2-Benzylindane radical cations in the gas phase (Part I): Substituent effects on a stereoselective McLafferty reaction and related hydrogen transfer processes
| Autor: | Hans-Friedrich Grützmacher, Dietmar Kuck |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2017 |
| Předmět: |
ipso-Protonation
Substituent McLafferty reaction Proton affinity 010402 general chemistry Photochemistry 01 natural sciences Ion chemistry.chemical_compound Fragmentation (mass spectrometry) Computational chemistry Substituent effects Moiety Physical and Theoretical Chemistry Instrumentation Spectroscopy Chemistry 010401 analytical chemistry Condensed Matter Physics 0104 chemical sciences Distonic ions Arenium ion Mass spectrum Distonic ion transfer Hydrogen |
| Popis: | In the present and the accompanying article, the unimolecular fragmentation of the radical cations of 2-benzylindane and eleven derivatives bearing meta- or para-substituents at the benzylic moiety has been studied with a special focus on the hydrogen exchange that precedes the McLafferty reaction. Standard EI mass spectra, low-energy (11 eV) mass spectra and mass-analyzed ion kinetic energy (MIKE) spectra were recorded to probe the excitation-energy and ion-lifetime dependence of the fragmentation and the hydrogen exchange. Density-functional theory calculations were used to rationalize the substituent effects on the competition between the benzylic cleavage and the McLafferty reaction and to clarify the role of the distonic arenium ion-type intermediate formed by the gamma-hydrogen-transfer step of the McLafferty reaction. The ipso-protonolysis of the benzyl residue giving rise to the loss of substituted benzenes specifically from most of the para-isomers was also found to reflect the hydrogen exchange. (C) 2016 Elsevier B.V. All rights reserved. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|