Structural, spectral and magnetic properties of carboxylato cobalt(II) complexes with heterocyclic N-donor ligands: Reconstruction of magnetic parameters from electronic spectra

► Carboxylato cobalt(II) complexes with fused N-heterocycles were studied. ► Large zero-field splitting D-parameters were detected (up to 103 cm−1). ► Magnetic parameters were reconstructed from spectral data. ► Usefulness of the crystal-field ZFS models for Co(II) complexes was confirmed.