Magnetic Analysis of Two [Cobalt-Imidazole-Carboxylate] Complexes: Orbital Contribution

Abstract

Two coordination complexes, Co(HIMC) 2 (H 2 O) 2 (1) and Co(H 2 IMDC) 2 (H 2 O) 2 (2), were synthesized by mixing the complex precursor Cobalt(II) hexafluoroacetylacetonate (Co(hfacac) 2 ) with 1H-imidazole-4-carboxylic acid (H 2 IMC) and 1H-imidazole-4,5-imidazoledicarboxylic acid (H 3 IMDC) ligands.These compounds have been isolated as neutral, air and thermal stable solid and have been characterized by FT-IR and powder X-Ray diffraction analysis. The thermal stability and magnetic properties were studied in the solid state.Compounds (1) and (2) are mononuclear complexes, where the cobalt ions adopt an distorted octahedral geometry. At low temperature they exhibit a weak antiferromagnetic interaction. The contribution of the angular momentum to the magnetic moment as well as intermolecular interactions were taken into consideration for the quantitative modeling of their magnetic properties