Synthesis, Spectral Characterization, in vitro cytotoxicity and antibacterial studies of a Novel Schiff Base Ligand derived from S-Carboxy Methyl-L-Cysteine and 5-Chloroisatin and its Cu(II), Ni(II) and Co(II) Metal complexes

A novel chiral Schiff base ligand, namely S-Carboxy Methyl-L-Cysteine 5-Chloroisatin (CMCCI) was synthesized through the condensation of the chiral amino acid S-Carboxy Methyl-L-Cysteine and 5-Chloroisatin in basic medium. The resulting amino acid Schiff base ligand and its metal complexes with Cu(II), Ni(II) and Co(II) were characterized using elemental analysis, FTIR, 1H NMR and UV-visible spectroscopy, confirming the formation of CMCCI and (CMCCI)2M type metal complexes. The formation of the ligand CMCCI was also confirmed by mass spectral analysis. The analytical results suggested that the Schiff base behaves as tridentate ONO donor ligand and coordinates with Cu(II), Ni(II) and Co(II) ions in octahedral geometry. The ligands and their complexes were screened for their cytotoxicity and antibacterial activities. Cytotoxicity studies revealed that the Schiff base complexes of copper exhibited considerable cytotoxic effects than the Schiff base ligand. Copper complex showed high cytotoxicity even in lower concentrations and can be used as a potential anticancer drug after further studies. Antibacterial studies of the ligand and metal complexes were performed against Staphylococcus aureus and Escherichia coli, Gram positive and Gram negative bacterial strains respectively. Copper complex exhibited considerable activity against Staphylococcus aureus and cobalt complex showed moderate activity against Escherichia coli.