University of Illinois Urbana-Champaign

Internal Rotation Of The Acetyl Methyl Group In Methyl Alkyl Ketones: The Microwave Spectrum Of Octan-2-one

Kleiner, Isabelle

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5263.pdf
WH07_5263.pdf

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https://hdl.handle.net/2142/111111

Description

Title
Internal Rotation Of The Acetyl Methyl Group In Methyl Alkyl Ketones: The Microwave Spectrum Of Octan-2-one
Author(s)
Kleiner, Isabelle
Contributor(s)
  • Nguyen, Ha Vinh Lam
  • Stahl, Wolfgang
  • SCHWELL, Martin
  • Schoengen, Damian
  • Andresen, Maike
Issue Date
2021-06-23
Keyword(s)
Mini-symposium: Large Amplitude Motions
Date of Ingest
  • 2021-09-24T21:09:01Z
  • 2022-01-21T16:09:29Z
Abstract
Methyl \textit{n}-alkyl ketones form a class of molecules with interesting internal dynamics in the gas-phase. They contain two methyl groups undergoing internal rotations. To explore the link between structure and barrier heights in ketones, investigations on a series of saturated methyl \textit{n}-alkyl ketones were performed, i.e. pentan-2-one\footnote{M. Andresen, I. Kleiner, M. Schwell, W. Stahl, H. V. L. Nguyen, J. Phys. Chem. A 2018, 122, 7071-7078} hexan-2-one\footnote{M. Andresen, I. Kleiner, M. Schwell, W. Stahl, H. V. L. Nguyen, ChemPhysChem 2019, 20, 2063-2073}, heptan-2-one\footnote{M. Andresen, I. Kleiner, M. Schwell, W. Stahl, H. V. L. Nguyen, J. Phys. Chem. A 2020, 124, 1353-1361.} and octan-2-one\footnote{M. Andresen, D. Schöngen, I. Kleiner, M. Schwell, W. Stahl, H. V. L. Nguyen, ChemPhysChem 2020, 21, 2206-2216}. The molecular jet Fourier-transform microwave spectrum of octan-2-one was recorded between 2.0 and 40.0 GHz, revealing two conformers, one with C$_{1}$ and one with C$_{s}$ symmetry. The barriers to internal rotation of the acetyl methyl group were determined to be 233.340(28) cm$^{-1}$ and 185.3490(81) cm$^{-1}$, respectively, confirming the link between conformation and barrier height already established for other methyl alkyl ketones. The study combined high level \textit{ab initio} calculations with experimentally dervived rotational and torsional parameters using the XIAM\footnote{H. Hartwig, H. Dreizler, Z. Naturforsch. 1996, 51a, 923-932} and BELGI-C$_{1}$ (or BELGI-C$_{s}$)\footnote{I. Kleiner, J. T. Hougen, J. Chem. Phys. 2003, 119, 5505-5509.} codes. Results from the various fits will be presented. Finally comparisons to molecules in the literature and structural aspects of the conformers generally observed in methyl \textit{n}-alkyl ketones will be reviewed.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
Text
Genre of Resource
Conference Paper / Presentation
Language
eng
Permalink
http://hdl.handle.net/2142/111111
DOI
10.15278/isms.2021.WH07

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Abstracts & Presentations - 2021 International Symposium on Molecular Spectroscopy PRIMARY