Enhancement of Magneto-Chiral Dichroism Intensity by Chemical Design: The Key Role of Magnetic-Dipole Allowed Transitions
Chong-Yang Li, Langit Cahya Adi, Kévin Paillot, Ivan Breslavetz, La‐Sheng Long, Lan‐Sun Zheng, G. L. J. A. Rikken, Cyrille Train, Xiang‐Jian Kong, Matteo Atzori
Abstract
Here we report on the strong magneto-chiral dichroism (MChD) detected through visible and near-infrared light absorption up to 5.0 T on {Er 5 Ni 6 } metal clusters obtained by reaction of enantiopure chiral ligands and Ni II and Er III precursors. Single-crystal diffraction analysis reveals that these compounds are 3 d– 4 f heterometallic clusters, showing helical chirality. MChD spectroscopy reveals a high g MChD dissymmetry factor of ca. 0.24 T –1 ( T = 4.0 K, B = 1.0 T) for the 4 I 13/2 ← 4 I 15/2 magnetic-dipole allowed electronic transition of the Er III centers. This record value is 1 or 2 orders of magnitude higher than that of the d–d electronic transitions of the Ni II ions and the others f–f electric-dipole induced transitions of the Er III centers. These findings clearly show the key role that magnetic-dipole allowed transitions have in the rational design of chiral lanthanide systems showing strong MChD.