Dynamics of Si#H#Si bridges in agostically stabilized silylium ions

Samat Tussupbayev, Georgii I. Nikonov, Sergei F. Vyboishchikov

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

The silylium ion [C6(SiMe2)(SiHMe2) 5]+ offers an amazing example of multiple Si ···H interactions. It exhibits a symmetric Si α - H - Siα motif supported by two additional Siβ - H···Siα agostic interactions. This cation is highly fluctional in NMR spectra at room temperature due to shift of the hydride bridge. The DFT calculations show that the hydride shift is related to internal rotation of silyl groups. We performed NMR, static DFT, and dynamics studies of this process and found two possible mechanisms, associated with internal rotation of either β-or γ-silyls. The energy barrier is largely caused by the silyl internal rotation, whereas the hydride transfer itself is intrinsically quite easy. The γ-silyl rotation is somewhat more favorable than the β-silyl rotation. Vibrational dynamics of the cation is also discussed.

Original languageEnglish (US)
Pages (from-to)1199-1209
Number of pages11
JournalJournal of Physical Chemistry A
Volume113
Issue number7
DOIs
StatePublished - Feb 19 2009
Externally publishedYes

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