Synthesis, characterization and biological studies of oxovanadium(IV), manganese(II), iron(II), cobalt(II), nickle(II) and copper(II) complexes derived from a quadridentate ligand

Abstract

nbsp; The solid complexes of oxovanadium(IV), Mn(II), Fe(II), Co(II), Ni(II) and (Cu(II) with a new quadridentate ligand (DHACH), derived from 3-acetyl-6-methyl-2H-pyran-2,4 (3H)dione (dehydroacetic acid) and carbohydrazide, have been synthesized and characterized by analytical, conductivity, thermal, magnetic, IR , ¹H NMR, UV-vis, mass and ESR spectral data. From the analytical and thermal data, the stoichiometry of the complexes has been found to be 1:1 (metal:ligand). The metal chelates have a general formula [M(DHACH).2H₂O], where M=Mn(II), Fe(II), Co(II), Ni(II) and Cu(II). Oxovanadium(IV)

complex has the composition [VO(DHACH).H₂O], IR spectral data suggest that the ligand, DHACH behaves as a dibasic quadridentate ligand with O:N:N:O donor sequence towards metal ions. The physico-chemical data suggest that all the complexes possess ocatahedral stereochemistry. The fungicidal activities of the ligand and the metal complexes have been screened ill <i>vitro</i> against the organism <i>Aspergillus niger </i>and the percentage of inhibition has been found to be in the order:<br><br>

Cu(II)>Ni(II)> Fe(II)>Co(II)> Mn(II)>VO(IV)