A fluorobenzene-bound dysprosium half-sandwich dication single-molecule magnet

Area of Science:

• Inorganic Chemistry
• Materials Science
• Quantum Computing

Background:

• Dysprosium single-molecule magnets (SMMs) with dual anionic ligands offer high energy barriers but suffer from bent structures that compromise magnetic performance.
• Bent geometries in SMMs lead to impure crystal field states and increased magnetic relaxation, limiting their potential applications.
• A single charge-dense anionic ligand approach could yield purer crystal field states and improved SMM properties.

Purpose of the Study:

• To synthesize and characterize a novel half-sandwich dysprosium(III) complex with a single anionic ligand for enhanced SMM performance.
• To investigate the impact of this unique topology on crystal field splitting, magnetic reversal barriers, and blocking temperatures.
• To explore synthetic methodologies for creating high-performance axial dysprosium SMMs.

Main Methods:

• Synthesis of a half-sandwich Dy(III) complex, [Dy(Cp*)(FPh)₆][{Al[OC(CF₃)₃]₃}₂(μ-F)]₂ (1-Dy), and its Y(III) analogue.
• Characterization of magnetic properties, including effective energy barriers (U_eff) and hysteresis temperatures (T_H).
• Salt metathesis reactions to assess ligand lability and explore alternative complex formations.

Main Results:

• The synthesized complex 1-Dy demonstrated a high effective energy barrier (U_eff) of 545(30) cm^-1 and a hysteresis temperature (T_H) of 14 K.
• The Cp* ligand and a single axial fluorobenzene ligand created a strong axial crystal field, minimizing transverse interactions.
• The fluorobenzene ligands were found to be easily displaceable, indicating potential for further structural modification.

Conclusions:

• The single anionic ligand topology successfully yields highly pure crystal field states, leading to superior SMM performance.
• This approach offers a promising route to developing next-generation dysprosium SMMs with enhanced magnetic stability and operating temperatures.
• The synthetic strategies employed can be adapted for designing advanced axial dysprosium SMMs with tailored ligand environments.