近日，英国曼彻斯特大学Stephen T. Liddle团队报道了环-Bi₃³⁻在双铀和双钍逆三明治型配合物中的全金属芳香性。2026年4月20日出版的《自然-化学》杂志发表了这项成果。

离域[4n+2]π芳香性在环状平面不饱和有机分子中是有机化学的理论基石。近年来，全金属芳香性的研究蓬勃发展，尽管对环-{E₃}（E = P, As, Sb, Bi）物种作为环丙烯鎓类似物的兴趣日增，但环-{Bi₃}的形成仍然罕见。因此，作为最重的6p环丙烯鎓类似物，2π/6π-环-Bi₃^+/3-的潜在芳香性一直存在不同解读。

研究组报道了双铀和双钍的6π-环-Bi₃³⁻反三明治配合物的合成，这补充了为数不多的非环状和环状Bi_n（n=3–5）化合物。该6π-环-Bi₃³⁻环表现出显著的环电流，类似于6π-苯、2π-(C₃H₃)⁺或6π-(C₃H₃)^3-。计算表明，6π-环-Bi₃³⁻、2π-环-Bi₃⁺和0π-环-Bi₃³⁺具有相似的环电流，显示出σ芳香性在环-Bi₃³⁻中占据主导地位，尽管用定域键而非离域键描述环-Bi₃³⁻更为合适。6π-环-Bi₃³⁻的σ芳香性的确认为π芳香性(C₃H₃)^+/3-提供了最重的全金属6p类似物，从而建立了有机-无机芳香性基准。

附：英文原文

Title: All-metal aromaticity of cyclo-Bi33 in diuranium and dithorium inverse-sandwich-type complexes

Author: Ding, Junru, Seed, John A., Beuthert, Katrin, Peerless, Benjamin, Rienmller, Julia, Schmidt, Andreas, Wooles, Ashley J., Natrajan, Louise S., Chen, Chuan-Ling, Sun, Zhong-Ming, Weigend, Florian, Dehnen, Stefanie, Du, Jingzhen, Liddle, Stephen T.

Issue&Volume: 2026-04-20

Abstract: Delocalized [4n+2]π-aromaticity in cyclic planar unsaturated organic molecules conceptually underpins organic chemistry. Recently, the study of all-metal aromaticity has burgeoned, but although there has been interest in cyclo-{E3} (E=P, As, Sb, Bi) species as cyclopropenium analogues, the formation of cyclo-{Bi3} remains rare. Thus, the potential aromaticity of 2/6π-cyclo-Bi3+/3, as the heaviest 6p analogue of cyclopropylium, has remained open to different interpretations. Here we report the formation of diuranium and dithorium 6π-cyclo-Bi33 inverse sandwich complexes, complementing the small number of acyclic- and cyclic-Bin (n=3–5) compounds. The 6π-cyclo-Bi33 ring exhibits substantial ring currents, similar to 6π-benzene, 2π-(C3H3)+ or 6π-(C3H3)3. Calculations reveal similar ring currents for 6π-cyclo-Bi33, 2π-cyclo-Bi3+ and 0π-cyclo-Bi33+, demonstrating σ-aromaticity that is dominant over π-aromaticity in cyclo-Bi33, despite the favourability of describing cyclo-Bi33 with localized rather than delocalized bond descriptions. Confirmation of 6π-cyclo-Bi33 σ-aromaticity provides the heaviest all-metal 6p analogue to π-aromatic (C3H3)+/3, leading to organic–inorganic aromaticity benchmarking.

DOI: 10.1038/s41557-026-02123-8

Source: https://www.nature.com/articles/s41557-026-02123-8