Quantum chemical modeling of the mechanism of formation of bis-ligand Co(II) complexes based on polydentate heterocyclic azomethine derivatives: Competition between four-, five-, and six-coordination

Abstract

The molecular structures and relative energies of four-, five-, and six-coordinate stereoisomers of bis-ligand Co(II) complexes based on polydentate heterocyclic azomethine derivatives (CoN₂O₂, CoN₂O₂Y, and CoN₂O₂Y₂ coordination units of the isomers (Y = S, Se)) were calculated using density functional theory. In terms of the proposed quantum chemical model for the mechanism of CoL₂ complex formation, the fivecoordinate structure of complexes with non-equivalent ligands, one being tridentate and the other being bidentate is most probable; this result is in line with experimental data.