A Probe Based on a Soft Salt Complex for Ratiometric and Lifetime Imaging of Variations in Intracellular Oxygen Content

In this study, a soft salt complex based probe has been exploited for measuring oxygen content changes in living cells. The zinc(II) complex [Zn(tpy)2]2+(CH3COO–)2 {tpy = 3‐[(2,2′:6′,2′′‐terpyridin)‐4′‐yl]‐9‐hexyl‐9H‐carbazole} was chosen as the cationic component, and the iridium(III) complex [Ir(tpq)2CN2]–Bu4N+ [tpq = 2‐(thiophen‐2‐yl)quinoline] was selected as the anionic component. The soft salt complex based probe was formed through electrostatic interaction between two oppositely charged complexes. This probe exhibits ratiometric photoluminescence response to different oxygen concentrations with two separated emission bands. Furthermore, the application of this probe in ratiometric and lifetime imaging of oxygen content changes in living cells has been demonstrated. A novel soft salt based probe, which consists of a cationic zinc(II) complex and an anionic iridium(III) complex with two distinguishable emission colors, has been developed for the detection of oxygen content variations. Importantly, this soft salt based probe has been successfully utilized for ratiometric and lifetime imaging of intracellular oxygen content alterations.