DFT study of magnetic coupling in bis(pyridine-2-carboxylate)-copper(II) polymorphs

The method for exchange coupling parameter J calculations using a broken-symmetry treatment is extended to three-dimensional periodic DFT calculations for three antiferromagnetic polymorphic forms of Cu(pca)2, pca = pyridine-2-carboxylate. The calculated values (<1 cm−1) are slightly underestimated in comparison with experimental data. For comparison with the cluster treatment, the J values are rationalized using the nearest-neighbors model for polymeric chains.