Title: Magnetic 3d–4f Chiral Clusters Showing Multimetal Site Magneto-Chiral Dichroism

Authors: Xing Wang, Shi-Qiang Wang, Jia-Nan Chen, Jian-Hua Jia, Cheng Wang, Kevin Paillot, Ivan Breslavetz, La-Sheng Long, Lansun Zheng, Geert L. J. A. Rikken, Cyrille Train, Xiang-Jian Kong*, and Matteo Atzori*

Abstract: Here, we report the molecular self-assembly of hydroxido-bridged {Ln₅Ni₆} ((Ln³⁺ = Dy³⁺, Y³⁺) metal clusters by the reaction of enantiopure chiral ligands, namely, (R/S)-(2-hydroxy-3-methoxybenzyl)-serine), with Ni^II and Ln^III precursors. Single-crystal diffraction analysis reveals that these compounds are isostructural sandwich-like 3d–4f heterometallic clusters showing helical chirality. Direct current magnetic measurements on {Dy₅Ni₆} indicates ferromagnetic coupling between Dy^III and Ni^II centers, whereas those on {Y₅Ni₆} denote that the Ni^II centers are antiferromagnetically coupled and/or magnetically anisotropic. Magneto-chiral dichroism (MChD) measurements on {Dy₅Ni₆} and its comparison to that of {Y₅Ni₆} provide the first experimental observation of intense multimetal site MChD signals in the visible–near-infrared region. Moreover, the comparison of MChD with natural and magnetic circular dichroism spectra unambiguously demonstrate for the first time that the MChD signals associated with the Ni^II d–d transitions are mostly driven by natural optical activity and those associated with the Dy^III f–f transitions are driven by magnetic optical activity.

Full-Link: https://pubs.acs.org/doi/10.1021/jacs.2c03049