Strong Antiferromagnetic Exchange‐Coupling Observed in Hydride‐Bridged Dimeric Dysprosium(III) Single‐Molecule Magnet

Abstract

Comprehensive SummaryOne dihydride‐bridged dimeric Dy(III) guanidinate complex, formulated as [{(Me3Si)2NC(NiPr)2}2Dy(μ‐H)]2 (1Dy), was successfully isolated and the introduction of hydride bridges significantly reduces the intramolecular Dy(III)···Dy(III) distance to only 3.688(1) Å. To investigate the effect of such a short Dy(III)···Dy(III) distance for magnetism, we also prepared its dibromide‐bridged analogue [{(Me3Si)2NC(NiPr)2}2Dy(μ‐Br)]2 (2Dy), which has a much longer Dy(III)···Dy(III) distance of 4.605(4) Å. Surprisingly, 2Dy demonstrates much larger effective energy barrier for magnetization reversal (Ueff) and higher blocking temperature (TB). The worse performance of 1Dy is attributed to the concerted effect of strong antiferromagnetic interactions between Dy(III) ions (Jtotal = ‐2.683 cm‐1) and the unparallel arrangement of magnetic principle axes of the Dy(III) ions for 1Dy.This article is protected by copyright. All rights reserved.

Effect of Ligands on Quantum Tunneling of Magnetization for Dysprosium C4v Single-Molecule Magnets with Theoretical Insights

“…Both 1 and 2 show butterfly-shaped hysteresis loops with openings up to 6.0 K (Figures S8). The loss of the magnetization at 0 Oe for two compounds indicates the presence of QTM. , …”

“…The loss of the magnetization at 0 Oe for two compounds indicates the presence of QTM. 40,41 To study the SMM behavior of 1 and 2, alternating-current (ac) susceptibility measurements were performed under a zero dc field. The in-phase (χ M ′ ) and out-phase (χ M ″ ) signals of 1 exhibit conspicuous upturning trend with the temperature declining, suggesting SMM behavior existing (Figure S9).…”

Structures and Single-Molecule Magnet Behavior of Dy3 and Dy4 Clusters Constructed by Different Dysprosium(III) Salts

“…Of these, most studies have focused on mononuclear SMMs due to their simplicity as models for probing magneto-structural correlations. 13,14 In the most notable result, Layfield et al synthesized a mononuclear complex which T B broke the limit of liquid nitrogen. 15 Although there have been many developments in mononuclear SMMs, the fast quantum tunneling of magnetization (QTM) process under a zero magnetic field cannot be ignored.…”

“…Therefore, they are favorable candidates for constructing high-performance SMMs. − Usually, the parameters used to evaluate the performance of SMMs are a highly effective energy barrier ( U eff ) and blocking temperature ( T B ). − In the last 20 years, researchers have synthesized many complexes with different nuclear numbers: mononuclear, binuclear, tetranuclear, and hexanuclear. Of these, most studies have focused on mononuclear SMMs due to their simplicity as models for probing magneto-structural correlations. , In the most notable result, Layfield et al synthesized a mononuclear complex which T B broke the limit of liquid nitrogen . Although there have been many developments in mononuclear SMMs, the fast quantum tunneling of magnetization (QTM) process under a zero magnetic field cannot be ignored.…”