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

摘要

The solid complexes of oxovaladium(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)-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).2H_2O], where M = Mn(II), Fe(II), Co(II), Ni(II) and Cu(II). Oxovanadium(IV) 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 octahedral stereochemistry. The fungicidal activities of the ligand and the metal complexes have been screened in vitro against the organism Aspergillus niger and the percentage of inhibition has been found to be in the order: Cu(II) > Ni(II) > Fe(II) > Co(II) > Mn(II) > VO(IV).