A trivalent 4f complex with two bis-silylamide ligands displaying slow magnetic relaxation

• Published in: Nature chemistry Vol. 15; no. 8; pp. 1100 - 1107
• Main Authors: Errulat, Dylan, Harriman, Katie L. M., Gálico, Diogo A., Kitos, Alexandros A., Mansikkamäki, Akseli, Murugesu, Muralee
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.08.2023; Nature Publishing Group
• Subjects: 639/638/263/406/939; 639/638/298/920; Analytical Chemistry; Anions; Anisotropy; Biochemistry; Cations; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Coordination numbers; Inorganic Chemistry; Ligands; Magnetic anisotropy; Magnetic induction; Magnetic relaxation; Magnets; Organic Chemistry; Physical Chemistry; Spectroscopy
• ISSN: 1755-4330; 1755-4349
• DOI: 10.1038/s41557-023-01208-y

The best-performing single-molecule magnets (SMMs) have historically relied on pseudoaxial ligands delocalized across several coordinated atoms. This coordination environment has been found to elicit strong magnetic anisotropy, but lanthanide-based SMMs with low coordination numbers have remained synthetically elusive species. Here we report a cationic 4 f complex bearing only two bis-silylamide ligands, Yb(III)[{N(SiMePh 2 ) 2 } 2 ][Al{OC(CF 3 ) 3 } 4 ], which exhibits slow relaxation of its magnetization. The combination of the bulky silylamide ligands and weakly coordinating [Al{OC(CF 3 ) 3 } 4 ] − anion provides a sterically hindered environment that suitably stabilizes the pseudotrigonal geometry necessary to elicit strong ground-state magnetic anisotropy. The resolution of the m J states by luminescence spectroscopy is supported by ab initio calculations, which show a large ground-state splitting of approximately 1,850 cm −1 . These results provide a facile route to access a bis-silylamido Yb(III) complex, and further underline the desirability of axially coordinated ligands with well-localized charges for high-performing SMMs. A trivalent 4 f cationic complex bearing two bis-silylamide ligands has been prepared that displays slow magnetic relaxation. The bulky ligands and weakly coordinating anion stabilize the pseudotrigonal geometry necessary to elicit strong ground-state magnetic anisotropy in this axially coordinated Yb(III) complex with well-localized charges.