title: Communication: Infrared spectroscopy of protonated allyl-trimethylsilane: Evidence for the β-silyl effect.
abstract: β-trimethylsilyl-2-propyl cation has been formed by the gas phase protonation of allyl-trimethylsilane and characterized by infrared multiple photon dissociation spectroscopy. The experimental Cβ-Cα (+) stretching feature at 1586 cm(-1), remarkably blue-shifted with respect to a C-C single bond stretching mode, is indicative of high double bond character, a signature of β-stabilizing effect due to hyperconjugation of the trimethylsilyl group in the β-position with respect to the positively charged carbon. Density functional theory calculations at the B3LYP∕6-311++G(2df,2p) level yield the optimized geometries and IR spectra for candidate isomeric cations and for neutral and charged reference species.
authors: Dipartimento di Chimica e Tecnologie del Farmaco, Università di Roma La Sapienza, P. le A. Moro 5, I-00185 Roma, Italy. barbara.chiavarino@uniroma1.it
authors: Barbara
authors: B
authors: Chiavarino
authors: Maria Elisa
authors: ME
authors: Crestoni
authors: Joel
authors: J
authors: Lemaire
authors: Philippe
authors: P
authors: Maitre
authors: Simonetta
authors: S
authors: Fornarini