New heteroleptic palladium complexes with amino acid and bornane ligands: synthesis and antibacterial activity

Novel chiral palladium complexes containing camphor benzylimine and l-amino acids (proline, tyrosine, serine, isoleucine) as ligands were synthesized and characterized by elemental analysis and by NMR and IR spectroscopies. The antibacterial activity of the new and previously synthesized complexes and reference compounds against the bacteria MRSA, S. aureus, P. aeruginosa, E. coli, and M. vaccae was studied. It was found that the introduction of an amino acid ligand does not contribute to the activity of the mononuclear complex compared to the starting binuclear analogue. The binuclear palladacycle obtained from camphor benzylimine showed the highest activity against the pathogenic strains MRSA and M. vaccae (MIC = 8 mg L⁻¹), which is comparable with that of the clinical antibiotics used for comparison.