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DOE OSTI · 1865338

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

Vansco, Michael F.·Zou, Meijun·Antonov, Ivan O.·Ramasesha, Krupa·Rotavera, Brandon·Osborn, David L.·Georgievskii, Yuri·Percival, Carl J.·Klippenstein, Stephen J.·Taatjes, Craig A.·Lester, Marsha I.·Caravan, Rebecca L.
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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, 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 (CH 3 CHOO) with dimethyl amine (DMA). The experimental data supports the theoretically predicted 1,2-insertion mechanism and the formation of an amine-functionalized hydroperoxide reaction product. Tunable-VUV photoionization probing of anti- or anti- + syn-CH 3 CHOO reveals a strong conformer dependence of the title reaction. Here, the rate coefficient of DMA with anti-CH 3 CHOO is predicted to exceed that for the reaction with syn-CH 3 CHOO by a factor of ~34,000, which is attributed to submerged barrier (syn) vs. barrierless (anti) mechanisms for energetically downhill reactions.

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73 NUCLEAR PHYSICS AND RADIATION PHYSICSchemical reactionsenergyionsmolecular structurephotoionization

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Vansco, Michael F., Zou, Meijun, Antonov, Ivan O., Ramasesha, Krupa, Rotavera, Brandon, Osborn, David L., Georgievskii, Yuri, Percival, Carl J., Klippenstein, Stephen J., Taatjes, Craig A., Lester, Marsha I., Caravan, Rebecca L.. 2021-12-23. Dramatic Conformer-Dependent Reactivity of the Acetaldehyde Oxide Criegee Intermediate with Dimethylamine Via a 1,2-Insertion Mechanism. https://doi.org/10.1021/acs.jpca.1c08941

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