Air-stable redox-active nanomagnets with lanthanide spins radical-bridged by a metal–metal bond

• Published in: Nature communications Vol. 10; no. 1; p. 571
• Main Authors: Liu, Fupin, Velkos, Georgios, Krylov, Denis S., Spree, Lukas, Zalibera, Michal, Ray, Rajyavardhan, Samoylova, Nataliya A., Chen, Chia-Hsiang, Rosenkranz, Marco, Schiemenz, Sandra, Ziegs, Frank, Nenkov, Konstantin, Kostanyan, Aram, Greber, Thomas, Wolter, Anja U. B., Richter, Manuel, Büchner, Bernd, Avdoshenko, Stanislav M., Popov, Alexey A.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 04.02.2019; Nature Publishing Group; Nature Portfolio
• Subjects: 119/118; 140/131; 140/133; 140/58; 639/301/357/73; 639/638/161; 639/638/263/406/910; 639/638/298/920; Coercivity; Coupling (molecular); Electrochemistry; Electrons; Fullerenes; Humanities and Social Sciences; Lanthanides; Magnetism; Magnets; Metal-metal bonding; Metals; multidisciplinary; Radicals; Science; Science (multidisciplinary); Single electrons
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-019-08513-6

Engineering intramolecular exchange interactions between magnetic metal atoms is a ubiquitous strategy for designing molecular magnets. For lanthanides, the localized nature of 4 f electrons usually results in weak exchange coupling. Mediating magnetic interactions between lanthanide ions via radical bridges is a fruitful strategy towards stronger coupling. In this work we explore the limiting case when the role of a radical bridge is played by a single unpaired electron. We synthesize an array of air-stable Ln 2 @C 80 (CH 2 Ph) dimetallofullerenes (Ln 2  = Y 2 , Gd 2 , Tb 2 , Dy 2 , Ho 2 , Er 2 , TbY, TbGd) featuring a covalent lanthanide-lanthanide bond. The lanthanide spins are glued together by very strong exchange interactions between 4 f moments and a single electron residing on the metal–metal bonding orbital. Tb 2 @C 80 (CH 2 Ph) shows a gigantic coercivity of 8.2 Tesla at 5 K and a high 100-s blocking temperature of magnetization of 25.2 K. The Ln-Ln bonding orbital in Ln 2 @C 80 (CH 2 Ph) is redox active, enabling electrochemical tuning of the magnetism. Dilanthanide complexes that possess radical bridges exhibit enhanced magnetic exchange coupling, affording molecular magnets with high blocking temperatures. Here, the authors explore a series of dilanthanide-encapsulated fullerenes where the radical bridge is taken to its limit and the role is played by a single unpaired electron.