Molecular species containing multiple bonds to aluminium have long been challenging synthetic targets. Despite recent landmark discoveries in this area, heterodinuclear Al–E multiple bonds (where E is a group-14 element) have remained rare and limited to highly polarized π-interactions (Al=E ↔ ⁺Al–E^–). Here we report the isolation of three alumanyl silanide anions that feature an Al–Si core stabilized by bulky substituents and a Si–Na interaction. Single-crystal X-ray diffraction studies, spectroscopic analysis and density functional theory calculations show that the Al–Si interaction possesses partial double bond character. Preliminary reactivity studies support this description of the compounds through two resonance structures: one that displays a predominant nucleophilic character of the sodium-coordinated silicon centre in the Al–Si core, as shown by silanide-like reactivity towards halosilane electrophiles and the CH-insertion of phenylacetylene. Moreover, we report an alumanyl silanide with a sequestered sodium cation. Cleavage of the Si–Na bond by [2.2.2]cryptand increases the double bond character of the Al–Si core to produce an anion with high aluminata-silene (^–Al=Si) character.

含有多个铝键的分子种类长期以来一直是合成目标的挑战。尽管最近在该领域取得了里程碑式的发现，但异双核 Al-E 多重键（其中 E 是第 14 族元素）仍然很少见，并且仅限于高度极化的 π 相互作用 ( Al =E ↔  ⁺ Al–E ^– )。在这里，我们报告了三种铝基硅烷阴离子的分离，其特征是通过大取代基和 Si-Na 相互作用稳定的 Al-Si 核。单晶X射线衍射研究、光谱分析和密度泛函理论计算表明Al-Si相互作用具有部分双键特征。初步反应性研究通过两种共振结构支持了对化合物的这种描述：一种共振结构显示出 Al-Si 核中钠配位硅中心的主要亲核特征，如对卤代硅烷亲电子试剂和 CH 插入的类似硅烷化物的反应性所示苯乙炔。此外，我们报告了一种具有螯合钠阳离子的铝基硅烷化物。[2.2.2]穴状配体对 Si-Na 键的裂解增加了 Al-Si 核的双键特性，产生具有高铝硅 (-Al ⁼ Si) 特性的阴离子。