Strong magnetochiral dichroism for visible light emission in a rationally designed paramagnetic enantiopure molecule

Abstract

Magnetochiral dichroism (MChD) in chiral materials is a nonreciprocal directional dichroism producing optical absorption/emission differences for unpolarized (or linearly polarized) light propagating parallel and antiparallel to a magnetic field; this is an intriguing optical phenomenon enabled by coupling between chirality and magnetism. Since ubiquitous unpolarized light can be coupled with chirality of materials in a magnetic field, MChD has been attracting attention as a potential source for asymmetric photochemical reactions and as an application source for novel magneto-optical devices. However, it has been weakly observed in the visible light region, which is of the order of ${10}^{\ensuremath{-}2}\ensuremath{-}{10}^{\ensuremath{-}1}%$ for the corresponding signal, and prevents further applications. In this study, we demonstrate a strong MChD for visible light emission based on the microscopic mechanism in a terbium(III) chiral complex with highly symmetrical nona-coordinated geometry. The MChD signal reaches $\ensuremath{\sim}16%$ at 14 T of the luminescence intensity, involving the development of magnetization under magnetic fields.