A Bipyridyl Quinoline Ruthenium(Ⅱ) Complex as a “Light Switch” for Living Cell Mitochondrial Singlet Oxygen

Visualization of 1O2 in cells is of great significance for revealing the laws of life activities. Although many 1O2 fluorescent probes have been reported, their mechanism of capturing 1O2 has not been innovated. Herein, we report a ruthenium(Ⅱ) bipyridyl complex [Ru(bpy)2L3]PF6 with the ability to specifically identify 1O2 based on a novel mechanism of action. The non-fluorescent [Ru(bpy)2L3]PF6 can be accurately oxidized by 1O2 to generate a fluorescent substance with a large Stokes shift (184 nm). [Ru(bpy)2L3]PF6 was successfully applied for visualizing the generation process of 1O2 in living cells and monitoring the morphological changes of mitochondria during photodamage. Therefore, [Ru(bpy)2L3]PF6 has potential to be a useful molecular probe for analyzing physiological processes related to 1O2 in organisms.