2026-04-14T16:38:23Zhttps://uvadoc.uva.es/oai/request

oai:uvadoc.uva.es:10324/772952025-12-19T20:08:46Zcom_10324_1186com_10324_931com_10324_894col_10324_1404

Miranda, Matias O. Duarte, Darío Jorge Roberto Rayón Rico, Víctor Manuel 2025-08-29T09:31:12Z 2025-08-29T09:31:12Z 2025 Physical Chemistry Chemical Physics, 2025 vol. 27, n. 6, p. 3330-40 1463-9076 https://uvadoc.uva.es/handle/10324/77295 10.1039/D4CP03882G 3330 6 3340 Physical Chemistry Chemical Physics 27 1463-9084 Producción Científica This article reports a theoretical study on the halogen exchange reactions YX + CHO → Y + XCHO (with Y = F, Cl, Br; X = Cl, Br, I) carried out at a high level of accuracy using coupled-cluster based methodologies including CCSD(T)-F12, CCSD(T)/CBS and CCSDT(Q)Λ. Most of the reactions are exothermic at room temperature, with the exception of the reactions FI + CHO → F + ICHO and ClI + CHO → Cl + ICHO. Exothermicity follows two concurrent trends established by the strength of the bonds being cleaved and formed: Y = F < Cl < Br (X–Y bond strength) and X = Cl > Br > I (C–X bond strength). Regarding the topology of the potential energy surfaces, we find that at the CCSD level of theory only some processes present the expected reaction profile: a pre-reactive complex (preRC) followed by a transition state (TS) and a post-reactive complex (postRC). However, when triple excitations are taken into account, all reactions become barrierless with no preRC/TS along the reaction profile. We propose that halogen-mediated interactions through the σ-hole, which represent the driving force in the early stages of the title reactions, are responsible for the absence of a tight transition state. We suggest that the strength of these interactions formed during these processes triggers the onset of the halogen atom exchange, before the preRC is formed. Therefore, this study aims to show the relevant role of halogen-mediated interactions in the mechanism of reactions in which a halogen atom is abstracted by the formyl radical (CHO). Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) / Asociación Universitaria Iberoamericana de Postgrado (AUIP) Secretaría General de Ciencia y Tecnoclogía (SGCT) - UNNE: PI-22V002 Ministerio de Ciencia e Innovación (MCIN) / Agencia Estatal de Investigación (AEI): PID2020- 117742GB-I00 (MCIN/AEI/10.13039/501100011033) application/pdf eng Royal Society chemistry info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/3.0/ © the Owner Societies 2025 Attribution 3.0 Unported Química Física Halógenos Radicales formilo Química de radicales libres 2210 Química Física 2306 Química Orgánica The influence of halogen-mediated interactions on halogen abstraction reactions by formyl radicals info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion https://pubs.rsc.org/en/content/articlelanding/2025/cp/d4cp03882g SI