Electrochemical studies and potential anticancer activity in ferrocene derivatives

Several ferrocene derivatives (five mononuclear and two binuclear), including the new N-(p-chlorophenyl)-carboxamidoferrocene (1), were synthesized and their anticancer activity investigated. Two of them, 3 and 7, bearing a benzimidazole backbone were the most active against HeLa cells achieving IC50 values of ~5 μM along with 4 with a dipyridylamine ligand (~6 μM). Complex 6, also with a benzimidazole backbone, displayed slightly higher values (~11 μM). Cyclic voltammetry studies show that while the non-cytotoxic ferrocene derivatives 1, 2, and 5 follow a ferrocene-based redox behavior, derivatives 3, 4, 6, and 7 exhibit a more complex mechanism. These complex mechanisms are consistent with a more effective cytotoxic activity. Mössbauer spectroscopy parameters reflect a very small influence of the substituents.