(η6-Arene)ruthenium complexes with P-coordinated phosphinoferrocene amides bearing extended polar substituents at the amide nitrogen: Synthesis, characterization and cytotoxicity

•A series of heterobimetallic Fe–Ru complexes was synthesized.•The complexes combine (η6-p-cymene)Ru(II) and phosphinoferrocene subunits.•Terminal substituents in ferrocene phosphino-amide donors are varied.•Cytotoxic activity was evaluated against human ovarian cancer cells.

Heterobimetallic Ru–Fe complexes of the general formula [(η6-p-cymene)RuCl2(Ph2PfcCONHCH2CH2COY-κP)], where Y = Me, NH2, NHEt, NHPh, and NMe2, and fc = ferrocene-1,1′-diyl, were synthesized from p-cymene ruthenium dichloride dimer and phosphinoferrocene carboxamide ligands bearing extended urea or acetamido substituents at the amide nitrogen. All the compounds were fully characterized by analytical and spectroscopic methods and, for one representative, also by single-crystal X-ray diffraction analysis. The cytotoxicity of these complexes was examined. The compounds displayed modest antiproliferative activity towards human ovarian cancer cell lines, the exception being a complex with a terminal N-phenylurea moiety which has IC50 values of ca. 20 μM.

Graphical abstractComplexes [(η6-p-cymene)RuCl2(Ph2PfcCONHCH2CH2COY-κP)], where Y = Me, NH2, NHEt, NHPh, and NMe2, and fc is ferrocene-1,1′-diyl, were synthesized and characterized by elemental analysis, multinuclear NMR and IR spectroscopy and mass spectrometry. The molecular structure of [(η6-p-cymene)RuCl2(Ph2PfcCONHCH2CH2COMe-κP)] was determined by single-crystal X-ray diffraction analysis. Cytotoxicity tests showed that these Ru–Fe complexes display modest cytotoxicity towards the human ovarian cancer cell lines, the exception being the complex with terminal N-phenylurea moiety, showing IC50 values of ca. 20 μM.Figure optionsDownload full-size imageDownload as PowerPoint slide