Metal-Organic Framework of Lanthanoid Dinuclear Clusters Undergoes Slow Magnetic Relaxation

Abstract

Lanthanoid metal-organic frameworks (Ln-MOFs) can adopt a variety of new structures due to the large coordination numbers of Ln metal ions, and Ln-MOFs are expected to show new luminescence and magnetic properties due to the localized f electrons. In particular, some Ln metal ions, such as Dy(III) and Tb(III) ions, work as isolated quantum magnets when they have magnetic anisotropy. In this work, using 4,4′,4″-s-triazine-2,4,6-triyl-tribenzoic acid (H3TATB) as a ligand, two new Ln-MOFs, [Dy(TATB)(DMF)2] (1) and [Tb(TATB)(DMF)2] (2), were obtained. The Ln-MOFs contain Ln dinuclear clusters as secondary building units, and 1 underwent slow magnetic relaxation similar to single-molecule magnets.

Reversible Switching of Single-Molecule Magnetic Behaviour by Desorption/Adsorption of Solvent Ligand in a New Dy(III)-Based Metal Organic Framework

“…However, it is difficult for most 3D-MOFs to show slow magnetic relaxation because there are frequently existing exchange interactions and magnetic order ( Miyasaka et al, 2006 ; Bernot et al, 2009 ). For lanthanide MOFs, the exchange interaction between lanthanide ions is generally weak due to the effective shielding of unpaired electrons in the 4f orbital of the lanthanide ions ( Aulakh et al, 2015 ; Liu et al, 2015 ; Liu et al, 2016 ; Iwami et al, 2017 ; Castells-Gil et al, 2018 ). Furthermore, 4f ions contain various coordination geometries, most from six-to nine-coordination, which contribute to the design and adjustment of the structures ( Ruiz-Martínez et al, 2008 ; Song et al, 2012 ; Aulakh et al, 2015 ; Guo et al, 2017 ; Li et al, 2017 ; Wang et al, 2018 ).…”