H 2 O 2 -Responsive Organochalcogen-Based Probes for 19 F Chemical Shift-Switching MRI

Hydrogen peroxide (H 2 O 2 ), a key reactive oxygen species, is overexpressed in metabolically dysregulated cells and involved in various disease processes. Herein, we present a class of organochalcogen-based complexes that serve as 19 F MRI probes for H 2 O 2 detection by exhibiting large 19 F chemical-shift changes upon oxidation. Designed probes based on trifluoromethylselenide (CF 3 Se – ) and trifluoromethyltelluride (CF 3 Te – ) react rapidly with H 2 O 2 under mild reaction conditions. The corresponding 19 F chemical-shift changes reach up to 28 and 55 ppm, respectively, under our experimental settings. These substantial shift ranges enable 19 F chemical-shift-switching MRI to specifically visualize H 2 O 2 -rich regions. Notably, the 19 F MRI results of the Se-based analogue demonstrate that a detectable chemical-shift range can be achieved at biologically relevant H 2 O 2 concentrations in a living mouse model of hind limb inflammation. This proof-of-concept study highlights the feasibility of constructing a visual imaging platform using organochalcogen-based 19 F MRI probes with large chemical-shift responsiveness.