Anticancer activity of new organo-ruthenium, rhodium and iridium complexes containing the 2-(pyridine-2-yl)thiazole <i>N</i>,<i>N</i>-chelating ligand

The dinuclear dichloro complexes [(η⁶-arene)₂Ru₂(μ-Cl)₂Cl₂] and [(η⁵-C₅Me₅)₂M₂ (μ-Cl)₂Cl₂] react with 2-(pyridine-2-yl)thiazole (pyTz) to afford the cationic complexes [(η⁶-arene)Ru(pyTz)Cl]⁺ (arene = C₆H₆<b>1</b>, <i>p-ⁱ</i>PrC₆H₄Me <b>2</b> or C₆Me₆<b>3</b>) and [(η⁵-C₅Me₅)M(pyTz)Cl]⁺ (M = Rh <b>4</b> or Ir <b>5</b>), isolated as the chloride salts. The reaction of <b>2</b> and <b>3</b> with SnCl₂ leads to the dinuclear heterometallic trichlorostannyl derivatives [(η⁶-<i>p-ⁱ</i>PrC₆H₄Me)Ru(pyTz)(SnCl₃)]⁺ (<b>6</b>) and [(η⁶-C₆Me₆)Ru(pyTz)(SnCl₃)]⁺ (<b>7</b>), respectively, also isolated as the chloride salts. The molecular structures of <b>4</b>, <b>5</b> and <b>7</b> have been established by single-crystal X-ray structure analyses of the corresponding hexafluorophosphate salts. The <i>in vitro</i> anticancer activities of the metal complexes on human ovarian cancer cell lines A2780 and A2780cisR (cisplatin-resistant), as well as their interactions with plasmid DNA and the model protein ubiquitin, have been investigated.