Isolation and Versatile Derivatization of an Unsaturated Anionic Silicon Cluster (Siliconoid)

Abstract

The characteristic features of bulk silicon surfaces are echoed in the related partially substituted—and thus unsaturated—neutral silicon clusters (siliconoids). The incorporation of siliconoids into more‐extended frameworks is promising owing to their unique electronic features, but further developments in this regard are limited by the notable absence of functionalized siliconoid derivatives until now. Herein we report the isolation and full characterization of the lithium salt of an anionic R5Si6‐siliconoid, thus providing the missing link between silicon‐based Zintl anions and siliconoid clusters. Proof‐of‐principle for the high potential of this species for the efficient transfer of the intact unsaturated R5Si6 moiety is demonstrated by clean reactions with representative electrophiles of Groups 13, 14, and 15.

Atomically Precise Expansion of Unsaturated Silicon Clusters

“…[21] Applying the OLYP functional, the calculated 29 Si chemical shifts of the B3LYPoptimized model Tip 5 Si 7 (Li)thf 3 (14 Tip ·Li + (thf) 3 )nicely reproduce the experimental data of 14·Li + (thf) 3 (Table 1). As imilar relative deshielding had been observed between the neutral Si 6 siliconoid 4 and the corresponding lithiated species 12.…”

Cooperative Noncovalent Interactions Induce Ion Pair Separation in Diphenylsilanides

“…We report the structural characterization of silyl anions (silanides) separated from a potassium countercation by unexpected noncovalent interactions. Silanides, like carbanions, are versatile reagents in organic and inorganic synthesis and these materials represent an intriguing set of hard/soft congeners . Controlling ion pair separation in solution is a challenge with profound consequences for reactivity and selectivity: strong Coulombic attraction between oppositely charged species ties the nucleophilic anion to its countercation, inhibiting reaction with a desired electrophile .…”

Erweiterung ungesättigter Siliciumcluster mit atomarer Genauigkeit

“…Basierend auf unseren Arbeiten über das erste anionische Silicoid mit teilweiser Substitution Si 6 R 5 (12,R= Tip = 2,4,6-Tr iisopropylphenyl) [21] haben wir Versuche unternommen, eine Methode zur atomar präzisen Clustererweiterung zu entwickeln. Da die Abgangsgruppeneigenschaften des Pentamethylcyclopentadienylliganden (Cp*) in der Hauptgruppenchemie gut etabliert sind, [22] spekulierten wir, dass Jutzis Decamethylsilicocen (SiCp* 2 ) [23] (trotz des zehnfach-koordinierten Siliciumatoms) mit 12 als elektrophile Quelle für genau ein Siliciumatom reagieren kçnnte.B isher wurde als Elektrophil nur das entsprechende Kation Cp*Si + BAr 4 À (Ar = Pentafluorphenyl) [24] eingesetzt.…”