Synthesis, structural characterization, electrochemical and biological studies on divalent metal chelates of a new ligand derived from pharmaceutical preservative, dehydroacetic acid, with 1,4-diaminobenzene

Cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes of new 3-acetyl-4-[(4-aminophenyl)amino]-6-methyl-2H-pyran-2-one (HL1) derived from dehydroacetic acid and 1,4-diaminobenzene were prepared and characterized. The structural features were determined from their elemental analyses, H-1, and C-13-NMR spectra, molar conductivities, magnetic moments, IR, UVvis. spectra, thermal analyses (D.T.A. and T.G.A.) and E.S.R. measurements. Their magnetic susceptibility measurements and low conductance data provide evidence for the mono-or dimeric and non-electrolytic nature of the solid complexes. The E.S.R. spectra of copper( II) complexes show axial type symmetry with covalent or ionic bond character. The electro-chemical behavior of the complexes in DMF (dimethylformamide) solvent at 298 K was studied. The biological activity of the ligand and its metal(II) complexes was also studied. The obtained complexes showed higher activities than the free ligand in protecting the Egyptian cotton fields from Spodoptera littoralis larvae. (C) 2014 King Saud University. Production and hosting by Elsevier B.V.