Abstracto

Synthesis, Spectra and Biological Studies on some Metal (II) Complexes of 3-(6-methoxypyridin-3-ylimino)methyl)-6-methyl-2H-chromen-4-ol.

Aderoju A Osowole and Godwin H Etuk

Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) complexes of the Schiff base, 3-(6-methoxypyridin-3-ylimino)methyl)-6-methyl-2H-chromen-4-ol (HL), derived from the condensation of 5-amino-2-methoxypyridine and 6-methyl-3-formylchromone were synthesised and characterised by percentage metal, melting points, solubility, infrared and electronic spectra measurements. Furthermore, the in-vitro antibacterial activities of these complexes against Bacillus subtilis, Staphylococcus aureus, Proteus mirabilis, Klebsiella oxytoca, Pseudomonas aeruginosa, and Escherichia coli are reported. Infrared and percentage metal measurements indicated that the ligand coordinated to the metal ions through the imine nitrogen and chromenol oxygen atoms in the ratio 1M:1L, and the complexes analysed as [ML(NO3)] and [M(L)Cl.H2O] respectively. The IR and electronic spectral measurements corroborated the adoption of a 4-coordinate square planar/ tetrahedral geometry for the metal complexes. The Schiff base and its metal complexes were inactive against P. mirabilis and K. oxytoca but exhibited good antibacterial activity against S. aureus and E. coli with inhibitory zones range of 13.0-18.0 and 11.0-13.5 mm respectively. The complex, [Ni(L)Cl.H2O] exhibited a broad-spectrum antibacterial activity against S. aureus, P. aeruginosa, B. subtilis and E. coli with inhibitory zones range of 12.5-17.0.0 mm, proving its potential usefulness as a broad-spectrum antibacterial agent.