Fine-Tuning Ligand to Modulate the Magnetic Anisotropy in a Carboxylate-Bridged Dy2 Single-Molecule Magnet System

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• 作者：Yu-Ling Wang ; Chang-Bao Han ; Yi-Quan Zhang ; Qing-Yan Liu ; Cai-Ming Liu ; Shun-Gao Yin
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 6, 2016
• 年：2016
• 卷：55
• 期：11
• 页码：5578-5584
• 全文大小：460K
• 年卷期：0
• ISSN：1520-510X

文摘

A series of dinuclear Dy(III) compounds with the general formula [Dy₂(μ₂-anthc)₄(anthc)₂(L)₂] (anthc^– = 9-anthracenecarboxylate, L = 2,2′-bipyridyl (1), 1,10-phenanthroline (2), and 4,7-dimethyl-1,10-phenanthroline (3)) were synthesized and magnetically characterized. These compounds exhibit single-molecule magnet (SMM) behavior in the absence of the direct-current field, which is rarely observed for carboxylate-bridged dinuclear Dy₂ system. With the first coordination sphere of Dy(III) centers being fixed, the energy barrier was modulated by sequentially modifying the terminal neutral L ligands in this Dy₂ system. Theoretical calculations revealed that the symmetry of the charge distribution surrounding the Dy(III) centers in 1–3 is the decisive factor to determine the relaxation of the SMMs. The combination of the larger charge distribution along the magnetic axis and lower charge distribution in the equatorial plane (hard plane) formed by five coplanar coordination atoms including two N atoms provided by an L ligand led to a strong easy-axis ligand field in these compounds. This work presents a rational method to modulate the dynamic magnetic relaxation of the lanthanide SMMs through fine-tuning electrostatic potential of the atoms on the hard plane.