Synthesis, physicochemical elucidation, biological screening and molecular docking studies of a Schiff base and its metal(II) complexes

Abstract

A Schiff base 1-((3-nitrophenylimino)methyl)naphthalen-2-olate (HL) and its two novel complexes with Zn(II) and Co(II) metals were successfully synthesized and characterized by FTIR, 1H NMR, 13C NMR, elemental analysis, magnetic susceptibility, TGA and EIS-MS. Crystal of Schiff base was also characterized by X-ray analysis and experimental parameters were found in line with the theoretical parameters. Quantum mechanical approach was also used to compare structural and calculated parameters and to ensure the geometry of metal complexes. The photometric behaviors of all the synthesized compounds were investigated in a wide pH range using BR buffers. Appearance of isosbestic point suggested the existence of Schiff base molecules in different tautomeric forms. Binding of synthesized complexes with calf thymus DNA was explored by photometric and voltammetric titrations and binding constants were calculated. The results indicated that ligand and its metal complexes bind to DNA by intercalation mode. Docking studies indicate their binding possibilities with topoisomerase II. Moreover, all these prepared compounds were screened for enzyme inhibition, antibacterial, cytotoxic and in vivo antidiabetic activities and found active against one or other activity. This effort just provides preliminary data for some biological properties and which can act as foundation stone for their application in drug development. Keywords: Schiff base-metal complexes, Spectroscopy, X-ray analysis, DNA binding, Molecular docking