Homogeneous catalysis and heterogeneous separation: Ionic liquids as recyclable photocatalysts for hydroacylation of olefins

The photoinduced ligand-to-metal charge transfer (LMCT) process has been extensively investigated, however, the recovery of photocatalysts has remained a persistent challenge in the field. In light of this issue, a novel approach involving the development of iron-based ionic liquids as photocatalysts has been pursued for the first time, with the goal of simultaneously facilitating the LMCT process and addressing the issue of photocatalyst recovery. Remarkably, the iron-based ionic liquid 1‑butyl‑3-methylimidazolium tetrachloroferrate (C₄mim-FeCl₄) demonstrates exceptional recyclability and stability for the photocatalytic hydroacylation of olefins. This study will pave the way for new approaches to photocatalytic organic synthesis using ionic liquids as recyclable photocatalysts.