Magnetic Anisotropy and Field‐induced Slow  Relaxation of Magnetization in Tetracoordinate   CoII Compound [Co(CH3‐im)2Cl2]

Abstract

Static and dynamic magnetic properties of the tetracoordinate CoII complex [Co(CH3‐im)2Cl2], (1, CH3‐im = N‐methyl‐imidazole), studied using thorough analyses of magnetometry, and High‐Frequency and ‐Field EPR (HFEPR) measurements, are reported. The study was supported by ab initio complete active space self‐consistent field (CASSCF) calculations. It has been revealed that 1 possesses a large magnetic anisotropy with a large rhombicity (magnetometry: D = −13.5 cm−1, E/D = 0.33; HFEPR: D = −14.5(1) cm−1, E/D = 0.16(1)). These experimental results agree well with the theoretical calculations (D = −11.2 cm−1, E/D = 0.18). Furthermore, it has been revealed that 1 behaves as a field‐induced single‐ion magnet with a relatively large spin‐reversal barrier (Ueff = 33.5 K). The influence of the Cl–Co–Cl angle on magnetic anisotropy parameters was evaluated using the CASSCF calculations.

Keywords

• slow‐relaxation of magnetization
•  tetracoordinate CoII
•  single ion magnet
•  magnetic  anisotropy