Field Induced Single Ion Magnetic Behaviour in Square-Pyramidal Cobalt(II) Complexes with Easy-Plane Magnetic Anisotropy

• Main Authors: Amit Kumar Mondal, Arpan Mondal, Sanjit Konar
• Format: Article
• Language: English
• Published: MDPI AG 2019-02-01
• Series: Magnetochemistry
• Subjects: Cobalt(II); square-pyramidal; single ion anisotropy; slow magnetic relaxation
• Online Access: https://www.mdpi.com/2312-7481/5/1/12

Two penta-coordinate Co^II complexes with formulae [Co(14-TMC)Cl](BF₄) (<b>1</b>, 14-TMC = 1,4,8,11-Tetramethyl-1,4,8,11-tetraazacyclotetradecane) and [Co(12-TBC)Cl](ClO₄)&#183;(MeCN) (<b>2</b>, 12-TBC = 1,4,7,10-Tetrabenzyl-1,4,7,10-tetraazacyclododecane) were synthesized and characterized. Structural analysis revealed that ligand coordinates to the Co^II centre in a tetradentate fashion and the fifth position is occupied by chloride ion and the geometries around Co^II centres are best described as distorted square pyramidal. Detailed magnetic measurements disclose the presence of significant easy-plane magnetic anisotropy and field induced slow magnetic relaxation behaviours of the studied complexes. More insight into the magnetic anisotropy has been given using <i>ab initio</i> theory calculations, which agree well with the experimental values and further confirmed the easy-plane magnetic anisotropy.