Design, synthesis, characterization and antibacterial and antifungal activity of a new 2-{(E)-[(4-aminophenyl)imino]-methyl}-4,6-dichlorophenol and its complexes with Co(II), Ni(II), Cu(II) and Zn(II): An experimental and DFT study

Abstract

In this study, the complexes of Co (II), Ni (II), Cu (II) and Zn (II) with 2-(E)-(4-aminophenylimino)methyl-4,6-dichlorophenol were prepared and characterized by physical, spectral and analytical data. The metal: ligand stoichiometric ratio is 1:2 in all the complexes. The results suggested that the Schiff bases are coordinated to the metal ions through the phenolic oxygens and azomethine nitrogen to give mononuclear complexes. Their structures were elucidated on the basis of elemental analysis, IR, 1H and 13C NMR spectra, UV-VIS, magnetic susceptibility measurements and thermogravimetric analyses. Both the antibacterial and antifungal activities and MIC values of compounds were reported. Among the tested compounds, the most effective compound providing a MIC value of 64 μg/mL is Zn(L)2 against C. tropicalis and B. subtilis. The theoretically optimized geometries of complexes have tetrahedral structures. The computed stretching frequencies of C=N, C-O and N-H bonds were found to be in good agreement with experimental data. All calculated frequencies fall within about 5% of the experimental frequency regions.

Keywords

• Schiff base
• transition metal complex
• antibacterial and antifungal activities
• DFT