Tuning spin dynamics of binuclear Dy complexes using different nitroxide biradical derivatives

Area of Science:

• Coordination Chemistry
• Materials Science
• Magnetochemistry

Background:

• Lanthanide-based molecular magnets are of interest for potential applications in data storage and quantum computing.
• Tuning the molecular structure of lanthanide complexes is crucial for controlling their magnetic properties, particularly magnetic relaxation dynamics.
• Nitronyl/imino nitroxide biradicals offer a versatile platform for constructing polynuclear lanthanide complexes with complex spin arrangements.

Purpose of the Study:

• To synthesize and characterize novel lanthanide-zinc complexes using specific nitronyl/imino nitroxide biradicals.
• To investigate the magnetic relaxation behaviors of these tetranuclear complexes, focusing on the influence of ligand structure.
• To establish structure-property relationships governing the spin dynamics in these molecular magnetic materials.

Main Methods:

• Synthesis of three tetranuclear lanthanide-zinc complexes: [Ln2Zn2(hfac)10(ImPhPyobis)2] (Ln = Gd, Dy) and [Dy2Zn2(hfac)10(NITPhPyobis)2].
• Structural characterization involving X-ray crystallography to determine the {Ln2O2} cores and centrosymmetric six-spin structures.
• Magnetic studies, including spin dynamics and magnetic relaxation measurements at zero dc field, to analyze relaxation behaviors.

Main Results:

• Successful preparation of three Ln-Zn complexes with {Ln2O2} cores and tetranuclear six-spin structures.
• Complex 2 (Dy-based) exhibits single-molecule magnet behavior with a single relaxation process (Ueff = 69.8 K).
• Complex 3 (Dy-based) displays double relaxation processes (Ueff = 15.8 K and 50.9 K), attributed to distinct nitroxide biradical derivatives.

Conclusions:

• The distinct magnetic relaxation behaviors in the two Dy complexes are primarily influenced by the structural variations in the nitroxide biradical ligands.
• These findings highlight the importance of ligand design in tailoring the magnetic properties of lanthanide-based molecular materials.
• The synthesized complexes serve as promising candidates for developing advanced molecular magnetic materials with controllable spin dynamics.