DiLabio, Gino A. Franchi, Paola Lanzalunga, Osvaldo Lapi, Andrea Lucarini, Fiorella Lucarini, Marco Mazzonna, Marco Prasad, Viki Kumar Ticconi, Barbara 2017-06-16 A kinetic study of the hydrogen atom transfer (HAT) reactions from a series of organic compounds to the quinolinimide-N-oxyl radical (QINO) was performed in CH3CN. The HAT rate constants are significantly higher than those observed with the phthalimide- N-oxyl radical (PINO) as a result of enthalpic and polar effects due to the presence of the N-heteroaromatic ring in QINO. The relevance of polar effects is supported by theoretical calculations conducted for the reactions of the two N-oxyl radicals with toluene, which indicate that the HAT process is characterized by a significant degree of charge transfer permitted by the π-stacking that occurs between the toluene and the N-oxyl aromatic rings in the transition state structures. An increase in the HAT reactivity of QINO was observed in the presence of 0.15 M HClO4 and 0.15 M Mg(ClO4)2 due to the protonation or complexation with the Lewis acid of the pyridine nitrogen that leads to a further decrease in the electron density in the N-oxyl radical. These results fully support the use of N-hydroxyquinolinimide as a convenient substitute for N-hydroxyphthalimide in the catalytic aerobic oxidations of aliphatic hydrocarbons characterized by relatively high C–H bond dissociation energies. application/pdf https://folia.unifr.ch/global/documents/306103 https://folia.unifr.ch/documents/306103/files/luc_hat.pdf https://folia.unifr.ch/documents/306103/files/luc_hat_sm.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1021/acs.joc.7b00687 info:eu-repo/semantics/openAccess License undefined The Journal of Organic Chemistry. - 2017, vol. 82, no. 12, p. 6133–6141 info:eu-repo/classification/udc/54 Hydrogen atom transfer (HAT) processes promoted by the quinolinimide-N-oxyl radical: a kinetic and theoretical study http://purl.org/coar/resource_type/c_6501