Homo- and Heteroleptic Phototoxic Dinuclear Metallo-Intercalators Based on RuII(dppn) Intercalating Moieties: Synthesis, Optical, and Biological Studies

Using a new mononuclear building block, for the first time, a dinuclear Ru-II(dppn) complex and a heteroleptic system containing both Ru-II(dppz) and Ru-II(dppn) moieties are reported. The complexes, including the mixed dppz/dppn system, are O-1(2) sensitizers. However, unlike the homoleptic dppn systems, the mixed dppz/dppn complex also displays a luminescence switch on DNA light-switch effect. In both cisplatin sensitive and resistant human ovarian carcinoma lines the dinuclear complexes show enhanced uptake compared to their mononuclear analogue. Thanks to a favorable combination of singlet oxygen generation and cellular uptake properties all three of the new complexes are phototoxic and display potent activity against chemotherapeutically resistant cells.