(PF6)2

[Ru(dppn)2phen](PF6)2 (compound 4) is a polypyridylruthenium compound used in photodynamic therapy (PDT). [Ru(dppn)2phen](PF6)2 is normally nontoxic under dark conditions and induces mitochondrial respiratory damage upon light exposure. [Ru(dppn)2phen](PF6)2 exhibits high levels of singlet oxygen quantum yield and phototoxicity against cancer cells.