Synthesis, Characterization, and Antitumor Activity of Water-Soluble (Arene)ruthenium(II) Derivatives of 1,3-Dimethyl-4-acylpyrazolon-5-ato Ligands. First Example of Ru(arene)(ligand) Antitumor Species Involving Simultaneous Ru−N7(guanine) Bonding and Ligand Intercalation to DNA

We report on the synthesis of novel water-soluble [(arene)RuII(Q)Cl] and [(arene)RuII(Q)(X)]BF4 compounds (arene = p-cymene, benzene, hexamethylbenzene; HQ = 1,3-dimethyl-4-R-(CO)-5-pyrazolone, HQMe, R = methyl, HQPh, R = phenyl, HQNaph, R = naphthyl; X = H2O, 9-ethylguanine), and their in vitro antitumor activity toward the cell lines MCF7 (HTB-22, human breast adenocarcinoma), HCT116 (CCL-247, human colorectal carcinoma), A2780 (human ovarian carcinoma), A549 (CCL-185, human lung carcinoma), and U87 MG (HTB-1, human glioblastoma). The X-ray crystal structures of two complexes were determined. One of them, {chlorido-(p-cymene)-[(1,3-dimethyl-4-(1-naphthoyl)-pyrazolon-5-ato]ruthenium(II)}, was also studied with density functional theory methods and was selected for docking on a DNA octamer showing intercalation between DNA bases by the naphthyl moiety and for Ru−N7(guanine) bonding.