加的直流磁场1和2缓慢的磁弛豫。最后，将1和2的磁性与具有[CoAB 3]部分的其他Co（II）络合物的磁性进行比较。
Recently, the choice of ligand and geometric control of mononuclear complexes, which can affect the relaxation pathways and blocking temperature, have received wide attention in the field of single-ion magnets (SIMs). To find out the influence of the coordination environment on SIMs, two four-coordinate mononuclear Co(II) complexes [NEt4][Co(PPh3)X3] (X = Cl−, 1; Br−, 2) have been synthesized and studied by X-ray single crystallography, magnetic measurements, high-frequency and -field EPR (HF-EPR) spectroscopy and theoretical calculations. Both complexes are in a cubic space group Pa (No. 205), containing a slightly distorted tetrahedral moiety with crystallographically imposed C3v symmetry through the [Co(PPh3)X3]− anion. The direct-current (dc) magnetic data and HF-EPR spectroscopy indicated the anisotropic S = 3/2 spin ground states of the Co(II) ions with the easy-plane anisotropy for 1 and 2. Ab initio calculations were performed to confirm the positive magnetic anisotropies of 1 and 2. Frequency- and temperature-dependent alternating-current (ac) magnetic susceptibility measurements revealed slow magnetic relaxation for 1 and 2 at an applied dc field. Finally, the magnetic properties of 1 and 2 were compared to those of other Co(II) complexes with a [CoAB3] moiety.