Responsive β-Diketonate-europium(III) Complex-Based Probe for Time-Gated Luminescence Detection and Imaging of Hydrogen Sulfide and .

As a crucial biological gasotransmitter, hydrogen sulfide (HS) plays important roles in many pathological and physiological processes. Highly selective and sensitive detection of HS is significant for the precise diagnosis and evaluation of diverse diseases. Nevertheless, challenges remain in view of the interference of autofluorescence in organisms and the stronger reactivity of HS itself. Herein, we report the design and synthesis of a novel HS-responsive β-diketonate-europium(III) complex-based probe, [Eu(DNB-Npketo)(terpy)], for background-free time-gated luminescence (TGL) detection and imaging of HS in autofluorescence-rich biological samples. The probe, consisting of a 2,4-dinitrobenzenesulfonyl (DNB) group coupled to a β-diketonate-europium(III) complex, shows almost no luminescence owing to the existence of intramolecular photoinduced electron transfer. The cleavage of the DNB group by a HS-triggered reaction results in the recovery of the long-lived luminescence of the Eu complex, allowing the detection of HS in complicated biological samples to be performed in TGL mode. The probe showed a fast response, high specificity, and high sensitivity toward HS, which enabled it to be successfully used for the quantitative TGL detection of HS in tissue homogenates of mouse organs. Additionally, the low cytotoxicity of the probe allowed it to be further used for the TGL imaging of HS in living cells and mice under different stimuli. All of the results suggested the potential of the probe for the investigation and diagnosis of HS-related diseases.