SYNTHESIS AND CHARACTERIZATION OF MIXED LIGAND Mn(II), Co(II), Ni(II) and Cu(II) COMPLEXES OF SOME HYDRAZONES AND NITROGEN DONOR LIGANDS

Abstract

  Mn(II), Co(II), Ni(II) and Cu(II) mixed ligand complexes of some Benzoyl hydrazones (hydrazide Schiff bases) with 1,10-Phenanthroline (Phen), 2,2′-bipyridine and ethylenediamine(en) were synthesized and characterized using metal analysis, molar conductivity, magnetic susceptibility, electronic spectra, infrared measurement and antimicrobial activity. The percentage metals of the complexes are in close agreement with their corresponding theoretical values. The molar conductance of some of the complexes that were soluble in nitromethane reveals that only [Co(H₁L)₂Bipy]Cl₂ is a 1:2 electrolyte while [Cu(Phen)(H₁)](NO₃)H₂O, [Cu(Bipy)H₁L]NO₃, [Cu(Phen)H₁L]NO₃, [Cu(H₁L)(H₁A)(NO₃)H₂O]NO₃, and [Cu(H₁HY)(H₁A)(NO₃)H₂O].NO₃.2H₂O are 1:1 electrolyte. The electronic spectra displayed bands which were assigned to π→π^*, n→π^*, Charge transfer and d-d transitions. From the d-d transitions in the visible region of the spectra, it was suggested that these complexes have four-, five- and six- coordinate stereochemistries. The proposed geometries were backed up by the observed magnetic moments which were in line with the expected or theoretical values.  The infrared spectra gave bands that were assigned to ѵ(NH), azomethine ѵ(C=N) and ѵ(C=O) vibrational frequencies. The shift in the ѵ(C=O), ѵ(N-N), ѵ(NH), ѵ(C-N) and ѵ(C=N) bands in the spectra of the complexes reveals that there is coordination of the ligands to the metal centre. The complexes compared favourably well with Gentamicin and Ketoconazole with respect to antibacterial and antifungal activities respectively.