Studies on mononuclear transition metal chelates derived from a novel (E,E)-dioxime:: synthesis, characterization and biological activity

A novel vic-dioxime ligand with a thiourea moiety, (4E,5E)-1,3-bis{4-[(4-bromophenylamino)-methylene] phenyl}-2-thiooxaimidazoline-4,5-dione dioxime (4) (bmdH(2)) has been synthesized from N,N'-bis{4-[(4-bromophenylamino)methylene]phenyl} thiourea and (E,E)-dichlorogly-oxime. The bmdH(2) ligand (4) forms transition metal complexes [M(bmdH)(2)] with a metal : ligand ratio of 1 : 2 with M = Ni(II), Co(II), and Cu(II). The mononuclear Ni(II), Co(II) and Cu(II) complexes, [Ni(bmdH)(2)] (5), [Co(bmdH)(2)] (6) and [Cu(bmdH)(2)] (7) have the metal ions coordinated through the two N, N atoms, as do most vic-dioximes. Elemental analyses, molar conductivity, magnetic susceptibility, IR, H-1 NMR spectra, and UV-Visible spectroscopy were used to elucidate the structures of the ligand and its complexes. Conductivity measurements have shown that the mononuclear complexes are non-electrolytes. In addition, the ligands and metal complexes were screened for antibacterial and antifungal activities by agar well diffusion techniques using DMF as solvent.