Slow Magnetic Relaxation in Octahedral Cobalt(II) Field-Induced Single-Ion Magnet with Positive Axial and Large Rhombic Anisotropy

Pseudooctahedral mononuclear cobat­(II) complex [Co­(abpt)₂(tcm)₂] (<b>1</b>), where abpt = 4-amino-3,5-bis­(2-pyridyl)-1,2,4-triazole and tcm = tricyanomethanide anion, shows field-induced slow relaxation of magnetization with <i>U</i> = 86.2 K and large axial and rhombic single-ion zero-field-splitting parameters, <i>D</i> = +48(2) cm^–1 and <i>E</i>/<i>D</i> = 0.27(2) (<i>D</i> = +53.7 cm^–1 and <i>E</i>/<i>D</i> = 0.29 from ab initio CASSCF/NEVPT2 calculations), thus presenting a new example of a field-induced single-ion magnet with transversal magnetic anisotropy