Dysprosium-based complexes with a flat pentadentate donor: a magnetic and ab initio study.

Area of Science:

• Coordination Chemistry
• Lanthanide Chemistry
• Materials Science

Background:

• Schiff base ligands are versatile in coordinating metal ions.
• Lanthanide complexes are of interest for their magnetic properties.

Purpose of the Study:

• To investigate the reactivity of a pentadentate N3O2 Schiff base (H2L) with dysprosium(III) ions.
• To characterize the resulting dysprosium complexes and explore their magnetic behavior.

Main Methods:

• Synthesis and isolation of dysprosium-Schiff base complexes.
• Single crystal X-ray diffraction for structural determination.
• Dynamic magnetic susceptibility measurements.
• Ab initio CASSCF calculations.

Main Results:

• Two distinct dysprosium complexes, [Dy(HL)(NO3)2]·H2O and [Dy(L)(NO3)(EtOH)(H2O)]·2H2O, were synthesized, with structures dependent on pH.
• A novel hemiacetal donor ligand (H2L') and its dysprosium complex were formed via methanol addition.
• Complexes 2 and 3 displayed field-induced slow relaxation of magnetization, indicating single-molecule magnet behavior.
• Diluted dysprosium-yttrium sample 4 also showed single-molecule magnet properties.

Conclusions:

• The pH of the reaction medium significantly influences the coordination mode and structure of dysprosium-Schiff base complexes.
• The observed reactivity, including hemiacetal formation, is novel for lanthanoid metals.
• Dysprosium complexes derived from H2L can exhibit single-molecule magnet behavior, with energy barriers influenced by factors beyond simple axiality.