Synthesis, characterization, chelation with transition metal ions, and antibacterial and antifungal studies of the 4-[(E)- -phenyldiazenyl]-2-[(E)-(phenylimino)methyl]phenol dye

Abstract

New Ni(II), Cu(II) and Co(II) complexes were synthesized with the bidentate azo-azomethine dye, 4-[(E)-phenyldiazenyl]-2-[(E)-(phenylimino)methyl] phenol (dmpH), which was prepared by the reaction of 2-hydroxy-5-[(E)- phenyldiazenyl]benzaldehyde with aniline in EtOH. The syntheses of the metal chelates of the azo-azomethine dye were realized by the precipitation technique. The synthesized metal complexes were characterized by elemental analysis, molar conductance measurements, as well as infrared and UV-Vis spectral data. Based on these characterizations, the metal complexes of the transition metal ions may be formulated as [M(dmp)Cl(H2O)] where M = Ni(II), Cu(II) and Co(II). The metal complexes were formed by the coordination of N and O atoms of the ligand. The molar conductance values of the Ni(II), Cu(II) and Co(II) complexes of the bidentate ligand indicate their non-ionic character. The free ligand and its metal complexes were tested for their in vitro antimicrobial properties against eight bacteria: Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Mycobacterium smegmatis, Pseudomonas aeruginosa, Enterococcus cloacae, Bacillus megaterium, and Micrococcus luteus, and three fungi, Kluyveromyces fragilis, Rhodotorula rubra and Saccharomyces cerevisiae, in order to assess their antimicrobial potential. The [Ni(dmp)Cl(H2O)] chelate exhibited high activity against all the bacteria and fungi, except Rhodotorula rubra.