Synthesis and biological evaluation of mixed-ligand cyclometalated iridium(III)-quinoline complexes.

With the aim of gaining new insight into the underlying apoptosis mechanisms and efficacy of cyclometalated Ir(III) complexes as metalodrugs, six new cyclometalated Ir(III)-quinoline complexes, [Ir(1a)(2pq)] (2a), [Ir(1b)(2pq)] (2b), [Ir(1c)(2pq)] (2c), [Ir(1d)(2pq)] (2d), [Ir(1e)(2pq)] (2e), and [Ir(1f)(2pq)] (2f) (2pq = 2-phenylisoquinoline), have been synthesized using 5,7-dihalo-8-hydroxylquinoline ligands (1a-1f) and [Ir(2pq)Cl] precursors and characterized. Complexes 2a-2f have shown potent anticancer activity against cisplatin-resistant SK-OV-3/DDP and A549/DDP cells (IC = 0.11-1.