We have designed and synthesized two Ir(III) complexes
(
Ir1
and
Ir2
) 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.
Ir1
and
Ir2
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
Ir1
and
Ir2
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.