Homochiral Ferromagnetic Coupling Dy₂ Single-Molecule Magnets with Strong Magneto-Optical Faraday Effects at Room Temperature

Abstract

By the bridging action of the 6-chloro-2-hydroxypyridine (Hchp) ligand and the terminal coordination role of the homochiral ligand, (−)/(+)-3-trifluoroacetyl camphor (l-Htfc/d-Htfc), a pair of enantiomerically pure dysprosium­(III) dinuclear complexes, [Dy2(l-tfc)4(chp)2(MeOH)2] (l-1) and [Dy2(d-tfc)4(chp)2(MeOH)2] (d-1), was obtained. Their circular dichroism (CD) spectra verified their enantiomeric nature. Magnetic investigation indicated that they exhibit ferromagnetic interaction and good zero field single-molecule magnet (SMM) properties. The U eff/k values of l-1 and d-1 at 0 Oe are 180.5 and 181.3 K, respectively, which are large values for homochiral Dy­(III) SMMs. A reasonable explanation for the magnetic properties of l-1 and d-1 was supplied by ab initio calculations. Remarkably, magnetic circular dichroism (MCD) investigation revealed that the chiral Dy2 enantiomers show a strong magneto-optical Faraday effect at room temperature, suggesting potential applications in magneto-optical devices.

Modulating Two Pairs of Chiral DyIII Enantiomers by Distinct β-Diketone Ligands to Show Giant Differences in Single-Ion Magnet Performance and Nonlinear Optical Response

“…Description of the Structures. Single-crystal structure analysis indicated that R-1-Dy/S-1-Dy and R-2-Dy/S-2-Dy belong to homochiral enantiomeric pairs with near-zero Flack parameter values of 0.006(12)/0.008 (9) for R-1-Dy/S-1-Dy and −0.032(16)/0.018 (9) for R-2-Dy/S-2-Dy, and all of them crystallize in noncentrosymmetric monoclinic space group P2 1 . Thus, the structures of R-1-Dy and R-2-Dy as representatives are described in detail.…”

“…Multifunctional coordination compounds (CCs) have been the hot subject of research in the fields of coordination chemistry and materials science, , and the use of homochiral ligands is an effective approach to prepare multifunctional CCs that possess unique physical properties, such as second-harmonic generation (SHG), ferroelectricity, piezoelectricity, and pyroelectricity, which are only related to the lack of an inversion center. − In particular, introducing chirality into magnetic CCs, the resulting chiral CCs may exhibit enchanting magnetochiral dichroism, a magneto-optical Faraday effect, and a magnetoelectric coupling phenomenon, being expected to be able to furnish the original solutions in high-density data storage and quantum computing. − In terms of magnetism, lanthanide ions (Ln III ), especially the Dy III ion, have large spin ground state and magnetic anisotropy, making them suitable for constructing high-performance single-molecule/ion magnets (SMMs/SIMs) that have promising applications in information storage, quantum computing, and molecular spintronics. − Among the reported Dy III SMMs/SIMs, mononuclear species with high D 4 d , D 5 h , D 6 h , C ∞ v , and D ∞ h axial symmetries have been shown to be ideal candidates for exhibiting high-performance SIM behavior. − However, the mononuclear chiral Dy III SIMs among them are rather scarce, − mainly due to the difficulty of controlling chirality in the whole magnetic molecular systems.…”

Asymmetric Assembly of Chiral Lanthanide(III) Tetranuclear Cluster Complexes Using Achiral Mixed Ligands: Single-molecule Magnet Behavior and Magnetic Entropy Change

“…On the other hand, if chirality is introduced into molecular magnets, it will bring valuable physical properties such as nonlinear optics, − ferroelectricity, − and magneto-optical effects, − making them attractive multifunctional molecular materials. The general case is to obtain chiral structured molecule-based magnets by chiral ligand coordination − or even by cocrystallizing with chiral organic molecules .…”

Syntheses, structures, and magnetic properties of acetate-bridged lanthanide complexes based on a tripodal oxygen ligand

“…In high-temperature regions, the χ M T products of 1 , 2 , and 3 decrease slowly and reach the respective minimum values of 23.08 ( 1 , 9.0 K), 11.65 ( 2 , 2.0 K), and 6.81 ( 3 , 2.0 K) cm 3 K mol −1 , usually caused by antiferromagnetic couplings between adjacent lanthanide (III) ions, and/or depopulation of Ln 3+ ions excited Stark (M J ) sublevels ( Lim et al, 2016 ; Liu et al, 2016 ; Li J et al, 2021 ). Upon lowering the temperature to 2.0 K, the χ M T value of 1 rises again to a maximum of 24.40 cm 3 K mol −1 , indicating the existence of weak intramolecular ferromagnetic interactions between the paramagnetic dysprosium (III) centers ( Gao et al, 2019 ; Shen et al, 2020 ; Li X et al, 2021 ; Liu et al, 2021 ). In 4 , the χ M T values are almost unchanged from 300 to 30.0 K and drop eventually to around 2.0 K to 12.64 cm 3 K mol −1 , suggesting the occurrence of antiferromagnetic Gd 3+ ∙∙∙Gd 3+ coupling.…”