Tuning the redox activity of anticancer diiron complexes via derivatization of bridging hydrocarbyl ligands

Organoiron complexes offer exciting opportunities for developing new drug candidates, potentially addressing the limitations of traditional platinum chemotherapeutics. This work explores the design, synthesis, characterization and biological evaluation of novel diiron hydrocarbyl compounds, focusing on their redox modulation as a strategy to enhance anticancer effects. In particular, sulfur-, selenium-, and ferrocenyl-containing groups have been incorporated in the diiron scaffold, with a view to maintaining a suitable amphiphilic character of the resulting complexes. The new compounds have been fully characterized through spectroscopic methods, elemental analysis, and, in some cases, single crystal X-ray diffraction. Electrochemical analyses, as well as DNA and protein interaction studies, have been carried out to investigate peculiar aspects of the mechanism of action of selected complexes. The lipophilicity, water solubility, stability and speciation in aqueous media under pseudo-physiological conditions have been assessed via UV-Vis and NMR spectroscopy. The in vitro antiproliferative activity of selected compounds has been evaluated on a panel of tumoral and non-tumoral cell lines to estimate potency and selectivity, while the cellular redox status and cell death mechanism were investigated to clarify the mode of action.