Dianionic or tetraanionic ligand: Synthesis, Hirshfeld surface analysis, DFT, electrochemical and magnetic properties of mono- and dinuclear Cu(II) complexes derived from a deprotonated Schiff base

•A polydentate Schiff base ligand was synthesized and characterized.•The coordination reactions of the ligand with copper(II) acetate were investigated under different molar ratios, and characterized by single-crystal X-ray diffraction.•Hirshfeld surface analysis, DFT, electrochemical and magnetic properties of the two complexes were investigated. The Schiff base condensation reaction of N,N′-bis(2-amiophenyl)-pyridine-2,6-dicarboxamide and 2-hydroxy-3-methoxybenzaldehyde yielded a polydentate ligand (H4L). The coordination reactions of the ligand with copper(II) acetate were investigated under different molar ratios, and the reaction products were characterized by infrared spectroscopy, element analysis, single-crystal X-ray diffraction and powder X-ray diffraction. In the case of a 1:1 molar ratio of ligand H4L and copper(II) acetate, a mononuclear complex [Cu(H2L2−)] (1) was obtained. By contrast, the treatment of ligand H4L with twice copper(II) acetate afforded a dinuclear complex [Cu2(L4−)(CH3OH)(H2O)]‧H2O (2). The different coordination configurations in the two complexes reveal that the ratio of organic ligand and metal ion has remarkable influences on the structural topologies. Furthermore, Hirshfeld surface analysis, DFT, electrochemical and magnetic properties of the two complexes were investigated as well. Two Cu(II) complexes were synthesized in the case of different molar ratios of a Schiff base ligand with copper(II) acetate. A view of the different geometries discloses that the ligand can participate in the coordination reactions through two different deprotonated forms. [Display omitted]