The Formal Combination of Three Singlet Biradicaloid Entities to a Singlet Hexaradicaloid Metalloid Ge₁₄[Si(SiMe₃)₃]₅[Li(THF)₂]₃ Cluster

The reaction of GeBr with LiSi(SiMe3)3 leads to the metalloid cluster compound [(THF)2Li]3Ge14[Si(SiMe3)3]5 (1). After the introduction of a first cluster of this type, in which 14 germanium atoms form an empty polyhedron, [(THF)2Li]3Ge14[Ge(SiMe3)3]5 (2), we present here further investigations on 1 to obtain preliminary insight into its chemical and bonding properties. The molecular structure of 1 is determined via X-ray crystal structure solution using synchrotron radiation. The electronic structure of the Ge14 polyhedron is further examined by quantum chemical calculations, which indicate that three singlet biradicaloid entities formally combine to yield the singlet hexaradicaloid character of 1. Moreover, the initial reactions of 1 after elimination of the [Li(THF)2]+ groups by chelating ligands (e.g., TMEDA or 12-crown-4) are presented. Collision induced dissociation experiments in the gas phase, employing FT-ICR mass spectrometry, lead to the elimination of the singlet biradicaloid Ge5H2[Si(SiMe3)3]2 cluster. The unique multiradicaloid bonding character of the metalloid cluster 1 might be used as a model for reactions and properties in the field of surface science and nanotechnology.溴化锗(I)（GeBr）与三(三甲基硅基)硅基锂（LiSi(SiMe₃)₃）发生反应，得到类金属簇合物[(四氢呋喃(THF))₂Li]₃Ge₁₄[Si(SiMe₃)₃]₅（化合物1）。在本课题组首次报道此类由14个锗原子构成空多面体的簇合物——[(四氢呋喃(THF))₂Li]₃Ge₁₄[Ge(SiMe₃)₃]₅（化合物2）——后，本文针对化合物1展开进一步研究，以初步探明其化学性质与成键特性。通过同步辐射（synchrotron radiation）X射线晶体结构解析，确定了化合物1的分子结构。针对Ge₁₄多面体的电子结构，本文通过量子化学计算开展了深入分析，结果表明三个单线态类双自由基实体经形式上的结合，使化合物1呈现出单线态六自由基体的特征。此外，本文还报道了化合物1经螯合配体（如四甲基乙二胺(TMEDA)或12-冠-4(12-crown-4)）脱去[Li(THF)₂]⁺基团后的初始反应。采用傅里叶变换离子回旋共振质谱(FT-ICR质谱)开展气相碰撞诱导解离实验，结果得到脱除单线态类双自由基簇合物Ge₅H₂[Si(SiMe₃)₃]₂的产物。该类金属簇合物1独特的多自由基成键特性，可作为表面科学与纳米技术领域内相关反应与性质研究的模型体系。