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CO2_SO2_v2.pdf (1.72 MB)
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CO2 or SO2: Should It Stay or Should It Go?

preprint
revised on 21.02.2019 and posted on 21.02.2019 by Gabriel dos Passos Gomes, Alexander Wimmer, Joel Smith, Burkhard König, Igor Alabugin

A broad computational analysis of carbon-centered radical formation via the loss of either CO2 or SO2 from the respective RXO2 radical precursors (X = C or S) reveals dramatic differences between these two types of dissociative processes. Whereas the C-C scission with the loss of CO2 is usually exothermic, the C-S scission with the loss of SO2 is generally endothermic. However, two factors can make the C-S scissions thermodynamically favorable: increased entropy, characteristic for the dissociative processes, and stereoelectronic influences of substituents. The threshold between endergonic and exergonic C-S fragmentations depends on subtle structural effects. In particular, the degree of fluorination in a radical precursor has a notable impact on the reaction outcome. This study aims to demystify the intricacies in reactivity regarding the generation of radicals from sulfinates and carboxylates, as related to their role in radical cross-coupling.

Funding

National Science Foundation (Grant CHE-1800329)

NSF XSEDE (TG-CHE160006)

German Science foundation (GRK 1626; Koselleck)

History

Email Address of Submitting Author

gabriel.gomes@utoronto.ca

Institution

Florida State University

Country

USA

ORCID For Submitting Author

0000-0002-8235-5969

Declaration of Conflict of Interest

We declare no conflict of interests.

Version Notes

Version 2 with updated plots and new MP2 data.

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