Synthesis and Antibacterial Evaluation of Cu(II), Co(II), and Mn(II) Complexes with Schiff Bases Derived from 5-Aminosalicylic Acid and o-Vanillin

Abstract

The current study is devoted to the synthesis of Schiff base ligand, HL, by condensation of 5-aminosalicylic acid with o-vanillin, followed by preparing its Cu(II), Co(II), Mn(II), and Zn(II) complexes, and their characterization. The Schiff base behaves as a bidentate ligand which forms tetrahedral complexes with Cu(II) and Zn(II), unlike Co(II) and Mn(II) that give octahedral complexes. The Schiff base ligand and its complexes with Cu²⁺, Co²⁺, Mn²⁺, and Zn²⁺ exhibit considerable antibacterial activity against some drug resistant reference strains and local isolates of S. aureus, E. Coli, P. aersginosa. Overall, the metal complexes exhibit more potent antibacterial activity than the ligand HL alone.