title: Self-assembly of a 3d-5f trinuclear single-molecule magnet from a pentavalent uranyl complex.
abstract: Mixed-metal uranium compounds are very attractive candidates in the design of single-molecule magnets (SMMs), but only one 3d-5f hetero-polymetallic SMM containing a uranium center is known. Herein, we report two trimeric heterodimetallic 3d-5f complexes self-assembled by cation-cation interactions between a uranyl(V) complex and a TPA-capped M(II)  complex (M=Mn (1), Cd (2); TPA=tris(2-pyridylmethyl)amine). The metal centers were strategically chosen to promote the formation of discrete molecules rather than extended chains. Compound 1, which contains an almost linear {MnOUOMn} core, exhibits SMM behavior with a relaxation barrier of 81±0.5 K-the highest reported for a mono-uranium system-arising from intramolecular Mn-U exchange interactions combined with the high Ising anisotropy of the uranyl(V) moiety. Compound 1 also exhibits an open magnetic hysteresis loop at temperatures less than 3 K, with a significant coercive field of 1.9 T at 1.8 K.
authors.affiliation: Laboratoire de Reconnaissance Ionique et Chimie de Coordination SCIB, UMR-E3 CEA-UJF, INAC, CEA-Grenoble, 17 rue des Martyrs, F-38054 Grenoble Cedex 09 (France).
authors.forename: Lucile
authors.initials: L
authors.lastname: Chatelain
authors.forename: James P S
authors.initials: JP
authors.lastname: Walsh
authors.forename: Jacques
authors.initials: J
authors.lastname: Pécaut
authors.forename: Floriana
authors.initials: F
authors.lastname: Tuna
authors.forename: Marinella
authors.initials: M
authors.lastname: Mazzanti
keywords: exchange interactions; magnetism; polymetallic complexes; single-molecule magnets; uranium