Synthesis and characterization of two new N4O2 macroacyclic Schiff-base ligands containing piperazine moiety and mononuclear Co(III) and Cu(II) complexes, spectral, X-ray crystal structural, theoretical studies, cytotoxic and antibacterial properties

Abstract

Two new Schiff base ligands, H2L1 and H2L2, have been prepared from the condensation of 2-hydroxybenzaldehyde or 2-hydroxy-3-methoxybenzaldehyde with 2,2′-(piperazine-1,4-diylbis (methylene))dianiline (A1), respectively. In the presence of appropriate metal ions and in methanolic/ethanolic solution four Cobalt(III) and Copper(II) macroacyclic Schiff-base complexes were prepared. All resultant products were characterized by elemental analysis, mass spectrometry and spectroscopic methods such as: FT-IR, 1H and 13C NMR. In addition the crystal structures of [CoL1](ClO4) and [CoL2](ClO4)(CH3CN) complexes have been revealed by single-crystal X-ray crystallography. The cytotoxic and antibacterial properties of some of complexes were studied. The geometries of the [CoL1]+ and [CoL2]+ complexes have been optimized at the BP86/def2-SVP level of theory. Also the nature of the metal–ligand bond in the complexes is analyzed with NBO and EDA analysis. Results confirm that the nature of metal–ligand bond in the complexes is slightly more covalent with a contribution of about 53% in total interaction energies.