Premium
Synthesis and Characterization of Ru(II) Complexes with π‐Expansive Imidazophen Ligands for the Photokilling of Human Melanoma Cells
Author(s) -
Ghosh Goutam,
Yin Huimin,
Monro Susan M.A.,
Sainuddin Tariq,
Lapoot Lloyd,
Greer Alexander,
McFarland Sherri A.
Publication year - 2020
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.13177
Subject(s) - chemistry , ligand (biochemistry) , sodium azide , medicinal chemistry , quantum yield , stereochemistry , photochemistry , phenanthroline , azide , fluorescence , crystallography , receptor , organic chemistry , biochemistry , physics , quantum mechanics
Abstract Ru(II) complexes were synthesized with π‐expanding (phenyl, fluorenyl, phenanthrenyl, naphthalen‐1‐yl, naphthalene‐2‐yl, anthryl and pyrenyl groups) attached at a 1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline ligand and 4,4′‐dimethyl‐2,2′‐bipyridine (4,4′‐dmb) coligands. These Ru(II) complexes were characterized by 1D and 2D NMR, and mass spectroscopy, and studied for visible light and dark toxicity to human malignant melanoma SK‐MEL‐28 cells. In the SK‐MEL‐28 cells, the Ru(II) complexes are highly phototoxic (EC 50 = 0.2–0.5 µ m ) and have low dark toxicity (EC 50 = 58–230 µ m ). The highest phototherapeutic index (PI) of the series was found with the Ru(II) complex bearing the 2‐(pyren‐1‐yl)‐1 H ‐imidazo[4,5‐ f ][1,10]phenanthroline ligand. This high PI is in part attributed to the π‐rich character added by the pyrenyl group, and a possible low‐lying and longer‐lived 3 IL state due to equilibration with the 3 MLCT state. While this pyrenyl Ru(II) complex possessed a relatively high quantum yield for singlet oxygen formation (Φ ∆ = 0.84), contributions from type‐I processes (oxygen radicals and radical ions) are competitive with the type‐II ( 1 O 2 ) process based on effects of added sodium azide and solvent deuteration.