Dy(BC₄Ph₅)(C₅ⁱPr₅): A Heteroleptic Sandwich Complex with Strong Axiality Giving Rise to Magnetic Blocking at 65 K

Area of Science:

• Materials Science
• Inorganic Chemistry
• Quantum Magnetism

Background:

• Mononuclear single-molecule magnets (SMMs) are crucial for advancing quantum computing and data storage.
• Dysprosium (Dy) complexes with sterically encumbered cyclic ligands show potential as high-performance SMMs.
• Tuning ligand environments is key to optimizing SMM properties like blocking temperature and relaxation barriers.

Purpose of the Study:

• To synthesize and characterize a novel heteroleptic dysprosium sandwich complex, Dy(BC4Ph5)(C5iPr5).
• To investigate the impact of combining borolide and cyclopentadienide ligands on SMM behavior.
• To understand the structure-property relationships governing high-temperature magnetism in these systems.

Main Methods:

• Synthesis of the heteroleptic dysprosium complex Dy(BC4Ph5)(C5iPr5).
• Single-crystal X-ray diffraction for structural analysis.
• Magnetic property measurements to determine relaxation barrier (Ueff) and blocking temperature (Tb).
• Computational analyses, including density functional theory (DFT), to probe electronic structure and ligand interactions.

Main Results:

• The synthesized complex Dy(BC4Ph5)(C5iPr5) exhibits high-temperature SMM behavior with Ueff = 1536(15) cm⁻¹ and Tb = 65 K.
• Structural analysis revealed reduced ligand-ligand repulsion compared to bis(borolide) analogs.
• Computational studies indicated a weaker axial field from the cyclopentadienide ligand.
• Performance was superior to related bis(cyclopentadienide) complexes but comparable to bis(borolide) complexes.

Conclusions:

• The heteroleptic complex Dy(BC4Ph5)(C5iPr5) demonstrates high-temperature magnetic performance, approaching that of state-of-the-art SMMs.
• Ligand design, balancing axial field strength and ligand-ligand repulsion, is critical for optimizing SMM properties.
• Heteroleptic dysprosium complexes offer a tunable platform for developing next-generation high-temperature single-molecule magnets.