Synthesis and Cytotoxicity of Arene‐Ru Compounds Containing 4‐Nitroaniline or 2‐Halogenated 4‐Nitroaniline

The compounds [(η6-p-cymene)RuCl2(4-nitroaniline)] and [(η6-p-cymene)RuCl2(2-halogen-4-nitroaniline)] were synthesized and characterized by various means. The [(η6-p-cymene)RuCl2(4-nitroaniline)] and [(η6-p-cymene)RuCl2(2-fluoro-4-nitroaniline)] compounds were determined by X-ray diffraction, appearing in a distorted piano-stool type of arrangement with similar bond lengths and angles around the ruthenium. The compounds exhibited moderate to strong in vitro cytotoxicity against A549 and MCF-7 human cancer cells. Substitution of heavy halogen atom on the ortho position of para-nitroaniline weakened the cytotoxicity against both of MCF-7 and A549, except the cases of fluorine substitution for hydrogen atom regarding A549 and bromine substitution for chlorine atom regarding MCF-7, which showed minor deviation.