Synthesis of pH-responsive cyclometalated iridium() complex and its application in the selective killing of cancerous cells

• Published in: Dalton transactions : an international journal of inorganic chemistry 2021-11, Vol.5 (46), p.17338-17345
• Main Authors: Yang, Peng, Zhang, Shaoqing, Wang, Ke, Qi, Honglan
• Format: Article
• Language: English
• Subjects: Antineoplastic Agents - chemical synthesis; Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; Benzaldehyde; Cell Line; Cell Proliferation - drug effects; Cell Survival - drug effects; Coordination Complexes - chemical synthesis; Coordination Complexes - chemistry; Coordination Complexes - pharmacology; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Emission; Humans; Hydrogen-Ion Concentration; Iridium - chemistry; Iridium - pharmacology; Iridium compounds; Ligands; Photochemotherapy; Photodynamic therapy; Photoluminescence; Photosensitizing Agents - chemical synthesis; Photosensitizing Agents - chemistry; Photosensitizing Agents - pharmacology; Selectivity; Structure-Activity Relationship
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/d1dt03042f

Cyclometalated iridium( iii ) complexes are promising candidates as photosensitizers (PSs) in photodynamic therapy (PDT). The challenge in PDT is the selective killing of cancerous cells over the neighboring normal cells. In this work, a pH-responsive cyclometalated iridium( iii ) complex (probe 1) was designed and synthesized as an effective PS to selectively kill cancerous cells, with 3-(2-pyridyl)benzaldehyde used as the main ligand and 1-(2-pyridyl)-β-carboline used as an ancillary ligand. Probe 1 shows enhanced photoluminescence emission and higher 1 O 2 quantum yield in an acidic environment compared to a neutral solution, which led to remarkable phototoxicity toward cancerous cells and high selectivity for killing cancerous cells over normal cells within 10 min. This work demonstrates that the cyclometalated iridium( iii ) complex with acidic pH-responsive photoluminescence emission and high 1 O 2 generation is an effective alternative PS for selectively killing cancerous cells. The pH-responsive cyclometalated iridium( iii ) complex [(3-pba) 2 Ir(1-Py-βC)]PF 6 was synthesized as an effective photosensitizer for the selective killing of cancerous cells.