北京大学郭雪峰团队报道了纳米约束下可逆环加成的单电子催化。相关研究成果发表在2025年2月6日出版的《美国化学会杂志》。

电子转移（ET）在许多化学反应中至关重要，但由于所涉及的反应物种和途径的复杂性，其机制和作用在纳米生物技术中很难被理解。通过在单分子水平上调节和监测电子行为，人们可以更好地了解控制它们用于技术用途的基本机制和方法。

该文中，研究人员揭示了带正电的纳米约束下单电子催化的机制。证明了（2+2）和（4+4）环加成反应都可以被一个电子可逆地催化。通过先进的单分子检测平台监测环加成反应中的连续电信号，发现了关键的反应途径。实验和理论结果一致表明，将单一ET过程与涉及葫芦素[8]脲的纳米约束相结合可以降低反应能垒并促进可逆的环加成反应。此外，研究发现偏压可以微调ET过程和键形成和断裂中的化学平衡。

研究结果为阐明、调节和设计涉及电子的反应和功能化装置提供了一种新方法。

附：英文原文

Title: Single-Electron Catalysis of Reversible Cycloadditions under Nanoconfinement

Author: Xin Zhu, Hongliang Chen, Jinying Wang, Agostino Migliore, Xingxing Li, Yanwei Li, Boyu Wang, Chen Yang, Yang Jiao, Jiawen Cao, Caiyao Yang, Chunyan Gao, Suhang He, Kendall N. Houk, Jinlong Yang, J. Fraser Stoddart, Chuancheng Jia, Xuefeng Guo

Issue&Volume: February 6, 2025

Abstract: Electron transfer (ET) is crucial in many chemical reactions, but its mechanism and role are hardly understood in nanobiotechnology due to the complexity of reaction species and pathways involved. By modulating and monitoring electron behavior at the single-molecule level, we can better understand the fundamental mechanisms and ways to control them for technological use. Here, we unravel a mechanism of single-electron catalysis under positively charged nanoconfinement. We demonstrate that both (2 + 2) and (4 + 4) cycloadditions can be catalyzed reversibly by a single electron. Key reaction pathways are discovered by monitoring sequential electrical signals in the cycloadditions through advanced single-molecule detection platforms. Experimental and theoretical results consistently demonstrate that combining single ET processes with nanoconfinement involving cucurbit[8]uril can lower the reaction energy barrier and promote reversible cycloaddition. Moreover, we show that the bias voltage can fine-tune ET processes and chemical equilibria in bond formation and cleavage. Our results provide a novel approach to elucidate, modulate, and design electron-involved reactions and functionalized devices.

DOI: 10.1021/jacs.4c18064

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c18064