Cyclometalated Ir(III) Complexes as Lysosome-Targeted Photodynamic Anticancer Agents.

We have designed and synthesized two Ir(III) complexes ( and ) coordinated with an 8-sulfonamidoquinoline derivative ligand as photosensitizers, which exhibit strong red phosphorescence emission and a long phosphorescence lifetime. The Ir(III) complexes exhibit a high population of triplet states, which enable red phosphorescence and efficient singlet oxygen generation. and rapidly enter the cancer cells and accumulate in lysosomes, producing large amounts of intracellular singlet oxygen when exposed to light irradiation, eventually leading to cancer cell death, and the phototoxic indexes of complexes and against cancer cells are in the range of 76-228. Overall, our studies indicate that the synthesized Ir(III) complexes with quinoline ligands exhibit photosensitizing properties, effectively inducing cancer cell death when exposed to light. These promising results suggest their potential application in photodynamic therapy.