The 1-phenyl-1-(trimethylsilyl)ethyl cation: An NMR spectroscopic and computational study of the α-silyl effect in benzyl cations

Arseni Kostenko; Bernhard Müller; Frank Peter Kaufmann; Yitzhak Apeloig; Hans Ullrich Siehl

doi:10.1002/ejoc.201101741

The 1-phenyl-1-(trimethylsilyl)ethyl cation: An NMR spectroscopic and computational study of the α-silyl effect in benzyl cations

Arseni Kostenko, Bernhard Müller, Frank Peter Kaufmann, Yitzhak Apeloig, Hans Ullrich Siehl

Technion - Israel Institute of Technology

Research output: Contribution to journal › Article › peer-review

Abstract

The 1-phenyl-1-(trimethylsilyl)ethyl cation is generated as a persistent species in solution and characterized experimentally by ¹H, ¹³C, and ²⁹Si NMR spectroscopy. The α-silyl effect is elucidated by comparison with other benzyl cations, such as cumyl and 1-phenylethyl cations. Concomitant quantum chemical calculations of structures, relative thermodynamic stabilities, chemical shifts, and the harmonic oscillator model of aromaticity (HOMA) indices are congruent with the analysis of the experimental NMR spectroscopy results; therefore, we conclude that, in benzyl cations, the α-silyl substituent is stabilizing with respect to H, but destabilizing relative to a methyl group.

Original language	English
Pages (from-to)	1730-1736
Number of pages	7
Journal	European Journal of Organic Chemistry
Issue number	9
DOIs	https://doi.org/10.1002/ejoc.201101741
State	Published - Mar 2012

Keywords

Ab initio calculations
Aromaticity
Carbocations
Density functional calculations
NMR spectroscopy
Silicon
Substituent effects

All Science Journal Classification (ASJC) codes

Physical and Theoretical Chemistry
Organic Chemistry

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10.1002/ejoc.201101741

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title = "The 1-phenyl-1-(trimethylsilyl)ethyl cation: An NMR spectroscopic and computational study of the α-silyl effect in benzyl cations",

abstract = "The 1-phenyl-1-(trimethylsilyl)ethyl cation is generated as a persistent species in solution and characterized experimentally by 1H, 13C, and 29Si NMR spectroscopy. The α-silyl effect is elucidated by comparison with other benzyl cations, such as cumyl and 1-phenylethyl cations. Concomitant quantum chemical calculations of structures, relative thermodynamic stabilities, chemical shifts, and the harmonic oscillator model of aromaticity (HOMA) indices are congruent with the analysis of the experimental NMR spectroscopy results; therefore, we conclude that, in benzyl cations, the α-silyl substituent is stabilizing with respect to H, but destabilizing relative to a methyl group.",

keywords = "Ab initio calculations, Aromaticity, Carbocations, Density functional calculations, NMR spectroscopy, Silicon, Substituent effects",

author = "Arseni Kostenko and Bernhard M{\"u}ller and Kaufmann, {Frank Peter} and Yitzhak Apeloig and Siehl, {Hans Ullrich}",

year = "2012",

month = mar,

doi = "10.1002/ejoc.201101741",

language = "الإنجليزيّة",

pages = "1730--1736",

journal = "European Journal of Organic Chemistry",

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T1 - The 1-phenyl-1-(trimethylsilyl)ethyl cation

T2 - An NMR spectroscopic and computational study of the α-silyl effect in benzyl cations

AU - Kostenko, Arseni

AU - Müller, Bernhard

AU - Kaufmann, Frank Peter

AU - Apeloig, Yitzhak

AU - Siehl, Hans Ullrich

PY - 2012/3

Y1 - 2012/3

N2 - The 1-phenyl-1-(trimethylsilyl)ethyl cation is generated as a persistent species in solution and characterized experimentally by 1H, 13C, and 29Si NMR spectroscopy. The α-silyl effect is elucidated by comparison with other benzyl cations, such as cumyl and 1-phenylethyl cations. Concomitant quantum chemical calculations of structures, relative thermodynamic stabilities, chemical shifts, and the harmonic oscillator model of aromaticity (HOMA) indices are congruent with the analysis of the experimental NMR spectroscopy results; therefore, we conclude that, in benzyl cations, the α-silyl substituent is stabilizing with respect to H, but destabilizing relative to a methyl group.

AB - The 1-phenyl-1-(trimethylsilyl)ethyl cation is generated as a persistent species in solution and characterized experimentally by 1H, 13C, and 29Si NMR spectroscopy. The α-silyl effect is elucidated by comparison with other benzyl cations, such as cumyl and 1-phenylethyl cations. Concomitant quantum chemical calculations of structures, relative thermodynamic stabilities, chemical shifts, and the harmonic oscillator model of aromaticity (HOMA) indices are congruent with the analysis of the experimental NMR spectroscopy results; therefore, we conclude that, in benzyl cations, the α-silyl substituent is stabilizing with respect to H, but destabilizing relative to a methyl group.

KW - Ab initio calculations

KW - Aromaticity

KW - Carbocations

KW - Density functional calculations

KW - NMR spectroscopy

KW - Silicon

KW - Substituent effects

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U2 - 10.1002/ejoc.201101741

DO - 10.1002/ejoc.201101741

M3 - مقالة

SN - 1434-193X

SP - 1730

EP - 1736

JO - European Journal of Organic Chemistry

JF - European Journal of Organic Chemistry

IS - 9

ER -

The 1-phenyl-1-(trimethylsilyl)ethyl cation: An NMR spectroscopic and computational study of the α-silyl effect in benzyl cations

Abstract

Keywords

All Science Journal Classification (ASJC) codes

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