Magnetic Hysteresis at 31 K in a Four-Coordinate Dysprosium(III) Amide Complex

Area of Science:

• Materials Science
• Chemistry
• Physics

Background:

• Single-molecule magnets (SMMs) are crucial for advancing molecular magnetism and quantum computing.
• Current SMM design is often dominated by dysprosium complexes with π-ligands, achieving high magnetic hysteresis temperatures.
• Alternative ligand strategies, like charge-dense amides, can increase magnetic reversal barriers but often at the expense of hysteresis temperatures.

Purpose of the Study:

• To report a novel four-coordinate dysprosium(III) SMM, [Dy{Me2Si(NSiiPr3)2}2{K(toluene)2}]n (1Dy), utilizing charge-dense amide donors.
• To investigate the magnetic properties and performance of this new SMM architecture.
• To explore an alternative design strategy for high-performance lanthanide SMMs.

Main Methods:

• Synthesis and characterization of the four-coordinate dysprosium(III) complex (1Dy).
• Magnetic property measurements, including magnetic hysteresis loops and relaxation times.
• Ab initio calculations to determine crystal field effects and spin dynamics.

Main Results:

• 1Dy exhibits open-loop magnetic hysteresis up to 31 K at a sweep rate of 22 Oe s-1.
• The coercive field (Hc) is 1.65 T at 1.8 K, and the 100 s blocking temperature (TB100) is 10.4 K.
• Ab initio calculations reveal a strong axial crystal field (CF) splitting the spin-orbit multiplet by 1958 K (1361 cm-1).

Conclusions:

• The four-coordinate geometry of 1Dy imparts a significant crystal field, leading to high-performance SMM characteristics.
• This alternative design strategy offers a synthetically accessible route to high-performance monometallic lanthanide SMMs.
• 1Dy demonstrates competitive magnetic properties compared to existing lanthanide SMMs, suggesting potential for further refinement.