Gusev, A., Baluda, Y., Matiukhina, A., Kiskin, M., & Linert, W. (2024). Coordination number impact on magnetic properties of Schiff base Co(II) complexes. Polyhedron, 259, Article 117074. https://doi.org/10.1016/j.poly.2024.117074
Cobalt(II); Schiff base; Single-ion magnets; 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone; Magnetic anisotropy
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Abstract:
Two mononuclear Co(II) complexes with a tetrahedral and octahedral coordination geometry with a Schiff base ligand L (anion of 4-[(2-fluoroanilino)-phenyl-methylene]-5-methyl-2-phenyl-pyrazol-3-one) having the formulas [CoL2]⋅2MeCN (1) and [CoL2(H2O)2]⋅2MeCN (2) have been synthesized and structurally characterized.
Notably, their coordination geometry and magnetic relaxation behaviors can be tuned by variation of reaction conditions. Static magnetic studies reveal that complex 1 exhibits considerable easy-axis magnetic anisotropy.
Frequency-dependent susceptibility measurements revealed slow magnetic relaxation behavior with spinreversal barriers of 79.2 K at an applied external field of 500 Oe. Clear magnetic hysteresis loops were observed for 1 at 2 K. Complex 2 show field-induced slow magnetic relaxation with Raman and direct relaxation processes. The observed magnetic behavior of 1 and 2 is confirmed by high-level ab initio calculations and simulation of χMT(T) curves.
