Solvolysis and cytotoxicity of dinuclear ruthenium(II)-2,2′-bipyridine complexes with various bridged-ligands

• Published in: Inorganica Chimica Acta 2013-01, Vol.394, p.190-195
• Main Authors: Yamada, Takeshi, Noguchi, Yukiko, Nakai, Misaki, Yamauchi, Osamu, Nakabayashi, Yasuo, Sato, Takaji, Tamai, Yusuke, Chikuma, Masahiko, Mino, Yoshiki
• Format: Article
• Language: English
• Subjects: Antitumor agent; Cytotoxicity; Dimethyl sulfoxide (dmso); Dinuclear ruthenium(II) complexes; Solvolysis reaction
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2012.08.001

The UV–Vis spectra of [Ru2Cl2-dado]2+ in H2O–dmso (1:1 v/v) result in dramatic changes. [Ru2Cl2-BL]2+ complexes exhibit much lower cytotoxicity compare to cisplatin. However, [{Ru(dmso-S)(bpy)2}2(μ-BL)]4+ complexes produced in H2O–dmso are found to much more cytotoxic than [Ru2Cl2-BL]2+. [Display omitted] ► The UV–Vis spectra of [Ru2Cl2-BL]2+ in H2O–dmso (1:1 v/v) result in dramatic changes. ► The rate constants for the solvolysis are correlated with the redox potentials. ► The dmso ligand would make significant contributions to the cytotoxicity. In order to reveal the solvolysis reactions of dinuclear ruthenium(II)-2,2′-bipyridine complexes with various bridged-ligands (BL), [{RuCl(bpy)2}2(μ-BL)]2+ ([Ru2Cl2-BL]2+), we have studied the kinetics of these complexes in H2O and H2O–dmso (1:1 v/v). In H2O–dmso (1:1 v/v), time-course UV–Vis absorption and IR spectra indicate that the labile Cl− ligands of [Ru2Cl2-BL]2+ are successively substituted by H2O followed by dmso, [{Ru(dmso-S)(bpy)2}2(μ-BL)]4+. Cytotoxicity assays of dinuclear ruthenium(II) complexes were performed in L1210 murine leukemia cell line. [Ru2Cl2-BL]2+ complexes exhibit much lower cytotoxicity compare to cisplatin. However, [{Ru(dmso-S)(bpy)2}2(μ-BL)]4+ complexes produced in H2O–dmso are found to much more cytotoxic than [Ru2Cl2-BL]2+ and in particular the cytotoxicity of [{Ru(dmso-S)(bpy)2}2(μ-dado)]4+ (dado=1,12-diaminododecane) is comparable to that of cisplatin.