Magnetic Coupling in the Ce(III) Dimer Ce-2(COT)(3) - Archive ouverte HAL Access content directly
Journal Articles Inorganic Chemistry Year : 2019

Magnetic Coupling in the Ce(III) Dimer Ce-2(COT)(3)


The monomer [Ce(COT)] and the dimer [Ce(COT)], with Ce(III) and COT = 1,3,5,7-cyclooctatetraenide, are studied by quantum chemistry calculations. Due to the large spin-orbit coupling, the ground state of the monomer is a strong mixing of σ and π states. The experimental isotropic coupling in the dimer was evaluated by Walter et al. to be J = -7 cm (with a Heisenberg Hamiltonian [Formula: see text]) with a small anisotropic coupling of 0.02 cm. The coupling between the two Ce(III) in the dimer is calculated using CI methods. The low energy part of the spectra are modeled by spin Hamiltonians. All spin Hamiltonians parameters are deduced from ab initio calculations. g factors are calculated for both the pseudodoublet of the monomer and the pseudotriplet of the dimer and their sign have been determined. The magnetic coupling in the dimer is rationalized by a model based on crystal field theory. The kinetic and exchange contributions arising from the different configurations to the isotropic and anisotropic couplings are evaluated. It is shown that the main contribution to isotropic coupling is kinetic and originates from the f-f interaction due to the large transfer integral between those orbitals. However, the f-f interaction plays a non-negligible role. The anisotropic coupling originates from the difference of exchange energy of states arising from the ff configuration and is, in no matter, related to the anisotropy of the local magnetic moments as already pointed by van Vleck for a fictitious s-p system. The analysis of the natural orbitals evidences a superexchange mechanism through a σ orbital of the bridging cycle favored by a local 4f/5d hybridization and that the δ type orbitals, both the HOMOs of the ligands and the virtual f orbitals of the cerium atoms play an important polarization role, and to a less extend the π type orbitals, the HOMOs-1 of the ligands, and the metal f orbitals.
Fichier principal
Vignette du fichier
art_cerocene_qua (1).pdf (1.99 Mo) Télécharger le fichier

Dates and versions

hal-01997978 , version 1 (02-12-2020)



Frédéric Gendron, Jochen Autschbach, Jean-Paul Malrieu, Hélène Bolvin. Magnetic Coupling in the Ce(III) Dimer Ce-2(COT)(3). Inorganic Chemistry, 2019, 58 (1), pp.581-593. ⟨10.1021/acs.inorgchem.8b02771⟩. ⟨hal-01997978⟩
77 View
159 Download



Gmail Facebook Twitter LinkedIn More