Synergistic Effects of Metals in a Promising Ru(II) -Pt(II) Assembly for a Combined Anticancer Approach: Theoretical Exploration of the Photophysical Properties.

Ru(II) -Pt(II) complexes are a class of bioactive molecules of interest as anticancer agents that combine a light-absorbing chromophore with a cisplatin-like unit. The results of a DFT and TDDFT investigation of a Ru(II) complex and its conjugate with a cis-PtCl2 moiety reveal that a synergistic effect of the metals makes the assembly a promising multitarget anticancer drug. Inspection of type I and type II photoreactions and spin-orbit coupling computations reveals that the cis-PtCl2 moiety improves the photophysical properties of the Ru(II) chromophore, ensuring efficient singlet oxygen generation and making the assembly suitable for photodynamic therapy. At the same time, the Ru(II) chromophore promotes a new alternative activation mechanism of the Pt(II) ligand via a triplet metal-to-ligand charge transfer ((3) MLCT) state, before reaching the biological target. The importance of the supramolecular architecture is accurately derived, opening interesting new perspectives on the use of bimetallic Ru(II) -Pt(II) assemblies in a combined anticancer approach.