Slow magnetization dynamics in Co(ii)/Co(iii) triethanolamine/pivalate complexes.

Area of Science:

• Coordination Chemistry
• Magnetochemistry
• Quantum Chemistry

Background:

• Cobalt complexes are of interest for their magnetic properties.
• Understanding single-molecule magnet (SMM) behavior is crucial for developing new magnetic materials.

Purpose of the Study:

• To synthesize and characterize novel cobalt complexes.
• To investigate the magnetic properties and SMM behavior of these complexes.
• To elucidate the factors governing the magnetic relaxation processes.

Main Methods:

• Synthesis and structural characterization of mononuclear and tetranuclear cobalt pivalate complexes.
• Experimental magnetic studies including DC and AC susceptibility measurements.
• High-field electron paramagnetic resonance (HF-EPR) spectroscopy.
• Computational studies using CASSCF (Complete Active Space Self-Consistent Field) methods.

Main Results:

• The tetranuclear Co(II)3Co(III) complex displays slow magnetic relaxation (SMM behavior) under an applied DC field.
• An effective magnetic relaxation barrier of approximately 30 cm⁻¹ was determined for the SMM.
• The observed behavior is attributed to anisotropic exchange interactions and well-isolated Kramers doublets arising from strong local zero-field splitting of Co(II) ions.
• Computational and experimental data support the proposed magnetic model.

Conclusions:

• The study successfully synthesized and characterized novel cobalt complexes with distinct magnetic properties.
• The tetranuclear complex demonstrates promising SMM characteristics, with its behavior explained by electronic structure and magnetic interactions.
• Combined experimental and computational approaches provide a comprehensive understanding of the magnetic phenomena in these cobalt systems.