The Criegee intermediates are carbonyl oxides that play critical roles in ozonolysis of alkenes in the atmosphere. So far, the mid-infrared spectrum of only the simplest Criegee intermediate CH2OO has been reported. Methyl substitution of CH2OO produces two conformers of CH3CHOO and consequently complicates the infrared spectrum. Here we report the transient infrared spectrum of syn- and anti-CH3CHOO, produced from CH3CHI + O2 in a flow reactor, using a step-scan Fourier-transform spectrometer. Guided and supported by high-level full-dimensional quantum calculations, rotational contours of the four observed bands are simulated successfully and provide definitive identification of both conformers. Furthermore, anti-CH3CHOO shows a reactivity greater than syn-CH3CHOO towards NO/NO2; at the later period of reaction, the spectrum can be simulated with only syn-CH3CHOO. Without NO/NO2, anti-CH3CHOO also decays much faster than syn-CH3CHOO. The direct infrared detection of syn- and anti-CH3CHOO should prove useful for field measurements and laboratory investigations of the Criegee mechanism.
Lin, Hui-Yu, et al. "Infrared identification of the Criegee intermediates <em>syn</em>- and <em>anti</em>-CH<sub>3</sub>CHOO, and their distinct conformation-dependent reactivity." Nature Communications, vol. 6, no. 1, May. 2015. https://doi.org/10.1038/ncomms8012
Lin, Hui-Yu, Huang, Yu-Hsuan, Wang, Xiaohong, Bowman, Joel M., Nishimura, Yoshifumi, Witek, Henryk A., & Lee, Yuan-Pern (2015). Infrared identification of the Criegee intermediates <em>syn</em>- and <em>anti</em>-CH<sub>3</sub>CHOO, and their distinct conformation-dependent reactivity. Nature Communications, 6(1). https://doi.org/10.1038/ncomms8012
Lin, Hui-Yu, Huang, Yu-Hsuan, Wang, Xiaohong, et al., "Infrared identification of the Criegee intermediates <em>syn</em>- and <em>anti</em>-CH<sub>3</sub>CHOO, and their distinct conformation-dependent reactivity," Nature Communications 6, no. 1 (2015), https://doi.org/10.1038/ncomms8012
@article{osti_1623972,
author = {Lin, Hui-Yu and Huang, Yu-Hsuan and Wang, Xiaohong and Bowman, Joel M. and Nishimura, Yoshifumi and Witek, Henryk A. and Lee, Yuan-Pern},
title = {Infrared identification of the Criegee intermediates <em>syn</em>- and <em>anti</em>-CH<sub>3</sub>CHOO, and their distinct conformation-dependent reactivity},
annote = {The Criegee intermediates are carbonyl oxides that play critical roles in ozonolysis of alkenes in the atmosphere. So far, the mid-infrared spectrum of only the simplest Criegee intermediate CH2OO has been reported. Methyl substitution of CH2OO produces two conformers of CH3CHOO and consequently complicates the infrared spectrum. Here we report the transient infrared spectrum of syn- and anti-CH3CHOO, produced from CH3CHI + O2 in a flow reactor, using a step-scan Fourier-transform spectrometer. Guided and supported by high-level full-dimensional quantum calculations, rotational contours of the four observed bands are simulated successfully and provide definitive identification of both conformers. Furthermore, anti-CH3CHOO shows a reactivity greater than syn-CH3CHOO towards NO/NO2; at the later period of reaction, the spectrum can be simulated with only syn-CH3CHOO. Without NO/NO2, anti-CH3CHOO also decays much faster than syn-CH3CHOO. The direct infrared detection of syn- and anti-CH3CHOO should prove useful for field measurements and laboratory investigations of the Criegee mechanism.},
doi = {10.1038/ncomms8012},
url = {https://www.osti.gov/biblio/1623972},
journal = {Nature Communications},
issn = {ISSN 2041-1723},
number = {1},
volume = {6},
place = {United States},
publisher = {Nature Publishing Group},
year = {2015},
month = {05}}
USDOE Office of Science (SC); Taiwan Ministry of Science and Technology (MOST); Ministry of Education; National Aeronautics and Space Administration (NASA)