Dramatic Conformer-Dependent Reactivity of the Acetaldehyde Oxide Criegee Intermediate with Dimethylamine Via a 1,2-Insertion Mechanism

Michael F Vansco; Meijun Zou; Ivan O Antonov; Krupa Ramasesha; Brandon Rotavera; David L Osborn; Yuri Georgievskii; Carl J Percival; Stephen J Klippenstein; Craig A Taatjes; Marsha I Lester; Rebecca L Caravan

doi:10.1021/acs.jpca.1c08941

Dramatic Conformer-Dependent Reactivity of the Acetaldehyde Oxide Criegee Intermediate with Dimethylamine Via a 1,2-Insertion Mechanism

J Phys Chem A. 2022 Feb 10;126(5):710-719. doi: 10.1021/acs.jpca.1c08941. Epub 2021 Dec 23.

Authors

Michael F Vansco¹, Meijun Zou², Ivan O Antonov^{3

4}, Krupa Ramasesha⁴, Brandon Rotavera^{4

5

6}, David L Osborn^{4

7}, Yuri Georgievskii¹, Carl J Percival⁸, Stephen J Klippenstein¹, Craig A Taatjes⁴, Marsha I Lester², Rebecca L Caravan^{1

4}

Affiliations

¹ Chemical Sciences and Engineering Division, Argonne National Laboratory, Lemont, Illinois 60439, United States.
² Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States.
³ Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208-3112, United States.
⁴ Combustion Research Facility, Mailstop 9055, Sandia National Laboratories, Livermore, California 94551, United States.
⁵ School of Environmental, Civil, Agricultural, and Mechanical Engineering, University of Georgia, Athens, Georgia 30602, United States.
⁶ Department of Chemistry, University of Georgia, Athens, Georgia 30602, United States.
⁷ Department of Chemical Engineering, University of California, Davis, California 95616, United States.
⁸ NASA Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, California 91109, United States.

PMID: 34939803
DOI: 10.1021/acs.jpca.1c08941

Abstract

The reactivity of carbonyl oxides has previously been shown to exhibit strong conformer and substituent dependencies. Through a combination of synchrotron-multiplexed photoionization mass spectrometry experiments (298 K and 4 Torr) and high-level theory [CCSD(T)-F12/cc-pVTZ-F12//B2PLYP-D3/cc-pVTZ with an added CCSDT(Q) correction], we explore the conformer dependence of the reaction of acetaldehyde oxide (CH₃CHOO) with dimethylamine (DMA). The experimental data support the theoretically predicted 1,2-insertion mechanism and the formation of an amine-functionalized hydroperoxide reaction product. Tunable-vacuum ultraviolet photoionization probing of anti- or anti- + syn-CH₃CHOO reveals a strong conformer dependence of the title reaction. The rate coefficient of DMA with anti-CH₃CHOO is predicted to exceed that for the reaction with syn-CH₃CHOO by a factor of ∼34,000, which is attributed to submerged barrier (syn) versus barrierless (anti) mechanisms for energetically downhill reactions.