A supramolecular chain of dimeric Dy single molecule magnets decorated with azobenzene ligands

Gang Huang (1) , Xiaohui Yi (1) , Frédéric Gendron (1) , Boris Le Guennic (1) , Thierry Guizouarn (1) , Carole Daiguebonne (1) , Guillaume Calvez (1) , Yan Suffren (1) , Olivier Guillou (1) , Kevin Bernot (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

We report the synthesis, ab initio calculations, magnetic and optical characterization of a Dy-based dimeric compound named DyAZO. The dimers self-organize into a supramolecular chain decorated with photo-isomerizable azobenzene ligands. DyAZO displays single-molecule magnet (SMM) behavior. However, ab initio calculations highlight a quite strong admixture of M states of the H level of Dy ions, the presence of low-lying excited M states and antiferromagnetic Dy-Dy dipolar coupling. This favors zero-field fast tunneling. Accordingly the Dy-doped analogue YDyAZO (5.5% Dy doping) displays enhanced magnetic relaxation with a hysteresis that is observed at 0.5 K. The influence of the cis- to trans-isomerization of the decorating azobenzene ligand on magnetic properties has been tested for both solid samples and solutions of DyAZO and YDyAZO. This provides hints for the synthesis of future Dy-based photo-isomerizable molecules.

Domains: Chemical Sciences

Gang Huang, Xiaohui Yi, Frédéric Gendron, Boris Le Guennic, Thierry Guizouarn, et al.. A supramolecular chain of dimeric Dy single molecule magnets decorated with azobenzene ligands. Dalton Transactions, 2019, 48 (42), pp.16053-16061. ⟨10.1039/c9dt03540k⟩. ⟨hal-02364866⟩