Synthesis and anticancer activity evaluation of η(5)-C5(CH3)4R ruthenium complexes bearing chelating diphosphine ligands.

The complexes [RuCp*(PP)Cl] (Cp* = C5Me5; [], PP = dppm; [], PP = Xantphos), [RuCp(#)(PP)Cl] (Cp(#) = C5Me4(CH2)5OH; [], PP = dppm; [], PP = Xantphos) and [RuCp*(dppm)(CH3CN)][SbF6] [] were synthesized and evaluated in vitro as anticancer agents. Compounds gave nanomolar IC50 values against normoxic A2780 and HT-29 cell lines, and were also tested against hypoxic HT-29 cells, maintaining their high activity. Complex yielded an IC50 value of 0.55 ± 0.03 µM under a 0.1% O2 concentration.