Tuning Polarity of Cu-O Bond in Heterogeneous Cu Catalyst to Promote Additive-free Hydroboration of Alkynes

Precise control of structural parameters to optimize the performance of heterogeneous catalysts remains a challenging issue. A direct route is to adjust the nature of chemical bonds around active centers, but this has not yet been achieved because of the complexity of heterogeneous catalysts. We utilize an effective strategy to increase the polarity of the Cu-O bond in the ceria-supported, single-atomic-site Cu catalyst for boosting the additive-free hydroboration of alkynes, producing various important vinylboronate compounds. In contrast to the more covalent Cu-O bond, the more ionic Cu-O bond in the catalyst enhances the activity by almost 16-fold. Key intermediate copper ethoxide species preferring to generate on the more ionic Cu-O bond from the dissociation of ethanol results in the improved activity. These results may provide valuable clues for regulating the nature of chemical bonds in heterogeneous catalysts and deepening the understanding of its impact on catalytic behaviors.