Elucidation of the Magnetism of [Co2PdCl2(dpa)4]: Origin of a Large Temperature Domain of TIP Behavior

Abstract

The recently synthesized heterotrimetallic complex [Co2PdCl2(dpa)(4)] shows an unusual temperature-independent paramagnetism (TIP), extending over the whole experimental temperature range (0-300 K; Rohmer et al. Angew. Chem., Int. Ed. 2007, 46, 3533). We explain this behavior from a microscopic approach, using ligand-field theory and Anderson's kinetic exchange theory, treating the nonmagnetic Pd-II as a ligand. The orbital degeneracy of the Co-II ions is taken into account in the construction of the model Hamiltonian. The extension of the TIP behavior, compared to that of mononuclear Co-II compounds, over the whole temperature domain, is explained by the quenching of magnetic moments in thermally populated levels by a strong antiferromagnetic exchange interaction.status: publishe