Spin‐State Control in Dysprosium(III) Metallacrown Magnets via Thioacetal Modification

• Published in: Angewandte Chemie International Edition Vol. 63; no. 31; pp. e202404271 - n/a
• Main Authors: Deng, Wei, Wu, Si‐Guo, Ruan, Ze‐Yu, Gong, Ya‐Ping, Du, Shan‐Nan, Wang, Hai‐Ling, Chen, Yan‐Cong, Zhang, Wei‐Xiong, Liu, Jun‐Liang, Tong, Ming‐Liang
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 29.07.2024
• Edition: International ed. in English
• Subjects: Coercivity; Controllability; Dysprosium; Magnetic induction; Magnetic studies; magnetization dynamics; Magnets; metallacrown; Phenols; single-molecule magnet; Spin dynamics; spin state; thioacetal modification; metallacrown; single-molecule magnet; thioacetal modification; spin state; magnetization dynamics
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202404271

Integrating controllable spin states into single‐molecule magnets (SMMs) enables precise manipulation of magnetic interactions at a molecular level, but remains a synthetic challenge. Herein, we developed a 3d–4f metallacrown (MC) magnet [DyNi5(quinha)5(Clsal)2(py)8](ClO4) ⋅ 4H2O (H2quinha=quinaldichydroxamic acid, HClsal=5‐chlorosalicylaldehyde) wherein a square planar NiII is stabilized by chemical stacking. Thioacetal modification was employed via post‐synthetic ligand substitutions and yielded [DyNi5(quinha)5(Clsaldt)2(py)8](ClO4) ⋅ 3H2O (HClsaldt=4‐chloro‐2‐(1,3‐dithiolan‐2‐yl)phenol). Thanks to the additional ligations of thioacetal onto the NiII site, coordination‐induced spin state switching (CISSS) took place with spin state altering from low‐spin S=0 to high‐spin S=1. The synergy of CISSS effect and magnetic interactions results in distinct energy splitting and magnetic dynamics. Magnetic studies indicate prominent enhancement of reversal barrier from 57 cm−1 to 423 cm−1, along with hysteresis opening and an over 200‐fold increment in coercive field at 2 K. Ab initio calculations provide deeper insights into the exchange models and rationalize the relaxation/tunnelling pathways. These results demonstrate here provide a fire‐new perspective in modulating the magnetization relaxation via the incorporation of controllable spin states and magnetic interactions facilitated by the CISSS approach. Through thioacetal modification, a 3d–4f metallacrown with a square planar NiII successfully realized chemical‐induced coordination‐induced spin state switching (CISSS) and the spin state of NiII altering from low‐spin S=0 to high‐spin S=1. The synergy of CISSS effect and magnetic interactions results in distinct energy splitting and magnetic dynamics.