Photogated two conductive pathways of donor-acceptor Stenhouse adducts in single-molecule junctions

Sun, Fanxi and Jiang, Shengqing and Zhang, Hanjun and Wang, Rui and Ji, Yu and Hou, Songjun and Zhang, Maolin and Zhu, Gaolu and Shi, Tianfang and Li, Jiayu and Zheng, Yuantao and Liu, Wenshu and Pan, Yangyang and Luo, Hao and Deng, Xu and Zheng, Yonghao and Wei, Chen and Wang, Dongsheng (2026) Photogated two conductive pathways of donor-acceptor Stenhouse adducts in single-molecule junctions. Nature Communications, 17 (1): 2842. ISSN 2041-1723

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Abstract

Manipulating intramolecular electron transportation can fundamentally modulate the optical property, electromagnetic behavior and chemical reactivity of molecules. Achieving simultaneous control of multiple ( ≥2) transport pathways within a single molecule, however, remains a significant challenge. Herein, we report light-gated modulation of two distinct conductive pathways in single donor-acceptor Stenhouse adduct (DASA) molecules using the scanning tunneling microscopy break-junction (STM-BJ) technique. The donor and π-bridge pathways are separately controlled by designing DASAs with two thiomethyl anchoring sites. In the donor pathway, a side-chain modulation mechanism operates, where linear-to-cyclic isomerization induces electronic redistribution and increases the conductivity. In contrast, the π-bridge pathway is governed by a main-chain modulation mechanism, in which deformation of the π-conjugated backbone decreases the conductivity. By synthesizing DASAs containing three thiomethyl anchoring sites, these two conductive pathways are integrated within a single-molecule junction and can be simultaneously modulated under 635 nm red-light irradiation and dark relaxation. The π-bridge transport in the linear state exhibits mixed through-bond and through-space character, while photoisomerization leads to an increased through-space contribution in the cyclic state driven by cyclopentenone formation. These results highlight DASAs’ potential in understanding molecular electronics and developing photoresponsive molecular-scale devices.