A Lanthanide‐Complex‐Based Ratiometric Luminescent Probe Specific for Peroxynitrite

A lanthanide‐complex‐based ratiometric luminescence probe specific for peroxynitrite (ONOO^?), 4′‐(2,4‐dimethoxyphenyl)‐2,2′:6′,2′′‐terpyridine‐6,6′′‐diyl]bis(methylenenitrilo)tetrakis(acetate)‐Eu³⁺/Tb³⁺ (Eu³⁺/Tb³⁺(DTTA)]), has been designed and synthesized. Both Eu³⁺(DTTA)] and Tb³⁺(DTTA)] are highly water soluble with large stability constants at ≈10²⁰, and strongly luminescent with luminescence quantum yields of 10.0 and 9.9 %, respectively, and long luminescence lifetimes of 1.38 and 0.26 ms, respectively. It was found that the luminescence of Tb³⁺(DTTA)] could be quenched by ONOO^? rapidly and specifically in aqueous buffers, while that of Eu³⁺(DTTA)] did not respond to the addition of ONOO^?. Thus, by simply mixing Eu³⁺(DTTA)] and Tb³⁺(DTTA)] in an aqueous buffer, a ratiometric luminescence probe specific for time‐gated luminescence detection of ONOO^? was obtained. The performance of Tb³⁺(DTTA)] and Eu³⁺/Tb³⁺(DTTA)] as the probes for luminescence imaging detection of ONOO^? in living cells was investigated. The results demonstrated the efficacy and advantages of the new ratiometric luminescence probe for highly sensitive luminescence bioimaging application.