Synthesis, characterization and cytotoxic studies of water soluble [(η5-C5H5)2Mo(thionucleobase/thionucleoside)]Cl complexes in breast and colon cancer cell lines

► Mo(IV) could be coordinated by the nearby amino acids in the estrogen receptor ligand binding domain behaving as an agonist. ► Synergism between Cp2Mo2+ and 2-amino-6-mercaptopurine leads to highly antitumor species in MCF-7. ► Incorporation of Cp2Mo2+ into the thionucleobase increases transport across the cell membrane.