Magneto-Chiral Dichroism in a One-Dimensional Assembly of Helical Dysprosium(III) Single-Molecule Magnets
Maria Sara Raju, Kais Dhbaibi, Maxime Grasser, Vincent Dorcet, Ivan Breslavetz, Kévin Paillot, Nicolas Vanthuyne, Olivier Cador, Geert L. J. A. Rikken, Boris Le Guennic, Jeanne Crassous, Fabrice Pointillart, Cyrille Train, Matteo Atzori
Abstract
Here we report magneto-chiral dichroism (MChD) detected through visible and near-infrared light absorption of a chiral dysprosium(III) coordination polymer. The two enantiomers of [Dy III (H6(py) 2 )(hfac) 3 ] n [H6(py) 2 = 2,15-bis(4-pyridyl)ethynylcarbo[6]helicene; hfac – = 1,1,1,5,5,5-hexafluoroacetylacetonate], where the chirality is provided by a functionalized helicene ligand, were structurally, spectroscopically, and magnetically investigated. Magnetic measurements reveal a slow relaxation of the magnetization, with differences between enantiopure and racemic systems rationalized on the basis of theoretical calculations. When the enantiopure complexes are irradiated with unpolarized light in a magnetic field, they exhibit multiple MChD signals associated with the f–f electronic transitions of Dy III, thus providing the coexistence of MChD-active absorptions and single-molecule-magnet (SMM) behavior. These findings clearly show the potential that rationally designed chiral SMMs have in enabling the optical readout of magnetic memory through MChD.