Tetranuclear [Cu₃Ln] complexes derived from a tetraketone-type ligand

Area of Science:

• Coordination Chemistry
• Magnetochemistry
• Materials Science

Background:

• Lanthanide-transition metal complexes are crucial for developing molecular magnetic materials.
• Designing polynuclear complexes with specific magnetic properties requires careful control over ligand design and metal ion selection.

Purpose of the Study:

• To synthesize and characterize novel tetranuclear copper-lanthanide complexes.
• To investigate the magnetic properties, including magnetic entropy change and magnetic relaxation, of these complexes.

Main Methods:

• One-pot synthesis of tetranuclear [Cu3Ln] complexes using a tetraketone ligand.
• X-ray structural analysis to determine the core structure.
• Cryomagnetic studies to probe magnetic interactions and properties.

Main Results:

• Synthesized three tetranuclear [Cu3Ln] complexes (Ln = Gd, Tb, Dy) with a planar core structure.
• Observed intramolecular ferromagnetic interactions between Cu(II) and Ln(III) ions.
• The [Cu3Gd] complex exhibited a significant magnetocaloric effect (16.4 J kg-1 K-1 at 5 T, 2.4 K).
• The [Cu3Tb] and [Cu3Dy] complexes displayed slow magnetic relaxation, with effective energy barriers of 13.1 K and 6.82 K, respectively.

Conclusions:

• The synthesized complexes demonstrate tunable magnetic properties based on the lanthanide ion.
• The [Cu3Gd] complex shows promise for magnetic refrigeration applications.
• The [Cu3Tb] and [Cu3Dy] complexes exhibit characteristics of single-molecule magnets, paving the way for future research in molecular magnetism.