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(C∧ N)2 (N∧ N)][PF6 ] containing a benzimidazole N∧ N 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 100× 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.