Synthesis of metal(II) acetate complexes with a heterocyclic azo dye ligand: Characterization, geometrical molecular structures, antioxidant, biological activities, DNA binding and molecular docking studies

Abstract

A series of Cu(II), Co(II), Ni(II), Mn(II), and UO2(II) complexes have been prepared from the ligand 4-(2’,4’-dihydroxybenzaldehyde phenylazo)antipyrine (H2L). FT-IR spectra demonstrated that the ligand under investigation behaves as a bi-and tridentate centre ligand through the phenolic oxygen of aldehydic, azo nitrogen atoms and carbonyl oxygen of antipyrine and forms a stable five- and six-membered chelating ring. From the X-ray crystallographic analysis (XRD) patterns of the ligand and complexes showed the polycrystalline phases are indicated by the multiple diffraction peaks in the 1igand and its complex (5). The HOMO‒LUMO energy gaps (∆E) were used to create theoretical models for the structure and confirmation barriers in molecular systems for the ligand (H2L) and metal complexes. It was found that the Cu(II), Co(II), Ni(II), and Mn(II) complexes have lower values for HOMO‒LUMO energy gaps (∆E), indicating that they are more stable than the 1igand. The biological activities of ligand (H2L) and its metal complexes showed that ligand was stronger antimicrobial and antioxidant agent than its metal complexes. 50 µg/ml H2L caused inhibition zones ranged from 13 to 20 mm against the tested bacteria and 13 to 16 against fungi. In addition, the present study tested metal (II) acetate complexes with a heterocyclic azodye ligand for their application in the textile industry as antimicrobial dyed fabrics. All obtained results confirmed the possibility of using the prepared compounds in different industrial applications. The 1igand (H2L) and its metal complexes showed moderate to strong antimicrobial activities in agar well diffusion, MIC, and antioxidant tests. Ligand and its metal complexes revealed inhibition zones against all tested microbes ranged between 6 to 24 mm. The MIC values of ligand and its metal complexes were recorded at 20 to 30 μg/ml and 30 to 145 μg/ml, respectively. 50 µg/ml of 1igand and its metal complexes was enough to complete inhibit Gram negative E. coli moreover they could inhibit the multidrug resistant bacteria K. pneumoniae and Pseudomonas sp. By molecular docking study, it was found that the complex (1) showed the highest and better binding affinity (-8.38874 and -7.74442 kcal/mol) than other 1igand (H2L) and complexes (2–5) for the breast cancer (3HB5) protein central activity and the colon cancer (2HQ6) protein central activity.