Studies on DNA Cleavage and Antimicrobial Screening of Transition Metal(II) Complexes Derived from Tetradentate Schiff Base

A new series of transition metal complexes of Cu(II), Ni(II), Co(II), Mn(II), Zn(II), VO(IV), Hg(II) and Cd(II) have been synthesized from the Schiff base (H2L) derived from 4-aminoantipyrine, 3-hydroxy-4-nitrobenzaldehyde and 2-aminophenol. The structural features have been arrived from their elemental analyses, magnetic susceptibility, molar conductance, mass, IR, UV-Vis, 1H NMR and ESR spectral studies. The data show that the complexes have composition of ML type. The UV-Vis, magnetic susceptibility and ESR spectral data of the complexes suggest a square planar geometry around the central metal ion except VO(IV) complex which has square-pyramidal geometry. The redox behavior of copper and vanadyl complexes has been studied by cyclic voltammetry. The minimum inhibitory concentration (MIC) values of the in vestigated compounds indicate that the complexes have higher antimicrobial activity than the free ligand. The nuclease activity of the above metal complexes shows that only copper and nickel complexes cleave DNA through redox chemistry.