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Title: Synthesis and Characterization of Ru(II) Complexes with π‐Expansive Imidazophen Ligands for the Photokilling of Human Melanoma Cells
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 1H‐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 (EC50 = 0.2–0.5 µm) and have low dark toxicity (EC50 = 58–230 µm). The highest phototherapeutic index (PI) of the series was found with the Ru(II) complex bearing the 2‐(pyren‐1‐yl)‐1H‐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‐lived3IL state due to equilibration with the3MLCT 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 (1O2) process based on effects of added sodium azide and solvent deuteration.

 
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Award ID(s):
1856765
NSF-PAR ID:
10457520
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley-Blackwell
Date Published:
Journal Name:
Photochemistry and Photobiology
Volume:
96
Issue:
2
ISSN:
0031-8655
Page Range / eLocation ID:
p. 349-357
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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