Aminophosphine ligands as a privileged platform for development of antitumoral ruthenium(ii) arene complexes

The rapid and modular synthesis of the aminophosphine core has been exploited as a tool for rapid development of antitumoral metallodrug candidates. Starting with a series of structurally diverse aminophosphines, all obtained in a single step from commercial amines, a family of Ru(ii)-cymene complexes have been generated and tested in vitro for anti-tumoral activity in a series of cell lines, including the platinum-resistant A2780R. Through this approach, Ru(ii)-aminophosphine complexes have been identified with the IC₅₀ value range as low as 10-0.8 μM. Several biological assays were carried out to gain insight into the mechanism of action. Cell death by apoptosis and pH-independent action has been demonstrated. In addition, a selective cytotoxicity profile for tumoral cells over non-tumoral cells has been identified. Importantly, for the key candidates no loss of activity was observed when applied to the Pt-resistant A2780R, which highlights the potential utility of the bis-phospinoamine scaffold as an easily-tunable auxiliary ligand core in both drug discovery and subsequently a logical design of new anticancer metal-containing drugs. The complexes are characterised by NMR spectroscopy, mass spectrometry and single-crystal X-ray diffraction.