On-surface synthesis of cyclo[20]carbon and cyclo[30]carbon from cyclo[10]carbon.

Guo, Yuan; Yun, Yuzhe; Xiang, Wenzhi; Xu, Guorui; Sun, Luye; Xu, Wei · Nat Commun · 2025

basic_science · Level V

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Abstract

On-surface synthesis recently enabled access to generate a series of cyclo[n]carbons (C<sub>n</sub>, up to C<sub>26</sub>) via delicately designed precursors. However, for larger cyclocarbons, synthesis of the corresponding precursors is being challenged. Here, we report another strategy for synthesizing larger cyclocarbons via the coupling and ring-opening reactions from smaller ones. We chose C<sub>10</sub> as the precursor, and induce the coupling and ring-opening reactions via tip manipulation to successfully generate C<sub>20</sub> and C<sub>30</sub>. Bond-resolved atomic force microscopy imaging unambiguously reveals the polyynic structure of C<sub>30</sub>, aligning with theoretical prediction. This approach establishes a new pathway to access larger cyclocarbons, and potentially enables controlled polymerization of cyclocarbons.