TEMPLATE SYNTHESIS AND SPECTRAL STUDIES OF BIOLOGICALLY ACTIVE NI(II), AND CU(II) TRANSITION METAL COMPLEXES OF TETRADENTATE AZA-OXO (N2O2) MACROCYCLIC LIGAND

A novel series of transition metal complexes of [M(C₁₉H₁₈N₂O₂S)X₂], where M = Ni(II), Cu(II), X = Cl^–, NO₃^–, ½ SO₄^2- and (C₁₉H₁₈N₂O₂S) moiety corresponds to the tetradentate aza-oxo macrocyclic species, were synthesized by template condensation reaction of 1,4-bis(2-formylphenoxy)butane and thiourea in the presence of divalent metal salts in 1:1:1 ratio. The metal complexes were characterized and analyzed by elemental analyses, molar conductance, magnetic measurements, and spectral techniques like IR, mass, UV-VIS, electron paramagnetic resonance spectroscopy, and thermal studies. The low values of the molar conductance values indicate the non-electrolytic nature of synthesized complexes except nitrato complex of Ni (II) which is 1:2 electrolytic in nature. Based on aforesaid spectral studies, [Cu(C₁₉H₁₈N₂O₂S)(SO₄)] complex may possess trigonal bipyramidal geometry, [Ni(C₁₉H₁₈N₂O₂S)](NO₃)₂ complex tetrahedral geometry and rest of the complexes six coordinated octahedral/tetragonal geometry. To explore the complexes in the biological field, synthesized transition metal complexes were examined against the pathogens A. niger, S. rolfsii, F. oxysporum, and A. brassicae. All metal complexes displayed good antifungal activity.