International Research Journal of Pure and Applied Chemistry

The synthesis, spectroscopic (IR, electronic, ¹HNMR and mass), magnetic, thermal  and conductance measurements with in-vitro antibacterial and anticancer evaluation on Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Pd(II) complexes of the Schiff base, 3-(-1-(4-methoxy-6-methyl)-2-pyrimidinylimino)methyl-2-napthol are reported. The ligand coordinates through the azomethine N and napthol O atoms, resulting in an N₂O₂ chromophore around the central metal atom. The room temperature magnetic moment, thermal, IR and electronic spectral measurements are consistent with the adoption of a 4-coordinate square planar/ tetrahedral  geometry for the Co(II), Cu(II), Ni(II), Zn(II) and Pd(II) complexes; and a 6-coordinate octahedral geometry for the Mn(II) complex, with water occupying the fifth and sixth coordination sites. The complexes are magnetically dilute and non-electrolyte in DMSO. The in-vitro antibacterial studies show that the complexes are more active than the ligand and the Cu(II) complex exhibits a broad-spectrum antibacterial activity against Enterococcus cloacae, Serratia liquefaciens, Staphyloccus aureus, Escherichia coli, Chromobacter violaceum, Klebsiella sp and Bacillus sp with inhibitory zones range of 7.0-12.0 mm. The in-vitro cytotoxic studies show that the ligand is not active against HL-60 (Leukaemia) cells, but is resistant to 518A2 (Melanoma) cells with IC₅₀ of about 70.03 µm. It is interesting to note that the Pd(II) complex exhibits super in-vitro anticancer activities against both 518A2(melanoma) and HL-60(Leukaemia) carcinomas with IC₅₀ values of about 1.34  and 1.85 µM, which exceed Cisplatin activities of 35.0 and 3.5 µM in the same assay respectively.