Synthesis, characterization, theoretical study and molecular docking studies of some new cobalt(II), chromium(II) and nickel (II) complexes

Abstract

Three transition metal complexes with general formula [M(L)₂] (Co = (1), Cr = (2)  and Ni = (3), were synthesized by treating CoCl₂/CrCl₃.6H₂O/NiCl₂.6H₂O with an ONS-donor Schiff base ligand(HL) derived from the condensation 3,5-Diiodosalicylaldehyde and 4,4-Dimethyl-3-thiosemicarbazide. The geometry around the centre metal ions was octahedral as revealed by the data collection from spectroscopic studies. The newly synthesized compounds were fully characterized by various physicochemical and spectroscopic methods.  DFT calculations were performed on the compounds to get a structure-property relationship. Some global reactivity descriptors like chemical potential (μ), electronegativity (χ), hardness (η) and electrophilicity index (ω) were also evaluated using DFT method. The ADMET prediction analysis have been explored.  Molecular dynamics simulations were also studied. Besides this, to find a potential inhibitor for anti-SARS-CoV-2, metal complexes would also assessed through molecular docking and 3-D visualizations of intermolecular interactions against  main protease (M^pro) of SARS-CoV-2 (PDB ID: 7JKV).The molecular docking calculations of the complex (1) into the main protease of SARS-CoV-2 virus (PDB ID: 7JKV) revealed the binding energy of -7.2 kcal/mol with an inhibition constant of 2.529 µM at inhibition binding site of receptor protein. Complex (2) with SARS-CoV-2 resulted in the binding energy of -7.8 kcal/mol and the inhibition constant of 5.231 µM. Similarly, complex (3) with SARS-CoV-2 (PDB ID: 7JKV) exhibited the binding energy and the inhibition constant of -7.5 kcal/mol and 3.585 µM respectively at inhibition binding site of receptor protein. Overall, in silico studies explored the potential role of metal complexes, which would offer new drug candidates against SARS-CoV-2.