Ambient Chemical Fixation of CO2 Using a Robust Ag27 Cluster‐Based Two‐Dimensional Metal–Organic Framework

Abstract Unprecedented double S 2− templated Ag 27 clusters have been stabilized by 5,10,15,20‐tetra(4‐pyridyl)porphyrin (TPyP‐H 2 ) ligands to afford a robust 2D metal–organic framework ( Ag27‐MOF ). This silver cluster‐assembled material serves as a highly efficient heterogeneous catalyst for the cyclization of both terminal and internal propargylamines with CO 2 under atmospheric pressure. Density functional theory (DFT) calculations illustrate that the high catalytic activity and broad substrate scope are attributable to the saddle‐shaped metallic node in Ag27‐MOF , which features an accessible platform with high‐density silver atoms as π‐Lewis acid sites for activating C≡C triple bonds. As a result, different sterically hindered alkyne substrates can be effectively activated through π‐interactions with these cationic silver centers.