A Co^II complex for ¹⁹F MRI-based detection of reactive oxygen species

Abstract

A fluorinated, air-stable cobalt(ii) complex serves as a turn-on ¹⁹F magnetic resonance imaging (MRI) tracer for reactive oxygen species including H₂O₂. Upon oxidation with H₂O₂, the complex converts from paramagnetic high spin Co^II to diamagnetic low spin Co^III resulting in a chemical shift change and enhancement in ¹⁹F NMR signal. Further, the oxidation can be reversed in the presence of reductant Na₂S₂O₄. The turn-on response is demonstrated by ¹⁹F MRI, characterized by a ∼2-3 fold enhancement in signal.