Room-Temperature Tandem Condensation-Hydrogenation Catalyzed by Porous C3N4 Nanosheet-Supported Pd Nanoparticles

Tandem catalysis, often inspired by biological systems, offers many advantages in the synthesis of highly functionalized small molecules. NH2-grafted porous C3N4 nanosheet with rich N species and surface area of 138 m2/g was fabricated via a NH3-exfoliation method. After supporting Pd nanoparticles, the resulting bifunctional catalyst (Pd/C3N4–NH2) could catalyze a one-step tandem condensation-hydrogenation reaction between ketones and nitriles to form α-alkylated nitriles at room temperature. Under 2 MPa H2 for 8 h, Pd/C3N4–NH2 could afford 99.7% cyclohexanone conversion and 99.8% selectivity without other side reactions, which is much higher than that of bulk C3N4-supported Pd. Compared with commonly used two-step processes, this one-step tandem reaction could largely shorten reaction time and allow condensation-hydrogenation to take place at room temperature. We also found that the hydrogenation step accelerated the condensation step, which increased the overall efficiency of the tandem transformation....