Synthesis and biological evaluation of a novel ONS tridentate Schiff base bearing pyrimidine ring and some metal complexes

The new Schiff base ligand (1-[[1-(5-chloro-2-hydroxyphenyl)ethyliden]amino]-4-phenyl-5-benzoyl-pyrimidine-2-thione) and its Cu(II), Co(II), Pd(II), and Mn(II) complexes were synthesized and characterized by elemental and molar conductance, UV-Vis, IR, NMR spectra, magnetic moment as well as mass spectra. While Pd(II) complexes exhibited square planar geometry, the others displayed octahedral geometry. The complexes showed nonelectrolytic behavior. All the compounds were evaluated for in vitro antimicrobial efficiency against Gram-positive bacteria, Gram-negative bacteria, and yeast using microdilution procedure. This study suggested that the [Co(L)(2)]center dot 3H(2)O (1b) and [Mn(L)(2)]center dot 2H(2)O (1d) complexes might be new potential antimicrobial substances against bacteria and fungi.