Guo Mei, Wu Jianfeng, Cador Olivier, Lu Jingjing, Yin Bing, Le Guennic Boris, Tang Jinkui
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry , Chinese Academy of Sciences , Changchun 130022 , P. R. China.
University of Chinese Academy of Sciences , Beijing , 100049 , P. R. China.
Inorg Chem. 2018 Apr 16;57(8):4534-4542. doi: 10.1021/acs.inorgchem.8b00294. Epub 2018 Apr 3.
Three mononuclear Dy complexes with the same auxiliary ligand Lz (2,4-diamino-6-pyridyl-1,3,5-triazine), [Dy(TTA)Lz] (1Dy) (TTA = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate), [Dy(acac)Lz]·CHOH·0.5HO (2Dy) (acac = acetylacetonate), and [Dy(MQ)Lz]Br·CHOH (3Dy) (HMQ = 2-methyl-8-quinolinol), have been synthesized through alteration of the ligands containing O donors. In all three complexes, the Dy ions are eight-coordinate and submitted to pseudo- D symmetry in the first coordination sphere. It is noteworthy that the TTA ligands in 1Dy are easily substituted by other bidentate capping ligands with O donors, leading to distinct magnetic properties, which were studied experimentally and via ab initio calculations. All three complexes were found to exhibit single-molecule magnet behavior with U of 22 cm (1Dy), 112 cm (2Dy), and 56 cm (3Dy) under zero applied dc field. Complex 1Dy demonstrates inferior SIM properties compared with 2Dy and 3Dy, which can be attributed to the strong electron-withdrawing effects of TTA ligands, as confirmed by theoretical calculations. However, butterfly-shaped magnetic hysteresis in 1Dy and 3Dy was observed at 1.9 K, while not in 2Dy.
通过改变含O供体的配体，合成了三种具有相同辅助配体Lz（2,4-二氨基-6-吡啶基-1,3,5-三嗪）的单核Dy配合物，即[Dy(TTA)Lz]（1Dy）（TTA = 4,4,4-三氟-1-(2-噻吩基)-1,3-丁二酮）、[Dy(acac)Lz]·CH₂OH·0.5H₂O（2Dy）（acac = 乙酰丙酮）和[Dy(MQ)Lz]Br·CH₂OH（3Dy）（HMQ = 2-甲基-8-喹啉醇）。在这三种配合物中，Dy离子均为八配位，且在第一配位球中呈伪D对称性。值得注意的是，1Dy中的TTA配体很容易被其他含O供体的双齿封端配体取代，从而导致明显不同的磁性质，对此进行了实验研究并通过从头算计算进行了分析。发现在零外加直流场下，这三种配合物均表现出单分子磁体行为，其U分别为22 cm⁻¹（1Dy）、112 cm⁻¹（2Dy）和56 cm⁻¹（3Dy）。与2Dy和3Dy相比，1Dy表现出较差的单分子磁体性质，理论计算证实这可归因于TTA配体的强吸电子效应。然而，在1.9 K时观察到1Dy和3Dy出现蝶形磁滞现象，而2Dy未出现。
