Zhang Sheng, Shen Nan, Zhang Jiangwei, Xu Fang, Zhang Jin, Tang Jiamin, Hu Dengwei, Yin Bing, Chen Sanping
Faculty of Chemistry and Chemical Engineering, Engineering Research Center of Advanced Ferroelectric Functional Materials, Key Laboratory of Phytochemistry of Shaanxi Province, Baoji University of Arts and Sciences, 1 Hi-Tech Avenue, Baoji, Shaanxi 721013, China.
Dalton Trans. 2021 Jan 19;50(2):624-637. doi: 10.1039/d0dt03477k.
Solvent responsive magnets comprise a class of molecule-based materials where lattice solvent driven structural transformation leads to the switching of magnetic properties. Herein, we present a special type of magnet where single-crystal to single-crystal (SCSC) transformations within mononuclear DyIII compounds result in the switching of DyIII single-molecule magnets (SMMs). This structural transformation involves lattice solvents which leads to significant changes in the color and magnetic properties. Additionally, the relaxation dynamics of mononuclear DyIII compounds are perceptibly fine-tuned by the modification of β-diketonate ligands. The uniaxial magnetic anisotropies, magneto-structural correlations and the relaxation mechanism were investigated by magnetic studies and ab initio calculations. These experimental and theoretical studies indicate that compound 2 exhibits the best magnetic properties in compounds 1-4. The experimental observation is supported by the theoretical prediction of QTM time (τZeeQTM) as theτZeeQTM of 2 is remarkably longer than those of the other three compounds by an order of magnitude. This means that, compared with 1, 3, and 4, the magnetic relaxation of 2 is significantly slower. Meanwhile, 2 has the largest value of axial ESP (the axial electrostatic potential), which supports the smallest gXY value in these compounds, resulting in better SMM properties. The present results offer a systematic synthesis regulation to change the magnetization dynamics and further understand magneto-structural correlations for DyIII SMMs.
溶剂响应性磁体包括一类基于分子的材料，其中晶格溶剂驱动的结构转变导致磁性能的切换。在此，我们展示了一种特殊类型的磁体，其中单核DyIII化合物内的单晶到单晶（SCSC）转变导致DyIII单分子磁体（SMM）的切换。这种结构转变涉及晶格溶剂，这会导致颜色和磁性能发生显著变化。此外，单核DyIII化合物的弛豫动力学通过β-二酮配体的修饰得到明显微调。通过磁性研究和从头算计算研究了单轴磁各向异性、磁结构相关性和弛豫机制。这些实验和理论研究表明，化合物2在化合物1-4中表现出最佳的磁性能。实验观察结果得到了QTM时间（τZeeQTM）理论预测的支持，因为2的τZeeQTM比其他三种化合物的τZeeQTM长一个数量级。这意味着，与1、3和4相比，2的磁弛豫明显更慢。同时，2具有最大的轴向ESP值（轴向静电势），这支持了这些化合物中最小的gXY值，从而产生更好的SMM性能。目前的结果提供了一种系统的合成调控方法，以改变磁化动力学并进一步理解DyIII SMM的磁结构相关性。
