Revealing efficient catalytic performance of N-CuOx for aerobic oxidative coupling of aliphatic alkynes: A Langmuir-Hinshelwood reaction mechanism

Oxidative couplings of aliphatic alkynes are crucial for the production of naturally occurring 1,3-diynes. Herein we report the novel approach for effective synthesis of unsaturated coordinated N doped copper oxides (N-CuOx) catalyst, and uncover that N-CuOx catalyst as an additive-free and cost-effective heterogeneous catalyst has highly catalytic performance for directly oxidative coupling of aliphatic alkynes. The key to achieve efficient oxidative coupling of aliphatic alkynes is the synergistic effect of N species and uncoordinated O/Cu species caused by N dopants, which undergoes the Langmuir-Hinshelwood reaction mechanism. The N-CuOx catalyst displays similar to 89.1% yield for hexadeca-7,9-diyne under mild conditions and stable reusability (5 cycles), showing significant advances compared with the traditionally copper oxides. These findings highlight the heteroatom dopants that provide a new methodology for designing efficient copper catalysts in synthesis of naturally occurring 1,3-diynes.

Automated summary

This study reports a novel approach for the effective synthesis of unsaturated coordinated N-doped copper oxides (N-CuOx) catalyst and demonstrates that N-CuOx catalyst, as an additive-free and cost-effective heterogeneous catalyst, exhibits highly catalytic performance for the direct oxidative coupling of aliphatic alkynes. The key to achieving efficient oxidative coupling of aliphatic alkynes lies in the synergistic effect of N species and uncoordinated O/Cu species caused by N dopants, which follows the Langmuir-Hinshelwood reaction mechanism. The N-CuOx catalyst shows a similar yield of approximately 89.1% for the hexadeca-7,9-diyne under mild conditions and demonstrates stable reusability (5 cycles), displaying significant advancements compared to traditional copper oxides. These findings highlight the importance of heteroatom dopants in the design of efficient copper catalysts for the synthesis of naturally occurring 1,3-diynes.