Department of Chemistry, UiT - The Arctic University of Norway, N-9037, Tromsø, Norway.
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, 94720-8229, United States.
Sci Rep. 2020 May 5;10(1):7551. doi: 10.1038/s41598-020-64389-3.
Six-coordinate iridium(III) triarylcorrole derivatives, Ir[TpXPC)]L, where TpXPC = tris(para-X-phenyl)corrole (X = CF, H, Me, and OCH) and L = pyridine (py), trimethylamine (tma), isoquinoline (isoq), 4-dimethylaminopyridine (dmap), and 4-picolinic acid (4pa), have been examined, with a view to identifying axial ligands most conducive to near-infrared phosphorescence. Disappointingly, the phosphorescence quantum yield invariably turned out to be very low, about 0.02 - 0.04% at ambient temperature, with about a two-fold increase at 77 K. Phosphorescence decay times were found to be around ~5 µs at 295 K and ~10 µs at 77 K. Fortunately, two of the Ir[TpCFPC)]L derivatives, which were tested for their ability to sensitize singlet oxygen formation, were found to do so efficiently with quantum yields Φ(O) = 0.71 and 0.38 for L = py and 4pa, respectively. Iridium corroles thus may hold promise as photosensitizers in photodynamic therapy (PDT). The possibility of varying the axial ligand and of attaching biotargeting groups at the axial positions makes iridium corroles particularly exciting as PDT drug candidates.
六配位铱（III）三芳基卟啉衍生物 Ir[TpXPC)]L，其中 TpXPC = 三（对 -X- 苯基）卟啉（X = CF、H、Me 和 OCH），L = 吡啶（py）、三甲胺（tma）、异喹啉（isoq）、4-二甲氨基吡啶（dmap）和 4-吡啶甲酸（4pa），已被研究，旨在确定最有利于近红外磷光的轴向配体。令人失望的是，磷光量子产率始终非常低，在环境温度下约为 0.02-0.04%，在 77 K 时约增加两倍。在 295 K 时，磷光衰减时间约为5 µs，在 77 K 时约为10 µs。幸运的是，两种 Ir[TpCFPC)]L 衍生物被测试了它们敏化单线态氧形成的能力，发现 L = py 和 4pa 时，量子产率 Φ(O)分别为 0.71 和 0.38。因此，铱卟啉可能有希望成为光动力疗法（PDT）中的光敏剂。通过改变轴向配体和在轴向位置连接生物靶向基团的可能性，使铱卟啉作为 PDT 药物候选物特别令人兴奋。
