Recent Progresses in On‐Surface Glaser Coupling

On‐surface synthesis offers robust and versatile routes for fabricating atomically precise carbon‐rich nanomaterials through the transformation of covalent coupling reactions from solution to two‐dimensional confined interfaces. The dehydrogenative homocoupling (Glaser coupling) of terminal alkynes and their derivatives provide a direct and efficient pathway to form 1,3‐diyne linkages and molecular hydrogen as the sole byproduct. The linear geometry and high directionality of alkynes enable the bottom‐up construction of extended low‐dimensional carbon frameworks with high structural regularity. The process exhibits broad substrate compatibility from catalytically active coinage metal surfaces to electronically inert insulating surfaces. The interactions between precursor and surface template dictate product selectivity, orientation, and long‐range order. Nevertheless, competing pathways such as enyne formation, cyclotrimerization, and radical rearrangements exist along with the Glaser coupling. And the surface‐dependent reactivity, chemical group functionality influence, steric effect, and external stimuli (e.g., light, H 2 O or O 2 coadsorption, and Cu 2+ additives) can steer the selectivity toward Glaser coupling. Recent mechanistic insights by SPM and DFT simulations reveal transient intermediates, hydrogen‐transfer steps, and Glaser‐type dimers, clarifying the coupling pathway. This article comprehensively discusses the breakthroughs in the formation of atomically precise diyne‐linked nanostructures via Glaser coupling of alkynes.