Ru Cluster-Decorated Cu Nanoparticles Enhanced Selectivity to Imine from One-Pot Cascade Transformations

One-pot cascade transformations are environmentally friendly and are used to prepare complex organic molecules. However, chemselectivity is hard to control during the tandem reaction of imines. Herein, a Cu nanoparticle-decorated Ru cluster catalyst (Cu6Ru1.5/C-SiO2), with an average size of 2.1 nm, was designed and synthesized by impregnation and galvanic replacement. The synergistic effect of the Ru cluster and Cu nanoparticles caused Cu6Ru1.5/C-SiO2 to carry more Lewis acid active sites and constituted a unique catalyst surface. Then, the hydrogenation of nitrobenzene and reductive amination of benzaldehyde were effectively performed during a one-pot cascade transformation on the surface of the catalyst. Finally, N-benzylidene aniline (imine) was prepared smoothly by nitrobenzene and benzaldehyde with 96.3% selectivity in this catalytic system. This work provides a general and powerful strategy to optimize the catalytic performance, which can be scalable to other catalytic systems.