Tailored Lewis Acid Sites for High-Temperature Supported Single-Molecule Magnetism

Moritz Bernhardt; Maciej D Korzyński; Zachariah J Berkson; Fabrice Pointillart; Boris Le Guennic; Olivier Cador; Christophe Copéret

doi:10.1021/jacs.3c02730

Tailored Lewis Acid Sites for High-Temperature Supported Single-Molecule Magnetism

J Am Chem Soc. 2023 Jun 14;145(23):12446-12451. doi: 10.1021/jacs.3c02730. Epub 2023 Jun 1.

Authors

Moritz Bernhardt¹, Maciej D Korzyński¹, Zachariah J Berkson¹, Fabrice Pointillart², Boris Le Guennic², Olivier Cador², Christophe Copéret¹

Affiliations

¹ Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog Weg 1-5/10, 8093 Zürich, Switzerland.
² Univ Rennes CNRS, ISCR (Institut des Sciences Chimiques de Rennes), UMR 6226, 35000 Rennes, France.

Abstract

Generating or even retaining slow magnetic relaxation in surface immobilized single-molecule magnets (SMMs) from promising molecular precursors remains a great challenge. Illustrative examples are organolanthanide compounds that show promising SMM properties in molecular systems, though surface immobilization generally diminishes their magnetic performance. Here, we show how tailored Lewis acidic Al(III) sites on a silica surface enable generation of a material with SMM characteristics via chemisorption of (Cp^ttt)₂DyCl ((Cp^ttt)^- = 1,2,4-tri(tert-butyl)-cyclopentadienide). Detailed studies of this system and its diamagnetic Y analogue indicate that the interaction of the metal chloride with surface Al sites results in a change of the coordination sphere around the metal center inducing for the dysprosium-containing material slow magnetic relaxation up to 51 K with hysteresis up to 8 K and an effective energy barrier (U_eff) of 449 cm^-1, the highest reported thus far for a supported SMM.