Shao Feng, Cahier Benjamin, Rivière Eric, Guillot Régis, Guihéry Nathalie, Campbell Victoria E, Mallah Talal
Institut de Chimie Moléculaire et des Matériaux d'Orsay, CNRS, Université Paris Sud, Université Paris Saclay , 91405 Orsay Cedex, France.
Laboratiore de Chimie et Physique Quantiques, Université Toulouse III , 118 route de Narbonne, 31062 Toulouse, France.
Inorg Chem. 2017 Feb 6;56(3):1104-1111. doi: 10.1021/acs.inorgchem.6b01966. Epub 2017 Jan 12.
This paper describes the correlation between Ising-type magnetic anisotropy and structure in trigonal bipyramidal Co(II) complexes. Three sulfur-containing trigonal bipyramidal Co(II) complexes were synthesized and characterized. It was shown that we can engineer the magnitude of the Ising anisotropy using ligand field theory arguments in conjunction with structural parameters. To prepare this series of compounds, we used, on the one hand, a tetradentate ligand containing three sulfur atoms and one amine (NS) and on the other hand three different axial ligands, namely, Cl, Br, and NCS. The organic ligand imposes a trigonal bipyramidal arrangement with the three sulfur atoms lying in the trigonal plane with long Co-S bond distances. The magnetic properties of the compounds were measured, and ab initio calculations were used to analyze the anisotropy parameters and perform magneto-structural correlations. We demonstrate that a smaller axial zero-field splitting parameter leads to slower relaxation time when the symmetry is strictly axial, while the presence of very weak rhombicity decreases the energy barrier and speeds the relaxation of the magnetization.
本文描述了三角双锥Co(II)配合物中伊辛型磁各向异性与结构之间的相关性。合成并表征了三种含硫三角双锥Co(II)配合物。结果表明，我们可以结合配体场理论观点和结构参数来设计伊辛各向异性的大小。为制备这一系列化合物，一方面我们使用了一种含三个硫原子和一个胺（NS）的四齿配体，另一方面使用了三种不同的轴向配体，即Cl、Br和NCS。有机配体形成一种三角双锥排列，三个硫原子位于三角平面，Co-S键距较长。测量了化合物的磁性，并使用从头算来分析各向异性参数并进行磁结构关联。我们证明，当对称性严格为轴向时，较小的轴向零场分裂参数会导致弛豫时间变慢，而非常弱的菱形度的存在会降低能垒并加快磁化弛豫。
