Synthesis and characterization of novel heterocyclic diazenyl pyridinone copper(II) complexes with antimicrobial, antioxidant, and anticancer properties

The novel diazenyl pyridinone heterocyclic ligands and their Cu(II) complexes have been prepared and characterized utilizing miscellaneous analytical tools, thermogravimetric analysis (TGA), and nuclear magnetic resonance (NMR), Fourier transform infrared (FTIR), electron paramagnetic resonance (EPR), and ultraviolet-visible spectroscopies. The investigated ligands are coordinated in a bidentate fashion through the azo nitrogen atom and the hydroxyl oxygen atom to the Cu(II) center. The EPR spectra indicated that the obtained complexes were monomeric, and density functional theory (DFT) calculations confirmed that the Cu(II) atom adopted a six-coordinated octahedral geometry. The ligands and their complexes were investigated for their in vitro antimicrobial activity against some types of bacteria and fungi. The antioxidant and anticancer activities of the complexes were also assessed. The results show that these complexes exhibit higher antitumor efficiency and selectivity index against the models of human breast adenocarcinoma cells MCF-7 and human primary hepatocytes THLE-2 than the reference standard material doxorubicin. The results were supported by DFT calculations, molecular docking, and Hirshfeld surface analysis.