近日，日本东北大学Takeaki Iwamoto团队研究了具有非平面6π芳香Si₅环的硅环戊二烯化合物。相关论文于2026年2月5日发表在《科学》杂志上。

与碳基π电子化合物种类繁多的研究报告相比，硅基同类化合物仍然稀少，这源于硅元素本质上更倾向于形成σ键化合物。特别值得注意的是，π电子在五个或更多硅原子间离域的硅化合物长期以来难以获得。

研究组报道了环戊二烯基阴离子的五硅类似物（五硅环戊二烯基化合物）的合成。这些化合物含有非平面五元硅环结构，其中部分硅原子呈锥形化特征，且硅-硅键长不均匀。五硅环戊二烯基锂化合物中高度屏蔽的⁷Li核磁共振信号证实了五元环中存在抗磁环电流，表明该体系至少具备一定程度的芳香性。此外，计算研究表明，大位阻取代基与π电子的离域作用共同稳定了五硅环戊二烯基化合物的结构。

附：英文原文

Title: Silicon cyclopentadienides featuring a nonplanar 6π aromatic Si5 ring

Author: Takeaki Iwamoto, Tomoki Ishikawa, Shintaro Ishida

Issue&Volume: 2026-02-05

Abstract: Compared with the wide variety of reports on carbon π-electron compounds, the silicon counterparts remain scarce because of the intrinsic preference of silicon to form σ-bonded compounds. In particular, silicon compounds in which π-electrons are delocalized over five or more silicon atoms have been elusive. We report the synthesis of pentasilicon analogs of cyclopentadienides (pentasilacyclopentadienides). These compounds contain nonplanar five-membered silicon rings with some pyramidalized silicon atoms and uneven silicon-silicon distances. The highly shielded 7Li nuclear magnetic resonance signal of a lithium pentasilacyclopentadienide corroborates the presence of a diamagnetic ring current in the five-membered ring, which is indicative of at least some degree of aromaticity. Furthermore, a computational study revealed that bulky substituents and the delocalization of π-electrons stabilize the pentasilacyclopentadienide structure.

DOI: aed0168

Source: https://www.science.org/doi/10.1126/science.aed0168