Synergetic roles of pyridinic nitrogen and carbonyl sites in nitrogen-doped carbon for the metal-free transfer hydrogenation reactions

Transition metal catalysts are commonly used for chemical reactions, especially for transfer hydrogenation reactions. From the viewpoints of green and sustainable chemistry, it is highly demanded to develop metal-free catalytic systems. Herein, oxygen-containing groups modified nitrogen-doped carbon catalysts were discovered to be robust for the transfer hydrogenation reaction between nitroarenes and saturated N-heterocyclic compounds, achieving high yields of anilines and unsaturated N-heterocyclic. Control experiments and characterization results indicate that pyridinic N and carbonyl groups are the active sites. Furthermore, DFT calculation indicate that pyridinic N serves the role in the capture of the H atom from the N−H site in N-heterocycles and carbonyl group assists to capture the H atom from the adjacent carbon site. The as-formed H• species are then transferred to nitro groups in nitroarenes to generate anilines. This amalgamation of multiple active sites reveals opportunities for developing modified metal-free carbon catalysts for extensive applications.