Synthesis, Characterization, and Antibacterial and Cytotoxic Study of Metal Complexes with Schiff Base Ligands

Abstract

The synthesis of 16 metal complexes from four Schiff bases prepared from 5-chloro-2-hydroxybenzaldehyde and primary amines has been described. The synthesized Schiff base ligands and their complexes were characterized by elemental analyses, spectroscopic (UV, IR, 1H and 13C NMR, electrospray ionization-mass spectrometry) methods, and magnetic and conductance measurements. Furthermore, complexes 1a, 1b, 3d, 4a, and 4d were characterized by X-ray diffraction analysis. After the structural characterization, all the compounds were tested in vitro for their antibacterial (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescens, and Staphylococcus aureus) activities. The cytotoxic activities of the synthesized compounds were evaluated in vitro against human chronic myeloid leukaemia cells (K562) and a human nasopharyngeal epidermoid tumour cell line. The results indicated that most of the complexes showed good cytotoxic activity against human cancer cell lines but weak cytotoxic activity against a human normal cell line (L02). Among the compounds tested, the cobalt complexes 1a, 2a, 3a, and 4a showed the most favourable antibacterial and cytotoxic activities.