Easy-axis magnetic anisotropy in tetragonally elongated cobalt(II) complexes beyond the spin-Hamiltonian formalism

0580108 - FZÚ 2024 RIV GB eng J - Journal Article
Míčová, R. - Rajnák, C. - Titiš, J. - Bieńko, A. - Moncol, J. - Samoľová, Erika - Boča, R.
Easy-axis magnetic anisotropy in tetragonally elongated cobalt(II) complexes beyond the spin-Hamiltonian formalism.
Dalton Transactions. Roč. 52, č. 23 (2023), s. 7885-7892. ISSN 1477-9226. E-ISSN 1477-9234
Institutional support: RVO:68378271
Keywords : Co(II) complexes * crystal-structures * X-ray diffraction * magnetic anisotropy
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Impact factor: 4, year: 2022
Method of publishing: Limited access
https://doi.org/10.1039/d3dt00990d

Two hexacoordinate Co(II) complexes [Co(hfac)2(etpy)2] (1) and [Co(hfac)2(bzpyCl)2] (2) were synthesized and spectrally and structurally characterized. The {CoO4N2} chromophore adopts a geometry of the elongated tetragonal bipyramid with a small o-rhombic component. This less common arrangement causes the magnetic data to need be analysed using the Griffith-Figgis model, instead of the commonly used spin-Hamiltonian with zero-field splitting parameters D and E. In the case of the elongated bipyramid for d7 complexes, the source of the magnetic anisotropy of an easy-axis type is the axial crystal field splitting Δax. The ab initio CASSCF calculations followed by the NEVPT2 module confirm that the ground electronic term is quasi-degenerate owing to the splitting of the 4Eg (D4h) mother term.
Permanent Link: https://hdl.handle.net/11104/0349080