Estructura y propiedades magnéticas de polímeros de coordinación de Mn, Co y Cu basados en ligantes trans, trans-muconato y derivados de 2,2’-bipiridinas

Abstract

In the present work the coordination polymers [Mn(muco)(5,5´-dmbp) (OH2)]n (1); [Cu(OH2) (4,4-dmbp) (muco)]n·2H2O (3); [Cu(OH2)(5,5´-dmbp)(muco)]n·2H2O (4), where (muco) is the bridging ligand trans, trans-muconic acid (H2MUCO) and ancilary ligands derivatives of bipyridines 4,4´-dimethyl-2,2´-bipyridine (4,4´-dmbp) and 5,5´-dimethyl-2,2´-bipyridine (5,5´-dmbp), were synthetized. In addition, a coordination complex [Co2(OH2)4(5,5´-dmbp)2(μ-muco)]muco·MeOH (2) was also obtained. The above mentioned complexes were obtained through self-assembly reactions, carried out in aqueous solution and under ambient conditions. The compounds formed were structurally characterized by single crystal X-ray diffraction, which revealed that compounds 1, 3, and 4 are 1D polymers, which by hydrogen-bonding interactions are expanded in the solid state to 2D supramolecular structures. Similarly, 2 exhibits a supramolecular 2D structure, due to hydrogen bonds. Compounds 1 and 2 have distorted trigonal prismatic central ion geometries, while 3 and 4 have square base pyramid geometry in their central ion. In addition, the magnetic properties of these systems were determined and analyzed, relating them to the structure obtained in each compound. It was found that all compounds have weak antiferromagnetic couplings.