Metal Complexes of Tridentate Schiff Base: Synthesis, Characterization, Biological Activity and Molecular Docking Studies with COVID-19 Protein Receptor

Abstract

Mononuclear chelates of Cr(III), Mn(II), Fe(III), Ni(II), Cu(II), Zn(II) and Cd(II) resulting from new tridentate Schiff base ligand, 4-((1-(5-acetyl-2,4-dihydroxyphenyl)ethylidene)amino)-1,5-dimethyl-2-phenyl-1H-pyrazol-3(2H)-one, were synthesized and characterized via various spectroscopic methods. Metal to ligand ratio was found to be 1:1, which was revealed via elemental analysis. IR has sharp out that the coordination of the ligand towards the metal ions was carried out via NOO atoms. UV-Vis, 1HNMR spectral data, molar conductance measurements, BET surface area, melting points and theoretically through density function theory were used such as characterizing techniques in supporting of further interpretation of the complexes structures. The complexes were octahedral except Cu(II) and Ni(II) complexes were tetrahedral as suggested through the magnetic moment measurement. The complexes were found to have surface area, pore volume and particle radius 23–176 m2 g− 1, 0.02–0.33 cc/g and 8.71–4.32 nm, respectively, as pointed out from BET measurement. Schiff base ligand and its metal complexes were tested in vitro to estimate their bactericidal activity opposed to Gram-negative and Gram-positive bacteria and antifungal organisms. In the recent incident of a novel coronavirus (SARS-CoV-2) spreads, antiviral drug detection is of most importance. MOE 2008 was used headed for screen potential drugs with molecular docking by the structural protein and non-structural protein sites of new coronavirus and the study was constructed to molecular docking without validation through MD simulations. Interactions with the main protease may play a key role in fighting against viruses.