Fluoride-bridged dinuclear dysprosium complex showing single-molecule magnetic behavior: supramolecular approach to isolate magnetic molecules

• Published in: RSC advances Vol. 12; no. 33; pp. 2128 - 21286
• Main Authors: Wu, Dong-Fang, Takahashi, Kiyonori, Fujibayashi, Masaru, Tsuchiya, Naoto, Cosquer, Goulven, Huang, Rui-Kang, Xue, Chen, Nishihara, Sadafumi, Nakamura, Takayoshi
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 02.08.2022; The Royal Society of Chemistry
• Subjects: Bamboo; bamboos; Cations; Chemistry; Dysprosium; Ferromagnetism; Fluorides; ligands; magnetic fields; Magnetic induction; magnetic materials; Magnetic permeability; Magnetic properties; Magnetic relaxation; magnetic susceptibility; Quantum tunnelling; Sodium; temperature; Temperature dependence
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/d2ra04119g

Using Na-encapsulated benzo[18]crown-6 (Na)(B18C6) as a counter cation, we successfully magnetically isolated a fluoride-bridging Dy dinuclear complex {[(PW 11 O 39 )Dy(H 2 O) 2 ] 2 F} (Dy 2 POM) with lacunary Keggin ligands. (Na)(B18C6) formed two types of tetramers through C-H O, π π and C-H π interactions, and each tetramer aligned in one dimension along the c -axis to form two types of channels. One channel was partially penetrated by a supramolecular cation from the ± a -axis direction, dividing the channel in the form of a "bamboo node". Dy 2 POM was spatially divided by this "bamboo node," which magnetically isolated one portion from the other. The temperature dependence of the magnetic susceptibility indicated a weak ferromagnetic interaction between the Dy ions bridged by fluoride. Dy 2 POM exhibited the magnetic relaxation characteristics of a single-molecule magnet, including the dependence of AC magnetic susceptibility on temperature and frequency. Magnetic relaxation can be described by the combination of thermally active Orbach and temperature-independent quantum tunneling processes. The application of a static magnetic field effectively suppressed the relaxation due to quantum tunneling. (Na + )(benzo[18]crown-6) forms a bamboo-like supramolecular architecture within the crystal. Dinuclear Dy complexes with polyoxometalate ligands embedded between bamboo nodes exhibited a clear single-molecule magnet (SMM) response.