Synthesis and Characterization of Piano-Stool Ruthenium(II)-Arene Complexes of Isatin Schiff Bases: Cytotoxicity and DNA Intercalation

A series of aryl-isatin Schiff base derivatives (3a-d) and their piano-stool ruthenium complexes (4a-d) were synthesized and characterized via H-1 and C-13 NMR and Fourier transform infrared (FTIR) spectroscopy. In addition, the purity of all of the compounds (3a-c and 4a-d) was determined via elemental analysis. Complex 4d was analyzed using X-ray crystallography. An in vitro antiproliferative study of the compounds (3a-c and 4a-d) against human hepatocellular carcinoma (HEPG2), human breast cancer (MCF-7), human prostate cancer (PC-3), and human embryonic kidney (HEK-293) cells exhibited their considerable antiproliferative activity. 4d exhibited effective cytotoxicity against HEPG2 and MCF-7. It displayed higher cytotoxicity than the reference metallo-drug cisplatin. Moreover, the stability of 4d was studied via 1H NMR spectroscopy, and the binding model between 4d and DNA was investigated via ultraviolet-visible spectroscopy. The lipophilicity of the synthesized complexes was determined using an extraction method.