Plasmon-driven carbon–fluorine (C(sp ³)–F) bond activation with mechanistic insights into hot-carrier-mediated pathways

The activation of carbon–fluorine bonds is an industrially and environmentally critical, but energetically challenging, transformation. Here we demonstrate a plasmonic photocatalysis approach to visible-light-driven hydrodefluorination that utilizes aluminium–palladium antenna–reactor heterostructures. Photocatalytic hydrodefluorination of aliphatic carbon–fluorine (C(sp³)–F) bonds in fluoromethane as a model molecule, in the presence of deuterium, results in the selective production of monodeuterated methane with a remarkable photocatalytic efficiency and stability. Analysis of the reaction kinetics reveals a reduction in the apparent reaction barrier and changes to the deuterium reaction order under illumination, which suggests a non-thermal contribution from photogenerated hot carriers to the reaction pathway. Using embedded correlated wavefunction methods, the ground- and excited-state energetics and the role of plasmon excitation in lowering the reaction barrier and modifying the kinetics under illumination are determined. Plasmon-mediated carbon–fluorine bond activation represents a promising potential for applications in high-value chemical transformations, as well as in abatement technologies for the mitigation of anthropogenic polyfluoroorganic compounds. [Figure not available: see fulltext.].