Synthesis, spectral characterization, antimicrobial evaluation and molecular docking studies on new metal complexes of novel Schiff base derived from 4,6-dihydroxy-1,3-phenylenediethanone

Abstract

A new tetradentate Schiff base ligand was prepared from condensation of 4,6-dihydroxy-1,3-phenylenediethanone with ethane-1,2-diylbis(oxy)diethanamine. The ligand forms complexes in good yield. The Schiff base and its complexes were characterized by analytical (CHN elemental analyses, solubility, melting point, conductivity) measurements, spectral (IR, UV–vis, 1H NMR and MS) and magnetic measurements. The elemental analyses, Uv-vis spectra, and room temperature magnetic moment data and theoretically through density function theory were used as characterization techniques in supporting of further interpretation of the complexes structures. The results of elemental analyses, EI-mass and conductivity measurements confirmed the stoichiometry of the ligand and its complexes while the characteristic absorption bands and resonance peaks in IR and NMR spectra confirmed the formation of the ligand frameworks around the metal ions. The octahedral environment for complexes derived from Schiff base ligand have been confirmed based on results of electronic and diffused reflectance spectral studies and magnetic moment measurements. Detailed studies on the thermal properties of the Schiff base ligand and complexes were investigated by thermogravimetric technique. Moreover, the molecular docking into (PDB: 6NE0) was the DNA binding and supports the experimental finding and 6IY0 crystal structure of conserved hypothetical protein SAV0927 from Staphylococcus aureus subsp. aureus Mu50. The synthesized ligand and its complexes were tested for in vitro antimicrobial activity against Candida albicans, Aspergillus flavus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus by using agar-well diffusion method. An enhancement in the antimicrobial activity due to metal chelation was observed.