Reforming sustainable 3d-metal-based visible light catalytic platforms for inert bulk chemical activation is highly desirable. Herein, we demonstrate the use of a Brønsted acid to unlock robust and practical iron ligand-to-metal charge transfer (LMCT) photocatalysis for the activation of multifarious inert haloalkylcarboxylates (C_nX_mCOO⁻, X = F or Cl) to produce C_nX_m radicals. This process enables the fluoro-polyhaloalkylation of non-activated alkenes by combining easily available Selectfluor as a fluorine source. Valuable alkyl fluorides including potential drug molecules can be easily obtained through this protocol. Mechanistic studies indicate that the real light-harvesting species may derive from the in situ-assembly of Fe³⁺, C_nX_mCOO⁻, H⁺, and acetonitrile solvent, in which the Brønsted acid indeed increases the efficiency of LMCT between the iron center and C_nX_mCOO⁻ via hydrogen-bond interactions. We anticipate that this Brønsted acid-unlocked iron LMCT platform would be an intriguing sustainable option to execute the activation of inert compounds.

改革可持续的基于 3D 金属的可见光催化平台以实现惰性本体化学活化是非常必要的。在此，我们演示了使用布朗斯台德酸来解锁强大且实用的铁配体到金属电荷转移（LMCT）光催化，以激活多种惰性卤代烷基羧酸盐（C _n X _m COO ^- ，X = F或Cl）以产生C _n X _m自由基。该工艺通过结合容易获得的 Selectflu 作为氟源，实现非活化烯烃的氟多卤烷基化。通过该方案可以轻松获得包括潜在药物分子在内的有价值的烷基氟化物。机理研究表明，真正的光捕获物种可能来源于 Fe ³⁺ 、C _n X _m COO ⁻ 、H ⁺和乙腈溶剂的原位组装，其中 Brønsted 酸确实提高了 LMCT 之间的效率。铁中心和 C _n X _m COO ⁻通过氢键相互作用。我们预计，这种 Brønsted 酸解锁铁 LMCT 平台将成为执行惰性化合物活化的一个有趣的可持续选择。