华南理工大学赵祖金团队报道了通过加强空间共轭作用来增强分子电导的稳定螺旋结构。相关研究成果发表在2024年9月03日出版的《德国应用化学》。

开发具有稳定螺旋结构的长链分子对于理解和调节螺旋生物大分子的性质和功能具有重要意义，但具有挑战性。

该文中，研究人员以新的邻六苯撑（o-HP）衍生物为模型，提出了一种通过空间共轭增强来稳定折叠螺旋结构的有效和简便的方法。实验和理论研究了所制备的折叠螺旋o-HP衍生物的贯穿空间共轭与电荷输运行为之间的构效关系。

研究表明，引入吸电子吡啶和吡嗪可以增强o-HP衍生物内的贯穿空间共轭，从而有效稳定o-HP衍生物的螺旋结构。此外，扫描隧道显微镜断裂结测量表明，o-HP衍生物的稳定规则螺旋结构开辟了主要的空间电荷传输途径，通过与吡啶和吡嗪的空间共轭增强，单分子电导提高了70%以上。但是，通过键电荷传输途径对o-HP衍生物的电导贡献要小得多。

研究结果不仅为探索稳定的螺旋分子提供了一种新方法，而且为在单分子水平上破译和调节螺旋系统的电荷输运行为奠定了基础。

附：英文原文

Title: Towards Stable Helical Structures with Enhanced Molecular Conductance by Strengthening Through-Space Conjugation

Author: Shaoshao Jiao, Pingchuan Shen, Jinshi Li, Xiaobin Dong, Ben Zhong Tang, Zujin Zhao

Issue&Volume: 03 September 2024

Abstract: Developing long-chain molecules with stable helical structures is of significant importance for understanding and modulating the properties and functions of helical biological macromolecules, but challenging. In this work, an effective and facile approach to stabilize folded helical structures by strengthening through-space conjugation is proposed, using new ortho-hexaphenylene (o-HP) derivatives as models. The structure-activity relationship between the through-space conjugation and charge transport behavior of the prepared folded helical o-HP derivatives is experimentally and theoretically investigated. It is demonstrated that the through-space conjugation within o-HP derivatives can be strengthened by introducing electron-withdrawing pyridine and pyrazine, which can effectively stabilize the helical structures of o-HP derivatives. Moreover, scanning tunneling microscopy-break junction measurements reveal that the stable regular helical structures of o-HP derivatives open up dominant through-space charge transport pathways, and the single-molecule conductance is enhanced by more than 70% by strengthening through-space conjugation with pyridine and pyrazine. But the through-bond charge transport pathways contribute much less to the conductance of o-HP derivatives. These results not only provide a new method for exploring stable helical molecules, but also pave a stepping stone for deciphering and modulating the charge transport behavior of helical systems at the single-molecule level.

DOI: 10.1002/anie.202414801

Source: https://onlinelibrary.wiley.com/doi/10.1002/anie.202414801