Novel Schiff Bases Ligands and Their Complexes: Thermal Analysis, Antibacterial Activity, and Molecular Docking

Abstract

The transition metal complexes of novel tetradentate-ketoenamine ligands were synthesised by condensing β-diketone (acetylacetone, 3-chloro acetylacetone) with 4,4'-methylenedianiline. Fourier-transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance ( 1 H NMR) spectroscopy, carbon-13 NMR ( 13 C NMR) spectroscopy, electron ionisation mass spectrometry (EIMS), elemental analysis, and UV-visible (UV-Vis) spectroscopy were used to describe the compounds while thermogravimetric (TG/DTG) analysis was used to investigate the thermal breakdown of the complexes. All of the complexes showed outstanding stability as well as different degrees of thermal decomposition. Antibacterial activity was tested using gram-positive (Bacillus subtilis, Staphylococcus aureus) and gram-negative (Bacillus subtilis, Staphylococcus aureus) bacteria (Escherichia coli, Salmonella typhi). Minimal inhibitory concentrations (MICs) of 0.5 to 2 mM/ml and minimum bacterial concentrations (MBCs) of 2 to 4 mM/ml were used in this study. A molecular docking study was also conducted to ensure that the compounds connected well to the active sites of the target enzymes; such as topoisomerase II DNA gyrase enzymes (2XCT) and methicillin-resistant Staphylococcus aureus (MRSA,2x3f.pdb).