Ab initio study of the magnetic coupling in oxalato-bridged dinuclear Ni(II) complexes

The magnetic coupling has been studied in various oxalato bridged dinuclear Ni(II) complexes with accurate ab initio computational schemes. We assess the dependence of the magnetic coupling between the two Ni(II) centers on the electronegativity of the atoms in the coordination sphere of the magnetic centers and on the distance between the Ni and the oxalato bridge. It is found that both have comparable effects. Furthermore, a study has been performed to establish the influence on the magnetic coupling of the counterion, the modelization of the external ligands and the symmetrization of the geometry. All three terms are found to have a very small effect on the calculated magnetic coupling strengths.