title: The dilemma of CrIIINiII exchange interactions: ferromagnetism versus antiferromagnetism.
abstract: The sign of the exchange interaction in dinuclear Cr(III)Ni(II) complexes was analyzed using theoretical methods based on density functional theory. This approach allowed us to reproduce the experimental J values correctly. In addition, the Kahn-Briat model, which uses the square of the sum of the overlaps between the magnetic orbitals to correlate with the exchange coupling constant, provided a reasonable correlation between the different types of Cr(III)Ni(II) complexes when using biorthogonalized orbitals. We also examined the exchange interactions in two polynuclear Cr(III)Ni(II) complexes: a Cr(7)Ni ring and an S-shaped Cr(12)Ni(3) complex. We concluded that both systems exhibit antiferromagentic interactions, and that the Cr(III)···Ni(II) interactions are similar in value to the C(III)···Cr(III) exchange couplings.
authors.affiliation: Departament de Química Inorgànica and Institut de Recerca de Química Teòrica i Computacional, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Daniel
authors.initials: D
authors.lastname: Aravena
authors.forename: Eliseo
authors.initials: E
authors.lastname: Ruiz