SYNTHESIS, CHARACTERIZATION AND ANTIBACTERIAL ACTIVITIES OF SOME TRANSITION METAL COMPLEXES DERIVED FROM NOVEL LIGAND 2-{(E)-[(3-HYDROXYQUINOXALIN-2-YL) METHYLIDENE] AMINO}-3-PHENYLPROPANOIC ACID (HQMP) METAL COMPLEXES

Abstract

The complexes of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with a new Schiff base, 2-{(E)-[(3-hydroxyquinoxalin-2- yl)methylidene]amino}-3-phenylpropanoic acid (HQMP) formed by the condensation of Phenylalanine with 3- Hydroxyquinoxaline-2-carboxaldehyde was synthesized and characterized by elemental analysis, conductivity, UVvisible, FT-IR, 1H NMR,TGA-DTA, Powder X-ray analysis and magnetic susceptibility measurements. All the complexes exhibit 1: 1 metal to ligand ratio. 1H NMR study shows that Phenolic O-H of ligand participates in complex formation. Coordination of azomethine nitrogen and phenolic oxygen are evidenced by IR data from the band of M-O and M-N. Electronic spectral data suggest octahedral geometry for Co(II) complexes while tetrahedral geometry for Mn(II), Ni(II),Cu(II) and Zn(II) complexes. Coordinated and lattice water molecules in the complexes are evidenced by TGA-DTA curve and the presence of the characteristic stretching band in the IR spectrum. Powder X-ray data is evidence that [Mn(HQMP)H2O].H2O complex exhibits Triclinic crystal system while [Cu(HQMP)H2O]H2O and [Zn(HQMP)H2O]H2O complex exhibit monoclinic crystal system.. Ligand and its metal complexes were screened for their antibacterial activity against staphylococcus aureus, klebsiella pneumonia (Gram positive) and Escherichia coli, pseudomonas aerugenosa (Gram negative). It was observed that complexes are more potent bactericides than the ligand..