A supramolecular dual-lock strategy for retarding prompt back electron transfer
- 1School of Physics and Materials Science, Guangzhou University Guangzhou 510006 China
- 2Henan Key Laboratory of Infrared Materials and Spectrum Measures and Applications, School of Physics, Henan Normal University Xinxiang 453007 China
Abstract
Prompt back electron transfer (BET) limits the lifetime and chemical utility of photogenerated radical pairs in solution. While proton-coupled electron transfer (PCET) can alter the recombination coordinate, effective proton-coupled stabilization requires simultaneous control of electron-transfer energetics, proton-transfer geometry, and radical-pair recombination. Here, we introduce a supramolecular “dual-lock” strategy distributing redox and proton-transfer functions across two molecular components. As a proof of principle, acridine (Acr) and citrazinic acid (CAH) self-assemble through ground-state proton transfer and ion pairing into supramolecular assemblies containing locally H-type-coupled CAH-derived domains. Photoexcitation generates an AcrH˙2+-containing radical-ion pair, and a persistent transient accumulates only in the CAH-rich assembled regime. Assembly-dependent stabilization of this radical pair provides a “spatial lock” against prompt BET. An approximately 190 ps aggregate-associated relaxation may involve charge distribution, whereas a later 970 ps conversion contains a substantial solvent-friction-sensitive contribution together with residual isotope sensitivity and is most consistent with proton transfer coupled to structural reorganization. Together with potential-dependent spectroelectrochemical evolution from AcrH˙2+-like toward Acr˙+-like absorption, these observations support proton transfer to an Acr˙+-containing, proton-reorganized aggregate radical state. The resulting state remains detectable into the sub-microsecond regime. These observations support a kinetic-relay model in which early assembly-dependent stabilization creates the time window required for slower proton-gated stabilization of a charge-separated state.
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BibTeX
@article{xu2026supramolecular,
title = {{A supramolecular dual-lock strategy for retarding prompt back electron transfer}},
author = {Zicheng Xu and Jiangyan Zhou and Jiehao He and Jiashun Xiong and Huiwen Guo and Enyi Lan and Zheng Zhang and Chaochao Qin and Jiawen Fang},
journal = {Chemical Science},
year = {2026},
month = oct,
doi = {10.1039/d6sc05400e},
url = {https://doi.org/10.1039/d6sc05400e},
note = {CC BY-NC 3.0},
}
RIS
TY - JOUR
TI - A supramolecular dual-lock strategy for retarding prompt back electron transfer
AU - Zicheng Xu
AU - Jiangyan Zhou
AU - Jiehao He
AU - Jiashun Xiong
AU - Huiwen Guo
AU - Enyi Lan
AU - Zheng Zhang
AU - Chaochao Qin
AU - Jiawen Fang
PY - 2026
DA - 2026/10/21
JO - Chemical Science
DO - 10.1039/d6sc05400e
UR - https://doi.org/10.1039/d6sc05400e
AB - Prompt back electron transfer (BET) limits the lifetime and chemical utility of photogenerated radical pairs in solution. While proton-coupled electron transfer (PCET) can alter the recombination coordinate, effective proton-coupled stabilization requires simultaneous control of electron-transfer energetics, proton-transfer geometry, and radical-pair recombination. Here, we introduce a supramolecular “dual-lock” strategy distributing redox and proton-transfer functions across two molecular components. As a proof of principle, acridine (Acr) and citrazinic acid (CAH) self-assemble through ground-state proton transfer and ion pairing into supramolecular assemblies containing locally H-type-coupled CAH-derived domains. Photoexcitation generates an AcrH˙2+-containing radical-ion pair, and a persistent transient accumulates only in the CAH-rich assembled regime. Assembly-dependent stabilization of this radical pair provides a “spatial lock” against prompt BET. An approximately 190 ps aggregate-associated relaxation may involve charge distribution, whereas a later 970 ps conversion contains a substantial solvent-friction-sensitive contribution together with residual isotope sensitivity and is most consistent with proton transfer coupled to structural reorganization. Together with potential-dependent spectroelectrochemical evolution from AcrH˙2+-like toward Acr˙+-like absorption, these observations support proton transfer to an Acr˙+-containing, proton-reorganized aggregate radical state. The resulting state remains detectable into the sub-microsecond regime. These observations support a kinetic-relay model in which early assembly-dependent stabilization creates the time window required for slower proton-gated stabilization of a charge-separated state.
SN - 2041-6520
SN - 2041-6539
ER -