Synthesis, characterization and antimicrobial activity of some transition metal complexes of N-(5-chloro-2-hydroxyphenyl)-3-methoxy-salicylaldimine

Abstract

Cr(III), Fe(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II) complexes of N-(5-chloro-2-hydroxyphenyl)-3-methoxy-salicylaldimine (H₂L), an ONO type tridentate ligand, were synthesized and characterized by elemental analysis, magnetic moment, molar conductivity, TGA, NMR, IR, UV-vis. and ESI-MS spectral techniques. All of the complexes except [Zn(L)(H₂O)₂] are paramagnetic. The CoCl₂ gives a complex with 1:2 M:L ratio while the others form 1:1 non-ionic complexes with H₂L. The ligand coordinated to the metal ions through the both OH oxygen and the azomethine nitrogen atoms acting tridentate behaviour. Octahedral geometry has been proposed for the Fe(II), Cr(III), Co(II), Ni(II) complexes considering the magnetic moment values and the electronic spectral data. The Zn(II) and Fe(III) complexes exhibit five coordination geometries and the Cu(II) complex is four-coordinated having acetato bridged dimeric structure. Antimicrobial activities of the compounds were determined against six bacteria and C. albicans as fungi. The Ni(II) and Co(II) complexes exhibit considerable selective activity on S. epidermidis and C. albicans whereas the ligand has no activity on the microorganisms. In addition, the Cr(III) complex shows antibacterial activity toward S. epidermidis and the Zn(II) complex has antifungal activity on C. albicans.

KEY WORDS: Schiff base, Salicylaldimine, 5-Chloro-2-hydroxyphenyl, Transition metal complexes, Antimicrobial

Bull. Chem. Soc. Ethiop. 2015, 29(1), 63-74

DOI: http://dx.doi.org/10.4314/bcse.v29i1.6