pH-Responsive N^C-cyclometalated iridium(III) complexes: Synthesis, photophysical properties, computational results, and bioimaging application

Результат исследований: Научные публикации в периодических изданияхстатьярецензирование

Аннотация

Herein we report four [Ir(N^C)2(L^L)]n+, n = 0,1 complexes (1–4) containing cyclometal-lated N^C ligand (N^CH = 1-phenyl-2-(4-(pyridin-2-yl)phenyl)-1H-phenanthro[9,10-d]imidazole) and various bidentate L^L ligands (picolinic acid (1), 2,2′-bipyridine (2), [2,2′-bipyridine]-4,4′-dicar-boxylic acid (3), and sodium 4,4′,4″,4‴-(1,2-phenylenebis(phosphanetriyl))tetrabenzenesulfonate (4). The N^CH ligand precursor and iridium complexes 1–4 were synthesized in good yield and characterized using chemical analysis, ESI mass spectrometry, and NMR spectroscopy. The solid-state structure of 2 was also determined by XRD analysis. The complexes display moderate to strong phosphorescence in the 550–670 nm range with the quantum yields up to 30% and lifetimes of the excited state up to 60 µs in deoxygenated solution. Emission properties of 1–4 and N^CH are strongly pH-dependent to give considerable variations in excitation and emission profiles accom-panied by changes in emission efficiency and dynamics of the excited state. Density functional theory (DFT) and time-dependent density functional theory (TD DFT) calculations made it possible to assign the nature of emissive excited states in both deprotonated and protonated forms of these molecules. The complexes 3 and 4 internalize into living CHO-K1 cells, localize in cytoplasmic ves-icles, primarily in lysosomes and acidified endosomes, and demonstrate relatively low toxicity, showing more than 80% cells viability up to the concentration of 10 µM after 24 h incubation. Phosphorescence lifetime imaging microscopy (PLIM) experiments in these cells display lifetime distri-bution, the conversion of which into pH values using calibration curves gives the magnitudes of this parameter compatible with the physiologically relevant interval of the cell compartments pH.

Язык оригиналаанглийский
Номер статьи232
ЖурналMolecules
Том27
Номер выпуска1
Ранняя дата в режиме онлайндек 2021
DOI
СостояниеОпубликовано - 1 янв 2022

Предметные области Scopus

  • Аналитическая химия
  • Химия (разное)
  • Молекулярная медицина
  • Фармация
  • Поиск новых лекарств
  • Физическая и теоретическая химия
  • Органическая химия

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