Establishing Fe-Cu interaction in a novel free-standing material to boost the catalytic activity for ligand-free Suzuki-Miyaura cross-couplings.

[Display omitted] • Ligand-free catalysts consisting of cheap, safe and abundant iron and copper. • The catalyst is convenient to prepare and can be easily recovered. • Broad range of adaptability of the catalyst to the substrate with yields up to 99%, TON up to 9.0 × 103. • The unique electron-donation mechanism enabled the reduction of Cu (Ⅱ) to Cu (Ⅰ) after iron doping, which greatly improved the catalytic activity. In this study, a cheap and easily recyclable "tea-bag" shaped Cu(Fe-Cl)/Al catalyst was fabricated to catalyze the Suzuki-Miyaura coupling reactions with good yields. It was found that, after being doped with iron and chlorine, catalytic activity of the materials was prominently enhanced. The unique electron-donation mechanism enabled the reduction from Cu (Ⅱ) to Cu (Ⅰ) after iron doping, which greatly improved the catalytic activity. An in-depth analysis of the reaction mechanism was then probed using characterizations such as XPS, HRTEM, and control experiments. Compared with traditional homogeneous or heterogeneous metal catalysts, this study can provide a green and economical choice to afford a free-standing recyclable catalyst with extremely high turnover numbers (TON up to 9.1 × 103) for Suzuki cross-coupling reactions. [ABSTRACT FROM AUTHOR]