Engineering macrocyclic high performance pentagonal bipyramidal Dy(iii) single-ion magnets.

Area of Science:

• Coordination Chemistry
• Materials Science
• Magnetism

Background:

• Single-molecule magnets (SMMs) are molecular materials exhibiting slow magnetic relaxation.
• Developing air-stable SMMs with high blocking temperatures is crucial for practical applications.
• Lanthanide ions, such as Dy(iii), are promising building blocks for high-performance SMMs.

Purpose of the Study:

• To synthesize a novel air-stable dysprosium(iii) single-molecule magnet.
• To investigate the impact of ligand field geometry on magnetic anisotropy.
• To explore the potential of macrocyclic ligand engineering for tuning SMM properties.

Main Methods:

• Synthesis of a dysprosium(iii) complex featuring a macrocyclic L^N5 ligand.
• Magnetic property measurements, including direct current (DC) and alternating current (AC) susceptibility.
• Ab initio calculations (CASSCF/S T-2) to elucidate the electronic structure and magnetic anisotropy.

Main Results:

• A new air-stable pseudo-D5h Dy(iii) complex was successfully synthesized.
• The complex exhibits slow magnetic relaxation, characteristic of SMM behavior, with Ueff = 1108 K and Tb = 14 K.
• Ab initio calculations confirmed the weak equatorial and strong axial ligand fields, correlating with the observed magnetic anisotropy.

Conclusions:

• The combination of a macrocyclic ligand and strong axial field creates an effective environment for SMM behavior in Dy(iii).
• Macrocyclic ligand engineering presents a versatile strategy for designing and optimizing magnetic anisotropy in lanthanide-based SMMs.
• This work provides a synthetic blueprint for future development of high-performance, air-stable single-molecule magnets.