日本北海道大学Ishigaki, Yusuke研究团队报道了碳碳单电子σ键的直接证据。相关研究成果发表在2024年9月25日出版的《自然》。

共价键在两个原子之间共享电子对，并构成大多数有机化合物单键、双键和三键的骨架。相比之下，单电子键的例子仍然很少，很可能是由于它们固有的弱点。尽管一些开创性的研究报告了杂原子之间的单电子键，但碳原子之间单电子键的直接证据仍然难以捉摸。

该文中，研究人员报告了通过具有细长C-C单键的烃的单电子氧化来分离碳原子之间具有单电子σ键的化合物。通过单晶X射线衍射分析和拉曼光谱，以及密度泛函理论计算，实验证实了C-C单电子σ键（在100K下为2.921（3））的存在。

研究结果明确地证明了近一个世纪前提出的C-C单电子σ键的存在，因此可以通过探索键合态和非键合态之间的边界，为化学不同领域的进一步发展铺平道路。

附：英文原文

Title: Direct evidence for a carbon–carbon one-electron σ-bond

Author: Shimajiri, Takuya, Kawaguchi, Soki, Suzuki, Takanori, Ishigaki, Yusuke

Issue&Volume: 2024-09-25

Abstract: Covalent bonds share electron pairs between two atoms and make up the skeletons of most organic compounds in single, double and triple bonds. In contrast, examples of one-electron bonds remain scarce, most probably due to their intrinsic weakness1,2,3,4. Although several pioneering studies have reported one-electron bonds between heteroatoms, direct evidence for one-electron bonds between carbon atoms remains elusive. Here we report the isolation of a compound with a one-electron σ-bond between carbon atoms by means of the one-electron oxidation of a hydrocarbon with an elongated C–C single bond5,6. The presence of the CC one-electron σ-bond (2.921(3) at 100K) was confirmed experimentally by single-crystal X-ray diffraction analysis and Raman spectroscopy, and theoretically by density functional theory calculations. The results of this paper unequivocally demonstrate the existence of a CC one-electron σ-bond, which was postulated nearly a century ago7, and can thus be expected to pave the way for further development in different areas of chemistry by probing the boundary between bonded and non-bonded states.

DOI: 10.1038/s41586-024-07965-1

Source: https://www.nature.com/articles/s41586-024-07965-1