Possibilities of tetra-, penta-, and hexacoordination in quantum-chemical simulation of mechanism of formation and stereoisomerization of bisligand azomethine complexes of Zn(II), Cd(II), and Hg(II)

The competition between tetra-, penta-, and hexacoordination with the MN₂O₂, MN₂O₂X, and MN₂O₂X₂ (X = S, Se) coordination nodes, respectively, during the formation of bisligand Zn(II), Cd(II), and Hg(II) complexes with bi- and tridentate heterocyclic azomethines has been studied by means of quantumchemical DFT simulation of the complex formation and further stereoisomerization. It has been found that pentacoordination was favorable for the Cd(II) and Hg(II) complexes, whereas the Zn(II) complexes are tetracoordinate.