Arene platinum group metal complexes containing imino-quinolyl ligands: synthesis and antibacterial studies

Abstract

Imino-quinolyl Schiff-base ligands have been prepared by the condensation reaction of substituted 2-aminopyridine and quinoline-2-carbaldehyde. The reaction of [(arene)MCl2]2 with imino-quinolyl Schiff-base ligands leads to the formation of cationic complexes [(arene)M(L)Cl]+ (1–12). Single crystal X-ray diffraction studies were used to confirm the coordination mode and structures of these complexes. The molecular structures of these complexes revealed that they adopt characteristic three-legged piano stool geometry with the metal coordinating through a terminal chloride and imino-quinolyl ligands in a bidentate chelating NN′ fashion. The ligand coordinates to the metal center through the nitrogen of the quinoline and the imine nitrogen forming a five-membered metallacycle. These compounds were evaluated for their in vitro antibacterial activity by the agar well diffusion method against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae strains. Results show that all the ligands and complexes inhibited the growth of bacteria.