Application of Radical Cation Spin Density Maps toward the Prediction of Photochemical Reactivity between N-Methyl-1,2,4-triazoline-3,5-dione and Substituted Benzenes

Autor:	Kevin R. Hoke, Gary W. Breton
Rok vydání:	2013
Předmět:	Substitution reaction Free Radicals Light Molecular Structure Chemistry Organic Chemistry Visible light irradiation Triazoles Photochemical Processes Ring (chemistry) Photochemistry Photoexcitation Radical ion Cations Benzene Derivatives Quantum Theory Photochemical reactivity Spin density
Zdroj:	The Journal of Organic Chemistry. 78:4697-4707
ISSN:	1520-6904 0022-3263
DOI:	10.1021/jo4001417
Popis:	Visible light irradiation of N-methyl-1,2,4-triazoline-3,5-dione in the presence of substituted benzenes is capable of inducing substitution reactions where no reaction takes place thermally. In addition to the formation of 1-arylurazole products resulting from ring substitution, side-chain substitution occurs in some cases where benzylic hydrogens are accessible to form benzylic urazole products. Formation of both types of products is most consistent with the involvement of a common intermediate, a radical ion pair, generated from photoexcitation of an initially formed charge-transfer complex. The charge-transfer complexes have been observed spectroscopically. Additionally, application of a modified Rehm-Weller model suggests that the electron-transfer processes are feasible for all of the substrates examined. In most cases, the spin density maps of the aromatic radical cation intermediates calculated at the DFT UB3LYP/6-31G* level are excellent predictors of the observed product distributions.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c3ed14ab6049c54abb4ed367592c6d79 https://doi.org/10.1021/jo4001417 Zobrazit plný text záznamu