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

Hydrogen peroxide (H₂O₂), 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 ¹⁹F MRI probes for H₂O₂ detection by exhibiting large ¹⁹F chemical-shift changes upon oxidation. Designed probes based on trifluoromethylselenide (CF₃Se⁻) and trifluoromethyltelluride (CF₃Te⁻) react rapidly with H₂O₂ under mild reaction conditions. The corresponding ¹⁹F chemical-shift changes reach up to 28 and 55 ppm, respectively, under our experimental settings. These substantial shift ranges enable ¹⁹F chemical-shift-switching MRI to specifically visualize H₂O₂-rich regions. Notably, the ¹⁹F MRI results of the Se-based analogue demonstrate that a detectable chemical-shift range can be achieved at biologically relevant H₂O₂ 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 ¹⁹F MRI probes with large chemical-shift responsiveness.