Mono- and dinuclear (η⁶-arene) ruthenium(II) benzaldehyde thiosemicarbazone complexes: Synthesis, characterization and cytotoxicity

A series of mono- and dinuclear (η⁶-arene) ruthenium(II) complexes were prepared by reaction of thiosemicarbazone ligands derived from benzaldehyde and ruthenium(II) precursors of the general formula [Ru(η⁶-arene)(μ-Cl)Cl]², where arene = <i>p-ⁱ</i>PrC⁶H⁴Me or C⁶H⁵C³H⁶COOH. These complexes were characterized by NMR and IR spectroscopy, ESI-mass spectrometry and elemental analysis. The molecular structure of the mononuclear <i>p</i>-cymene complex was determined by X-ray diffraction analysis, revealing a pseudo-tetrahedral piano stool conformation and a bidentate <i>N,S</i> coordination mode of the thiosemicarbazone ligand. The complexes and ligands were evaluated for their <i>in vitro</i> cytotoxicity against the WHCO1 oesophageal cancer cell line.