Highly potent extranuclear-targeted luminescent iridium(III) antitumor agents containing benzimidazole-based ligands with a handle for functionalization

A series of 6 substitutionally inert and luminescent iridium(III) antitumor agents of the type [Ir((CN)-N-boolean AND)(2)((NN)-N-boolean AND)][PF6] containing a benzimidazole (NN)-N-boolean AND ligand with an ester group as a handle for further functionalization has been prepared. They exhibit IC50 values in the high nanomolar range in some ovarian and breast cancer cell lines (approximately 100X more cytotoxic than cisplatin (CDDP) in MDA-MB-231) and are located in the actin cortex predominantly as shown by confocal luminescence microscopy. This discovery could open the door to a new large family of drug bioconjugates with diverse and simultaneous functions.