远程取代基对具有钳型配体的单核钴（II）配合物的慢磁弛豫的影响。
Effect of the distant substituent on the slow magnetic relaxation of the mononuclear Co(ii) complex with pincer-type ligands.
作者信息
Rajnák Cyril, Titiš Ján, Moncol' Ján, Boča Roman
机构信息
Department of Chemistry, Faculty of Natural Sciences, University of SS Cyril and Methodius, 917 01 Trnava, Slovakia.
Institute of Inorganic Chemistry, Slovak University of Technology, 812 37 Bratislava, Slovakia.
出版信息
Dalton Trans. 2020 Apr 7;49(14):4206-4210. doi: 10.1039/d0dt00096e.
A hexacoordinated complex Co(pydm)22 from the family of pincer complexes was prepared and structurally characterized. The complex behaves as an S = 3/2 spin system with a considerable zero-field splitting parameter D/hc ∼ +50 cm-1. The AC susceptibility measurements show a slow magnetic relaxation with three relaxation channels: at the low-frequency (LF), intermediate-frequency (IF) and high-frequency (HF) domains. At T = 2.0 K and an external field BDC = 0.25 T, the relaxation times of the individual modes are τ(LF) = 282 ms, τ(IF) = 3.1 ms, and τ(HF) = 0.16 ms, and the mole fractions of the slowly relaxing species are x(LF) = 0.19, x(IF) = 0.45, and x(HF) = 0.37. A comparison with the analogous complex Co(pydm)22 possessing a demethylated counter anion and identical metal cation shows that even small modifications in the composition of SIMs are no longer underestimated for the slow magnetic relaxation.
制备并对来自钳形配合物家族的六配位配合物Co(pydm)₂₂进行了结构表征。该配合物表现为一个S = 3/2自旋体系，具有相当大的零场分裂参数D/hc ∼ +50 cm⁻¹。交流磁化率测量显示出具有三个弛豫通道的慢磁弛豫：在低频（LF）、中频（IF）和高频（HF）区域。在T = 2.0 K和外场BDC = 0.25 T时，各个模式的弛豫时间分别为τ(LF) = 282 ms、τ(IF) = 3.1 ms和τ(HF) = 0.16 ms，慢弛豫物种的摩尔分数分别为x(LF) = 0.19、x(IF) = 0.45和x(HF) = 0.37。与具有去甲基化抗衡阴离子和相同金属阳离子的类似配合物Co(pydm)₂₂的比较表明，即使是单离子磁体（SIMs）组成中的微小变化，对于慢磁弛豫而言也不再被低估。
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