Role of Polar and Enthalpic Effects in the Addition of Methyl Radical to Substituted Alkenes: A Density Functional Study Including Solvent Effects

详细信息    查看全文

• 作者：Roger Arnaud ; Nicolas Bugaud ; Valentina Vetere ; and Vincenzo Barone
• 刊名：Journal of the American Chemical Society
• 出版年：1998
• 出版时间：June 17, 1998
• 年：1998
• 卷：120
• 期：23
• 页码：5733 - 5740
• 全文大小：152K
• 年卷期：v.120,no.23(June 17, 1998)
• ISSN：1520-5126

文摘

The addition of methyl radical to mono- and disubstituted alkeneshas been studied by a hybridHartree-Fock/density functional method taking into account solventeffects by the polarizable continuummodel. The reliability of the electronic approach has beenverified by comparison with refined post-Hartree-Fock computations and with experimental data. Environmental effectsdo not alter the trends of in vacuocomputations due to the low dielectric constant of the solvent and tothe lack of significant charge separationeffects. Use of substrates characterized by captodative effectsand comparison with a genuine nucleophilicradical (CH₂OH) allow one to unequivocally concludethat CH₃ does not behave as a nucleophile. Asaconsequence polar effects are negligible and activation barriers aregoverned by the stability of the formingradical. These trends are confirmed by electron populationanalysis and evaluation of charge-transfer energies.