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

摘要

Static and dynamic magnetic properties of the tetracoordinate Co^II 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.