A new strategy for the highly selective synthesis of tricyclo[2,2,0,02,5]hexasilanes R6Si6X2 (R = 2,4,6-Me3C6H2; X = H, Cl) and a bridged tricyclic R6Si6 dianion starting from the tetrachlorotrisilane RCl2SiSi(H)RSiCl2R (1) was described. Reduction of 1 with lithium naphthalene afforded tricyclohexasilane R6Si6H2 (2), which was halogenated to give the dichloride R6Si6Cl2 (3). Reduction of 3 with four equivalents of potassium graphite in the presence of 18-crown-6 afforded the first R6Si6 dianion (5) paired with [K(18-crown-6)]+2 counterions. The dianion 5 could act as a two-electron reductant toward transition metal halides and a nucleophile toward chlorosilanes. These reactions allowed the efficient and selective access to three types of silicon cages. The structures of the representative cages were confirmed by X-ray diffraction studies. Density functional theory calculations on 5 indicate that the negative charges are localized mainly on the anionic silicon atoms.

中文翻译：

---

R6Si6 Dianion 的分离，一种双阴离子六硅杂苯的桥连三环异构体

从四氯三硅烷开始高选择性合成三环 [2,2,0,02,5] 己硅烷 R6Si6X2（R = 2,4,6-Me3C6H2；X = H, Cl）和桥连三环 R6Si6 双阴离子的新策略描述了 RCl2SiSi(H)RSiCl2R (1)。用萘锂还原 1 得到三环己硅烷 R6Si6H2 (2)，将其卤化得到二氯化物 R6Si6Cl2 (3)。在 18-crown-6 存在下用四当量的钾石墨还原 3 得到第一个 R6Si6 二价阴离子 (5) 与 [K(18-crown-6)]+2 反离子配对。二价阴离子 5 可以作为过渡金属卤化物的双电子还原剂和氯硅烷的亲核试剂。这些反应允许有效和选择性地访问三种类型的硅笼。通过 X 射线衍射研究证实了代表性笼的结构。