Six-fold-symmetry internal rotation in toluenes: the low barrier challenge of 2,6- and 3,5-difluorotoluene

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

Authors

  • K. P. Rajappan Nair
  • Michaela K. Jahn
  • Alberto Lesarri
  • Vadim V. Ilyushin
  • Jens Uwe Grabow

Research Organisations

External Research Organisations

  • Universidad de Valladolid
  • Institute of Radio Astronomy National Academy of Sciences of Ukraine
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Details

Original languageEnglish
Pages (from-to)26463-26470
Number of pages8
JournalPhysical Chemistry Chemical Physics
Volume17
Issue number39
Publication statusPublished - 8 Sept 2015

Abstract

Pure six-fold symmetry (V6) internal rotation poses significant challenges to experimental and theoretical determination, as the very low torsional barriers result in huge tunneling splittings difficult to identify and to model. Here we resolved the methyl group internal rotation dynamics of 2,6- and 3,5-difluorotoluene using a newly developed computer code especially adapted to V6 problems. The jet-cooled rotational spectra of the title molecules in the 5-25 GHz region revealed internal rotation tunneling doublings of up to 3.6 GHz, which translated in methyl group potential barriers of V6 = 0.14872(24) and 0.0856(10) kJ mol-1, respectively, in the vibrational ground-state. Additional information on Stark effects and carbon isotopic species in natural abundance provided structural data and the electric dipole moments for both molecules. Ab initio calculations at the MP2 level do not reproduce the tiny torsional barriers, calling for experiments on other systems and additional theoretical models.

ASJC Scopus subject areas

Cite this

Six-fold-symmetry internal rotation in toluenes: the low barrier challenge of 2,6- and 3,5-difluorotoluene. / Rajappan Nair, K. P.; Jahn, Michaela K.; Lesarri, Alberto et al.
In: Physical Chemistry Chemical Physics, Vol. 17, No. 39, 08.09.2015, p. 26463-26470.

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

Rajappan Nair KP, Jahn MK, Lesarri A, Ilyushin VV, Grabow JU. Six-fold-symmetry internal rotation in toluenes: the low barrier challenge of 2,6- and 3,5-difluorotoluene. Physical Chemistry Chemical Physics. 2015 Sept 8;17(39):26463-26470. doi: 10.1039/c5cp03751d
Rajappan Nair, K. P. ; Jahn, Michaela K. ; Lesarri, Alberto et al. / Six-fold-symmetry internal rotation in toluenes : the low barrier challenge of 2,6- and 3,5-difluorotoluene. In: Physical Chemistry Chemical Physics. 2015 ; Vol. 17, No. 39. pp. 26463-26470.
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T2 - the low barrier challenge of 2,6- and 3,5-difluorotoluene

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AU - Jahn, Michaela K.

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AU - Ilyushin, Vadim V.

AU - Grabow, Jens Uwe

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