Four complexes of the general formula [(eta(6)-p-MeC6H4Pri)(2)Ru-2(mu-SC2H4R)(3)](+), R = (CF2)(7)CF3 (1), (CF2)(5)CF3 (2), (CF2)(3)CF3 (3) and (CH2)(5)CH3 (4) were synthesized and characterized. The molecular structures of complexes 1 and 3 were confirmed by single crystal X-ray diffraction analysis of their chloride salts. Complexes 3 and 4 were evaluated for their antiproliferative activity against human ovarian cancer A2780 and A2780cisR cell lines and against the non-tumorigenic HEK293 cell line. Complexes 3 and 4 are highly cytotoxic (IC50 values in the nanomolar range) and exhibit a slight selectivity for cancer cells over the model healthy cells. (C) 2016 Elsevier B.V. All rights reserved.