Concomitant emergence of circularly polarized luminescence and single-molecule magnet behavior in chiral-at-metal Dy complex

Abstract

Circularly polarized luminescence (CPL) was evidenced for the first time in single crystals of a chiral-at-metal Dy(III) single-molecule magnet. This CPL is opposite for the enantiomers and was found to appear and become stronger at lower temperatures when the relaxation of the magnetization for the Dy centers is slower. The luminescence dissymmetry factor (g_lum up to ±0.18) was found to have little dependence on the emission angle which permitted observing a similar CPL for an ensemble of micro-crystals of random orientations. The investigated Dy(III) compounds consist of bimetallic ZnLn units assembled by a Schiff base ligand, control of the stereochemistry of the Ln center was achieved using chiral [3-(trifluoromethylhydroxymethylene)-camphorate]⁻ as anionic ligands. CPL was not found for the Eu(III) homologues.