On-surface reactions are a powerful method for constructing nanocarbon materials by forming C–C bonds between small molecules, but the reverse reaction, namely the cleavage of C–C bonds, has been challenging. In this study, we succeeded in systematically decomposing molecular chains synthesized via the Ullmann reaction on Au(111) surfaces into individual units. By combining scanning tunneling microscopy and density functional theory calculations to investigate the decomposition mechanism, we found that the energy barrier for cleaving the C–C bond between units is greatly reduced by a Diels–Alder reaction occurring between adjacent anthracene groups. This work thus provides a novel on-surface synthetic method for disassembling molecular chains.

Created at: 2025-10-16 03:09:08 +0900 Updated at: 2026-09-28 05:54:47 +0900