Novel vic-dioximes: Synthesis, complexation with transition metal ions, spectral studies and biological activity

A novel, substituted disodium-4-hydroxy-5-{[(1E,2E)-N-hydroxy-2-(hydroxyimino)ethanimidoyl]amino}naphthalene-2,7-disulfonate vic-dioxime ligand (LH2) was synthesized from 4-amino-5-hydroxy-2,7-naphthalenedisulfonic acid disodium salt and (E,E)-monochloroglyoxime at room temperature. The mononuclear CuII, NiII, ZnII and CdII complexes of this vic-dioxime ligand were prepared and their structures confirmed by elemental analysis, IR and UV–visible spectroscopy; the 1H and 13C NMR spectra of the LH2 ligand (1) were also recorded. The oxime ligand, LH2, acts as a bidentate ligand bending through nitrogen atoms in the presence of base. Elemental analyses indicated that the ligand:metal ratio was 2:1 in the cases of CuII and NiII complexes and 1:1 in the cases of ZnII and CdII complexes. The ligand was screened for its antimicrobial activity against the fungi Rhodotorula rubra, Kluyveromyces marxianus, Aspergillus fumigatus and Mucor pusillus and this was compared to that of metal complexes derived from it.