Synthesis, theoretical study, molecular docking and biological activity of nano tridentate (E)-2-((3-hydoxyphenyl)methyl)phenol metal complexes

A new series of transition metal complexes of Schiff base (E)-2-((3-hydoxyphenyl)methyl)phenol (H2L) with Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) have been synthesized and characterized using elemental analysis, IR, UV–Vis spectra, mass spectra, reflectance spectra, molar conductance measurements, magnetic susceptibility measurements, 1H NMR spectroscopy, thermal and X-ray diffraction analyses. The infrared spectral data showed that the chelation of the ligand towards transition metal ions occurs through two deprotonated phenolic oxygen atoms and azomethine nitrogen (ONO) in binegative tridentate manner. The XRD patterns of the complexes have sharp diffraction peaks indicating that these complexes are a mixture of crystalline and amorphous phases. The molecular structures of the Schiff base ligand and its metal complexes were optimized theoretically and the quantum chemical parameters were calculated. Molecular docking was used to predict the efficiency of binding between the Schiff base ligand and the receptors and found that the receptor of Staphylococcus aureus shows the best interaction than the receptor of Escherichia coli with Schiff base ligand. The synthesized ligand and its metal complexes were also screened for their antibacterial and antifungal activity against bacterial species and fungi. The activity data showed that the metal complexes are found to have antibacterial and antifungal activity higher than the parent ligand.