Manipulating the Relaxation of Quasi-D4d Dysprosium Compounds through Alternation of the O-Donor Ligands

Mei Guo (1) , Jianfeng Wu (2) , Olivier Cador (3) , Jingjing Lu (4) , Bing Yin (5) , Boris Le Guennic (3) , Jinkui Tang (4)

1 UCAS - University of Chinese Academy of Sciences [Beijing]
2 NPU - Northwestern Polytechnical University [Xi'an]
3 ISCR - Institut des Sciences Chimiques de Rennes
4 Changchun Institute of Applied Chemistry - State Key Laboratory of Polymer Physics and Chemistry
5 NWU - North-West University [Vaal Triangle Campus, Vanderbijlpark, South Africa]

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.

Domaines: Chimie de coordination

Mei Guo, Jianfeng Wu, Olivier Cador, Jingjing Lu, Bing Yin, et al.. Manipulating the Relaxation of Quasi-D4d Dysprosium Compounds through Alternation of the O-Donor Ligands. Inorganic Chemistry, 2018, 57 (8), pp.4534-4542. ⟨10.1021/acs.inorgchem.8b00294⟩. ⟨hal-01771520⟩