AIE-active Ir(iii) complexes functionalised with a cationic Schiff base ligand: synthesis, photophysical properties and applications in photodynamic therapy

Abstract

Two AIE-active Ir(iii) cationic complexes containing Schiff base ligands were synthesised. Ir-2-N+ NPs are shown to be good PSs in vitro for PDT.

Rational Molecular Designing of Aggregation-Enhanced Emission (AEE) Active Red-Emitting Iridium(III) Complexes: Effect of Lipophilicity and Nanoparticle Encapsulation on Photodynamic Therapy Efficacy

“…49 with excited-state lifetimes of 542 and 551 ns, respectively. 50 Here, the synthesized SM4 results in a microsecond range (0.81 μs) lifetime, indicating a significant improvement in the lifetime compared to previously reported compounds (Figure S18, ESI).…”

“…In a previous study, Li et al reported the AIE active iridium­(III) based PS1 and PS3 along with their NPs with lifetimes of 54 and 24 ns for PS1 and PS3, whereas the lifetimes of PS1 NPs and PS3 NPs are 63 and 32 ns, respectively . In 2022, Liu et al reported Ir-1-N + and Ir-2-N + with excited-state lifetimes of 542 and 551 ns, respectively . Here, the synthesized SM4 results in a microsecond range (0.81 μs) lifetime, indicating a significant improvement in the lifetime compared to previously reported compounds (Figure S18, ESI).…”

“…Light at a wavelength of 450 nm and an intensity of 20 mW cm –2 was utilized by Zhang et al for PDT for 30 min . In 2022, Liu et al employed a light source with a wavelength of 425 nm and an intensity of 20 mW cm –2 for 30 min for PDT . Li et al also used a light source of 450 nm of power 20 mW cm –2 for 30 min for PDT .…”

“…22 In 2022, Liu et al employed a light source with a wavelength of 425 nm and an intensity of 20 mW cm −2 for 30 min for PDT. 50 Li et al also used a light source of 450 nm of power 20 mW cm −2 for 30 min for PDT. 49 Depending upon the maximum absorption coefficient for SM4, we used a 468 nm light source of intensity 50 mW cm −2 for 10 min only.…”

Near-infrared AIE-active phosphorescent iridium(iii) complex for mitochondria-targeted photodynamic therapy

“…The fluorescence of PSs with aggregation-induced emission (AIE) properties is enhanced under the aggregation state, which could well solve the difficulties of traditional PSs in the clinical application of image-guided PDT. [30][31][32][33] Mitochondria-targeted metal-based PSs have been widely reported by many research groups, but their development is greatly limited due to the short irradiation wavelengths, which are generally less than 500 nm, severe photodamage, and low penetration depth. [34][35][36] It is well known that phosphorescent complexes with near-infrared (NIR) emission can not only increase the penetration depth of excitation light to biological tissue but also effectively avoid the interference of self-fluorescence of living tissue in vivo optical imaging.…”