The influence of ring strain on the formation of Si–H–Si stabilised oligosilanylsilyl cations

Abstract

Hydride transfer between Si(SiMe₂H)₄ (2) and [Ph₃C][B(C₆F₅)₄] in 3-fluorotoluene yields the intermolecularly silane-stabilised silylium ion [((HMe₂Si)₃SiSiMe₂)₂H]⁺ ([5]⁺), independently of the amount of [Ph₃C][B(C₆F₅)₄] (0.5, 1.0 or 2.0 equiv.) used. The cyclic silane-stabilised silylium ion [4]⁺ is not detected by NMR spectroscopy. This result demonstrates the influence of ring strain effects on the formation of intra- ([4]⁺) or intermolecularly ([5]⁺) Si–H–Si bridged silyl cations.