Optical modulation of Iridium(III) complexes for enhanced ROS generation: Multi-photon absorption and near-infrared photodynamic therapy insights

In this study, we harness optical modulation techniques to tailor an auxiliary ligand, thereby optimizing the photophysical behavior of cyclometalated iridium (III) complexes, Ir-B and Ir-Q, for enhanced reactive oxygen species (ROS) generation. Intriguingly, the optical properties of Ir-Q's auxiliary ligands instigate a non-radiative intersystem crossover process, yielding a superior singlet oxygen (1O2) quantum efficiency of 0.92. Further, Ir-Q's robust multi-photon absorption spectra, particularly in the Two-photon (750-800 nm) and Three-photon (1350-1600 nm) domains, open avenues for potential applications in two-photon imaging-guided photodynamic therapy targeting deep-seated tumors. This investigation underscores the pivotal role of optical structure modulation in amplifying the therapeutic potential of the iridium(III) complex, particularly in the realm of near-infrared photodynamic therapy.

Automated summary

This study utilizes optical modulation techniques to optimize the photophysical behavior of cyclometalated iridium(III) complexes by tailoring the auxiliary ligand for enhanced reactive oxygen species generation. One of the complexes, Ir-Q, exhibits superior singlet oxygen quantum efficiency of 0.92 due to the non-radiative intersystem crossover process initiated by its auxiliary ligand's optical properties. Furthermore, Ir-Q's robust multi-photon absorption spectra in the two-photon and three-photon domains offer potential applications in two-photon imaging-guided photodynamic therapy for deep-seated tumors.