The Microwave Spectrum of Methyl Chlorodifluoroacetate: Methyl Internal Rotation and Chlorine Nuclear Electric Quadrupole Coupling

Author

B. E. Long
Robert A. Powoski
Garry S. Grubbs, Missouri University of Science and TechnologyFollow
William C. Bailey
Stephen A. Cooke

Abstract

A chirped pulse microwave spectrometer has been used to record microwave spectra of the ³⁵Cl and ³⁷Cl isotopologues of methyl chlorodifluoroacetate, CClF₂C(O)OCH₃, between 8 GHz and 16 GHz. the target compound was spectroscopically examined as it participated in a supersonic expansion of argon. Only one conformer was observed. the rotational spectra were recorded with sufficient resolution to observe (i) splittings due to the internal rotation of the methyl group, and (ii) splittings from the coupling of the chlorine quadrupolar nucleus. a total of 785 transitions have had quantum numbers assigned. Analysis of the spectra observed has produced an experimental barrier to the methyl group internal rotation, V₃, of 370(2) cm^-1. It is noted that this barrier is a little lower than that determined for methyl acetate [V₃ = 425 cm^-1, J. Sheridan, W. Bossert and A. Bauder, J. Mol. Spectrosc., 80 (1980) 1-11], and this is rationalized through a comparison of molecular structures. Lastly, all components of both the ³⁵Cl and ³⁷Cl chlorine nuclear electric quadrupolar coupling tensor have been determined.

Recommended Citation

B. E. Long et al., "The Microwave Spectrum of Methyl Chlorodifluoroacetate: Methyl Internal Rotation and Chlorine Nuclear Electric Quadrupole Coupling," Journal of Molecular Spectroscopy, vol. 266, no. 1, pp. 21 - 26, Elsevier, Jan 2011.

The definitive version is available at https://doi.org/10.1016/j.jms.2011.01.001

Department(s)

Chemistry

International Standard Serial Number (ISSN)

0022-2852

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2011 Elsevier, All rights reserved.

Publication Date

01 Jan 2011