Unlocking the reducing power of metal nitrides by mechanochemical hydrodefluorination of fluorinated compounds

The carbon-fluorine (C–F) bond, present in both aromatic C(sp2)–F and aliphatic C(sp3)–F moieties, possesses an exceptionally high bond energy. This inherent stability renders C–F bond activation highly challenging. In this work, we address this challenge and reclaim valuable hydrocarbons from fluorinated compounds, including aryl fluorides, alkyl fluorides, and perfluoroalkyl substances, by developing a mechanochemical hydrodefluorination strategy. This approach exploits metal nitrides, particularly magnesium nitride, as reductants, contrasting with previous perception of metal nitrides as merely ammonia surrogates in organic reactions. Remarkably, this mechanochemical protocol achieves the degradation of even persistent polytetrafluoroethylene (Teflon®), a prototypical “forever chemical”. Environmental persistence of organofluorines, stemming from the high bond energy of C–F bonds and resultant chemical inertness, poses substantial environmental safety concerns. Here, the authors reclaim valuable hydrocarbons from fluorinated compounds, including aryl fluorides, alkyl fluorides, and perfluoroalkyl substances, by developing a mechanochemical hydrodefluorination strategy.