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

Liu, Shengnan; Han, Jiahong; Wang, Weijin; Chang, Yulei; Wang, Runlin; Wang, Ziwei; Li, Guangzhe; Zhu, Dongxia; Bryce, Martin R.

Abstract

Photodynamic therapy (PDT) is a promising cancer treatment method. Traditional small-molecule photosensitizers (PSs) suffer from low intersystem crossing (ISC) ability and aggregation-caused quenching (ACQ), which adversely affects the luminous efficiency and singlet oxygen (1O2) yield of PSs in the aggregated state. Ir(III) complexes are promising PSs with long excited-state lifetime, good photophysical and photochemical properties and large Stokes shifts. Aggregation-induced emission (AIE) characteristics could reduce the nonradiative recombination and improve the ISC ability of excited states through the restriction of the intramolecular motions in aggregated states. Accordingly, two AIE-active Ir(III) complexes Ir-1-N+ and Ir-2-N+ were successfully designed and obtained based on Schiff base ligands. Experimental results showed that Ir-1-N+ and Ir-2-N+ have good photophysical properties and the corresponding nanoparticles (NPs) have good water solubility and 1O2 generation ability. Notably, Ir-2-N+ NPs can be efficiently taken up by mouse breast cancer cells (4T1 cells) with good biocompatibility, low dark toxicity and excellent phototoxicity. This work demonstrates a versatile strategy for exploiting efficient transition metal PSs with a cationic ligand in PDT.

Citation

Liu, S., Han, J., Wang, W., Chang, Y., Wang, R., Wang, Z., Li, G., Zhu, D., & Bryce, M. R. (2022). AIE-active Ir(iii) complexes functionalised with a cationic Schiff base ligand: synthesis, photophysical properties and applications in photodynamic therapy. Dalton Transactions, 51(42), 16119-16125. https://doi.org/10.1039/d2dt02960j

• Journal Article Type: Article
• Acceptance Date: Sep 30, 2022
• Online Publication Date: Oct 11, 2022
• Publication Date: 2022
• Deposit Date: Jan 9, 2023
• Publicly Available Date: Jan 9, 2023
• Journal: Dalton Transactions
• Print ISSN: 1477-9226
• Electronic ISSN: 1477-9234
• Publisher: Royal Society of Chemistry
• Peer Reviewed: Peer Reviewed
• Volume: 51
• Issue: 42
• Pages: 16119-16125
• DOI: https://doi.org/10.1039/d2dt02960j
• Public URL: https://durham-repository.worktribe.com/output/1183376