Slow Magnetic Relaxation in a [Co₄O₄] Cubane Complex with Tridentate <i>NNO</i>-Schiff Base Ligands

Abstract

Two tetranuclear Co(II) complexes, [Co4(pmab)4Cl4] (1) and [Co4(pmab)4(OBz)2]Cl2 (2) [Hpmab = 2-{(p-pyridinylmethylene)amino}benzenemethanol], have been synthesized and characterized through single-crystal X-ray diffraction, IR and UV-VIS spectroscopy, and magnetic measurements. Structural analysis revealed that both complexes possess a [Co4O4] cubane-like metal core connected by μ3-alkoxo bridges. Magnetic measurements of Complex 1 indicate weak ferromagnetic interactions (J ~ +0.75 cm−1) within the tetranuclear core, while Complex 2 exhibits antiferromagnetic behavior due to the presence of syn-syn bridging benzoate ligands. Alternating current (AC) magnetic measurements suggest that Complex 1 exhibits slow magnetic relaxation behavior.

Keywords

• tetranuclear complex
• cobalt
• crystal structure
• cubane
• Schiff base ligand
• magnetic property