A supramolecular chain of dimeric Dy single molecule magnets decorated with azobenzene ligands. Issue 42 (15th October 2019) - Huang, Gang
Abstract : Dy III dimers decorated with photo-isomerizable azobenzene ligands behave as single-molecule magnets and self-organize into a supramolecular chain. Ab initio calculations, magnetic and optical properties are reported. Abstract : We report the synthesis, ab initio calculations, magnetic and optical characterization of a Dy III -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 J states of the 6 H15/2 level of Dy III ions, the presence of low-lying excited M J 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.