EXPERIMENTAL AND THEORETICAL STUDIES OF SILACYCLOHEPTATRIENYL CATION FORMATION FROM PHENYLSILANE
SCIE
SCOPUS
- Title
- EXPERIMENTAL AND THEORETICAL STUDIES OF SILACYCLOHEPTATRIENYL CATION FORMATION FROM PHENYLSILANE
- Authors
- Jarek, RL; Shin, SK
- Date Issued
- 1997-07-09
- Publisher
- AMER CHEMICAL SOC
- Abstract
- The formation of C6SiH7+ from phenylsilane was studied using Fourier transform ion cyclotron resonance spectrometry and by ab initio calculations. The (parent - H or D)(+) ions were produced by electron impact (EI) dissociation of C6H5SiH3 and C6H5SiD3, and their bimolecular reactivities toward phenylsilane, cycloheptatriene, benzyl chloride, benzene-d(6), and toluene-d(8) were examined. The reactive component that abstracts hydride from phenylsilane and cycloheptatriene or chloride from benzyl chloride is mostly the phenylsilyl cation C6H5SiH2+. The identity of the unreactive component was characterized by collision-induced dissociation and bimolecular chemical reactivity. The low-energy collision-induced dissociation of the unreactive C6SiH7+ ion with argon yielded SiH+ with a loss of C6H6 and C6SiH5+ with a loss of H-2 as the primary fragments. Vibrationally hot C6SiH7+ ions from EI of C6H5SiH3 reacted with benzene-d(6) to form C6D6 . SiH+ adducts, which after few seconds of cooling delay remained unreactive toward cycloheptatriene. Ab initio calculations predict the hydride affinity of C6H6 . SiH+ that forms C6H6 + SiH2 to be comparable to or lower than that of tropylium ion. The chloride affinity of C6H6 . SiH+ that forms C6H6 + SiHCl is estimated to be similar to 4 kcal mol(-1) lower than that of the benzyl cation. Both experiment and theory suggest the C6H6 . SiH+ adduct as the unreactive C6SiH7+ component and not the silacycloheptatrienyl cation. The mechanism of the formation of C6H6 . SiH+ is presented based on the theoretical energetics of radical cations and the transition state for the [1,2] sigmatropic migration of an alpha-H.
- Keywords
- COLLISION-INDUCED DISSOCIATION; TRANSFORM MASS-SPECTROMETRY; GAS-PHASE; ION; TROPYLIUM; TOLUENE; HEATS; STABILITIES; ROTATION; ISOMERS
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/29063
- DOI
- 10.1021/ja9630295
- ISSN
- 0002-7863
- Article Type
- Article
- Citation
- JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, vol. 119, no. 27, page. 6376 - 6383, 1997-07-09
- Files in This Item:
- There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.