Work

Room-temperature selective cyclodehydrogenation on Au(111) via radical addition of open-shell resonance structures

Year: 2024

Type: article

Abstract: Cyclodehydrogenation is an important ring-formation reaction that can directly produce planar-conjugated carbon-based nanomaterials from nonplanar molecules. However, inherently high C–H bond energy necessitates a high temperature during dehydrogenation, and the ubiquity of C − H bonds in molecules and small differences in their bond energies hinder the selectivity of dehydrogenation. Here, we report a room-temperature cyclodehydrogenation reaction on Au(111) via radical addition of open-shell resonance structures and demonstrate that radical addition significantly decreases cyclodehydrogenation temperature and further improves the chemoselectivity of dehydrogenation. Using scanning tunneling microscopy and non-contact atomic force microscopy, we visualize the cascade reaction process involved in cyclodehydrogenation and determine atomic structures and molecular orbitals of the planar acetylene-linked oxa-nanographene products. The nonplanar intermediates observed during progression annealing, combined with density functional theory calculations, suggest that room-temperature cyclodehydrogenation involves the formation of transient radicals, intramolecular radical addition, and hydrogen elimination; and that the high chemoselectivity of cyclodehydrogenation arises from the reversibility and different thermodynamics of radical addition step. Cyclodehydrogenation is an important ring-formation reaction but the inherently high C–H bond energy necessitates high temperatures, and the ubiquity of C − H bonds in molecules hinders the selectivity. Here, the authors report a selective room-temperature cyclodehydrogenation reaction on Au(111) via radical addition of open-shell resonance structures.

Source: Nature Communications

DOI: 10.1038/s41467-024-53927-6