Thermally and electronically triggered hydrogen shift within a CHCH<sub>2</sub> species via surface-assisted hydrogen tunneling.

Xu, Zhen; Jin, Bin; Zhu, Zhen; Pan, Jinliang; Huang, Zhichao; Di, Bin; Peng, Zhantao; Li, Wentao et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Hydrogen shift along carbon skeletons plays a key role in isomerization and rearrangement reactions in organic synthesis and hydrocarbon catalysis. Here, we demonstrate precise control over hydrogen shift within a bistable CHCH<sub>2</sub> species formed on a Cu(110) surface, using a single-molecule approach via scanning tunneling microscopy. Triggered either thermally or electronically, the hydrogen shift exhibits an apparent activation energy of ≈0.2 eV, which is significantly lower than that of its classical analog of 1.3 eV. In contrast, no corresponding shift is observed in the deuterated CDCD<sub>2</sub> species, revealing a dominant quantum effect behind. This isotopic phenomenon is corroborated by deep-learning-assisted path-integral Monte Carlo simulations which identify a surface-assisted tunneling pathway. Our nanotechnological strategy does lower the activation energy barrier, enabling controllable hydrogen shift for precise molecular synthesis under milder conditions.