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

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 m...

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Main Authors: Deng-Yuan Li, Zheng-Yang Huang, Li-Xia Kang, Bing-Xin Wang, Jian-Hui Fu, Ying Wang, Guang-Yan Xing, Yan Zhao, Xin-Yu Zhang, Pei-Nian Liu
Format: Article
Language:English
Published: Nature Portfolio 2024-11-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-024-53927-6
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Summary: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.
ISSN:2041-1723