Synthesis and characterization of manganese(II), cobalt(II), nickel(III), and copper(II) complexes of Schiff base derivatives of dehydroacetic acid

The solid complexes of Mn(EI), Co(II), Ni(II) and Cu(II)) with the Schiff b ases derived from 3-acetyl-6-methyl-(2H)-pyran-2,4(3H) dione (dehydroacetic acid) and aniline, p-chloroaniline, p-iodoaniline and p-phenetidine have b een prepared and characterised by elemental analysis, conductance, magnetic , thermal, IR, UV/visible and NMR spectral studies. The ligand field parame ters have been evaluated for Co(II), M(II) and Cu(II) complexes which sugge st an octahedral geometry for each of them, The elemental analysis, magneti c moment and spectral data suggest the dimeric nature of Mn(II) complexes, with octahedral geometry. The fungicidal activities of the ligand and their metal complexes have been screened in vitro against Aspergillus niger and the percentage inhibition of the metal complexes is found to be increased c onsiderably than that of their corresponding ligands and the order is Cu > Ni > Mn > Co.