Functionalized ferrocenes: The role of the para substituent on the phenoxy pendant group.

Six ferrocenecarboxylates with phenyl, 4-(1-pyrrol-1-yl)phenyl, 4-fluorophenyl, 4-chlorophenyl, 4-bromophenyl, 4-iodophenyl as pendant groups were synthesized and fully characterized by spectroscopic, electrochemical and X-ray diffraction methods. The anti-proliferative activity of these complexes were investigated in hormone dependent MCF-7 breast cancer and MCF-10A normal breast cell lines, to determine the role of the para substituent on the phenoxy pendant group. The 4-fluorophenyl ferrocenecarboxylate is inactive in both cell lines while 4-(1-pyrrol-1-yl)phenyl ferrocenecarboxylate is highly cytotoxic in both cell lines.