An Atomically Precise Copper Cluster Nanoreactor for Efficient Catalysis in Chemical Fixation of Low‐Concentration CO₂

Abstract Chemical fixation of CO 2 with propargylic amines/alcohols into high value‐added fine chemicals represents promising and practical routes for CO 2 resource utilization, but it remains a great challenge to achieve low‐concentration CO 2 conversion in both reactions through one single catalytic system. Herein, a robust copper cluster [(C 6 H 15 NH)(Cu 8 L 8 I)] ( I@Cu 8 ) with nanosized cavities has been constructed. Importantly, the I@Cu 8 cluster as a nanoreactor can efficiently catalyze the chemical conversion of both propargylic amines and propargylic alcohols with CO 2 at simulated flue gas concentrations, due to the unique substrate enrichment effect of its well‐defined nanocavities. Catalytic mechanism investigation and DFT calculations illustrate that the excellent catalytic performance originates from the simultaneous activation of alkynyl (─C≡CH) bonds and amino/hydroxyl (─NHR/─OH) groups in the I@Cu 8 catalytic system, in which the I@Cu 8 ‐substrate intermediates have been confirmed through ESI‐MS analysis. Impressively, this is the first example of a cluster‐based nanoreactor catalyst for low‐concentration CO 2 cyclization reactions with both propargylic amines and propargylic alcohols. This work provides a foundation for the construction of metal cluster‐based catalysts for CO 2 conversion into valuable chemicals.