Lin Xuhui, Mo Yirong
Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
Department of Nanoscience, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA.
Angew Chem Int Ed Engl. 2022 Sep 12;61(37):e202209658. doi: 10.1002/anie.202209658. Epub 2022 Aug 3.
A unique thorium-thorium bond was observed in the crystalline tri-thorium cluster [{Th(η -C H )(μ -Cl) } {K(THF) } ] , though the claim of σ-aromaticity for Th bond has been questioned. Herein, a new type of core-shell syngenetic bonding model is proposed to describe the stability of this tri-thorium cluster. The model involves a 3c-2e bond in the Th core and a multicentered (ThCl ) charge-shift bond with 12 electrons scattering along the outer shell. To differentiate the strengths of the 3c-2e bond and the charge-shift bond, the block-localized wavefunction (BLW) method which falls into the ab initio valence bond (VB) theory is employed to construct a strictly core/shell localized state and its contributing covalent resonance structure for the Th core bond. By comparing with the σ-aromatic H and nonaromatic Li , the computed resonance energies and extra cyclic resonance energies confirm that this Th core bond is truly delocalized and σ-aromatic.
在晶体三钍簇合物[{Th(η⁵-C₅H₅)(μ-Cl)}₃{K(THF)₃}]中观察到了独特的钍-钍键，尽管钍键具有σ芳香性这一说法受到了质疑。在此，提出了一种新型的核壳同生键合模型来描述该三钍簇合物的稳定性。该模型涉及钍核中的一个3c-2e键和一个多中心的(ThCl)电荷转移键，有12个电子沿外壳散射。为了区分3c-2e键和电荷转移键的强度，采用属于从头算价键(VB)理论的块定域波函数(BLW)方法来构建钍核键的严格核/壳定域态及其贡献的共价共振结构。通过与σ芳香性的H₃⁺和非芳香性的Li₃⁺进行比较，计算得到的共振能和额外的环共振能证实了该钍核键确实是离域的且具有σ芳香性。
