Cu(I)-Anchored Amine-Rich Covalent-Organic Polymer for Sustainable Utilization of CO2 in the Synthesis of Valuable Chemicals and C-C Bond Formation Reactions

Abstract

[EN] Selective chemical fixation of carbon dioxide (CO2) offers a promising approach to mitigate rising atmospheric CO2 levels while facilitating the synthesis of valuable commodity chemicals, thereby supporting the circular economy. The cycloaddition of CO2 to form alpha-alkylidene cyclic carbonates is particularly attractive due to its utilization of CO2, a low-cost C1 feedstock, in a reaction with 100% atom economy. In this study, we have developed an amine-functionalized, nitrogen-rich covalent organic polymer (COP), SNW-1@NH2, which strongly supports the grafting of Cu(I) ions within its porous framework. The synergistic interaction between SNW-1@NH2 and Cu(I) enhances the catalytic activity for the CO2 cycloaddition with propargylic alcohol, resulting in the formation of alpha-alkylidene cyclic carbonates at room temperature without the need for precious metal catalysts. Notably, the catalyst exhibits a broad substrate scope with high recyclability and maintains its structural integrity and catalytic performance. Additionally, the SNW-1@NH2 was successfully applied in the catalytic Knoevenagel condensation of benzaldehyde with cyanoacetamide, demonstrating a broad substrate scope, excellent recyclability, and stability. Mechanistic studies were performed to elucidate the reaction pathways for both catalytic processes. This work underscores the potential of nitrogen-rich porous materials in addressing the critical environmental challenges and expanding catalytic applications.