Heterogeneous metallaphotocatalytic Cross-Coupling reactions by a carbon Nitride-Nickel catalyst

Abstract

The integration of heterogeneous photocatalysts with nickel catalysis is garnering considerable interest for their capacity to enable distinct metal-photoredox processes for organic synthesis. However, the challenge about robustness and recyclability of the photocatalyst persists. Herein, a crystalline carbon nitride (MCN-B) photocatalyst with intentionally introduced defects and a dedicated designed active site has been presented. Results reveal by incorporating the deprotonated cyano-group (N-–CN) sites, this host material could provide stable binding sites for Ni (II) ions through the Hard-Soft Acid-Base (HSAB) effect, thereby facilitating charge transmission between semiconductor and metal centers. Consequently, the integrated carbon nitride nickel (Ni/MCN-B) heterogeneous photocatalyst demonstrates high effectiveness in diverse photocatalytic C-N coupling reactions (21 examples, up to 93% yield) under conditions free from organic ligands and additives, which shows competent performance to the homogeneous catalysts. Moreover, the Ni/MCN-B catalyst demonstrates remarkable recyclability, maintaining its photoredox efficiency after 10 cycles with minimal loss of activity and a diminished metal leaching rate, which signifies a substantial advancement in the field of photocatalytic system design.