Unshielded Ino Decahedral Core Copper Nanoclusters Enable Efficient Photocatalytic Sulfonylation of Aryl Halides

The synthesis of metal nanoclusters (NCs) having decahedral cores is challenging, with only a few reports primarily focusing on systems containing gold (Au) and silver (Ag). Herein, we present the synthesis, characterization, and catalytic activities of a copper (Cu) NC featuring a centered Ino decahedral core: Cu₁₉(^tBuPhCH₂S)₁₂(PPh₃)₆H₆Br (Cu₁₉). Unlike typical core-shell structured NCs, Cu₁₉ exhibits a unique structure with a core capped by four motifs from four directions, where two square faces and both apexes of the Ino decahedron core are capped, leaving three square faces of the core exposed, acting as highly efficient catalytic active sites. This distinctive design opens new possibilities for catalytic applications of Cu NCs, as demonstrated experimentally in the sulfonylation of aryl halides under visible light irradiation at room temperature. Density functional theory (DFT) and experimental results suggest that the catalytic cycle proceeds through a single-electron transfer (SET) process between the photoexcited Cu₁₉ NC-sulfinates and the aryl halide, enabling efficient C-S arylation of sulfinates. The unshielded Cu₁₉ NC catalysts can be converted into a heterogeneous recyclable catalyst and are compatible with a wide range of aryl halides and sulfinate nucleophiles for producing sulfones.