Synthesis, complexation, spectral, antibacterial and antifungal activity of 2,4-dihydroxy-5-[(E)- phenyldiazenyl]benzaldehyde oxime

摘要

A new substituted salicylaldoxime ligand containing an azo (-N=N-) group, 2,4-dihydroxy-5-[(E)-phenyldiazenyl]benzaldehyde oxime (H3salox) (2), was synthesized by the reaction of 2,4-dihydroxy-5-[(E)- phenyldiazenyl]benzaldehyde (1) with hydroxylamine in ethanolic solution at room temperature. Mononuclear complexes of (H3salox) (2), a bidentate hydroxyaldoxime ligand, were synthesized by reaction with nickel(II), cobalt(II) and copper(II) chloride salts. The complexes, [Ni(H2salox)2] (3), [Cu(H2salox)2] (4) and [Co(H2salox)2] (5) were characterized by elemental analyses (C, H, N), conductivity measurements and infrared and electronic spectral studies. The 1H-NMR spectrum of the H3salox (2) ligand was also recorded. The mononuclear Ni(II), Co(II) and Cu(II) complexes of the ligand, (H3salox), have a metal: ligand ratio of 1:2 and the ligand coordinates through the N and O atoms, as is the case with most hydroxyaldoximes. The molar conductivities in DMF solution indicate the non-electrolytic nature of the metal chelates. The antimicrobial activities of the ligand and its metal complexes were estimated for eight bacteria, i.e., Escherichia coli, Staphylococcus aureus, Klebsiella pneumoniae, Mycobacterium smegmatis, Pseudomonas aeruginosa, Enterococcus cloacae, Bacillus megaterium and Micrococcus luteus and three fungi, i.e., Kluyveromyces fragilis, Rhodotorula rubra and Saccharomyces cerevisiae.