Heterobimetallic Ru-Fe complexes of the general formula [(eta(6)-p-cymene) RuCl2(Ph(2)PfcCONHCH(2)CH(2-)COY-kappa P)], 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 mu M. (C) 2015 Elsevier B.V. All rights reserved.