南开大学孙忠明的最新研究提出了通过环-Bi5和环-Sb5环合成具有M-M键的三层三明治化合物。该研究于2025年3月18日发表于国际一流学术期刊《自然-化学》杂志上。

本文报道了两个配合物[Cp–V(cyclo-Sb₅)V–Cp]^2-和[ [Cp–Nb(cyclo-Bi₅)Nb–Cp]^2-， [K(18-crown-6)]⁺或[K(2.2.2-crypt)]⁺阳离子在室温和温和条件下稳定。通过各种量子化学方法对它们的成键分析表明，V-V和Nb-Nb键穿过E5环的中心（E = Sb, Nb）。与自由环-E5 （E=Sb,Bi）相比，Cp-E单元之间的环-E5不具有任何芳香特征，因为M-M （M=V,Nb）键穿过环的中心。

研究人员表示，环戊二烯阴离子是一种π芳五元环配体，在有机金属化学中有着广泛的研究课题。用等电子基团15取代环戊二烯中的CH基团，可以得到无机类似物。在这条线中，通过高温反应制备的Pn₅ （Pn=P,Sb）环已经稳定在三层夹层结构中，并且是Bi5在钴基反三明治型配合物中稳定的环已被报道。

附：英文原文

Title: Synthesis of triple-decker sandwich compounds featuring a M–M bond through cyclo-Bi5 and cyclo-Sb5 rings

Author: Xu, Yu-He, Yang, Xing, Yang, Ya-Nan, Zhao, Lili, Frenking, Gernot, Sun, Zhong-Ming

Issue&Volume: 2025-03-18

Abstract: The cyclopentadienyl anion is a π-aromatic five-membered ring ligand that is widely used in organometallic chemistry. By replacing the CH groups in cyclopentadiene with isoelectronic group-15 elements, an inorganic analogue can be obtained. In this line, Pn5 (Pn=P,Sb) rings have been stabilized in a triple-decker sandwich structure, prepared via high-temperature reactions, and an example of a Bi5 ring stabilized in a cobalt-based inverse-sandwich-type complex has been reported. Here we report the synthesis and structural characterization of two complexes, [Cp–V(cyclo-Sb5)V–Cp]2 and [Cp–Nb(cyclo-Bi5)Nb–Cp]2, which are stabilized by [K(18-crown-6)]+ or [K(2.2.2-crypt)]+ cations at room temperature under mild conditions. Our bonding analysis through various quantum-chemical methods reveals that VV and NbNb bonds pass through the centre of the E5 rings (E=Sb,Nb). In contrast to free cyclo-E5 (E=Sb,Bi) the cyclo-E5 moieties between Cp–E units do not possess any aromatic character because the MM (M=V,Nb) bond passes through the centre of the ring.

DOI: 10.1038/s41557-025-01765-4

Source: https://www.nature.com/articles/s41557-025-01765-4