Theoretical Study of the Reaction Mechanisms Involved in the Thermal Intramolecular Reactions of 1,6-Fullerenynes

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• 作者：Mireia Gü ; ell ; Nazario Martí ; n ; Margarita Altable ; Salvatore Filippone ; Á ; ngel Martí ; n-Domenech ; Miquel Sol&agrave
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：June 21, 2007
• 年：2007
• 卷：111
• 期：24
• 页码：5253 - 5258
• 全文大小：387K
• 年卷期：v.111,no.24(June 21, 2007)
• ISSN：1520-5215

文摘

Substitution of a H atom by an alkyl group on the terminal carbon of the alkyne moiety of 1,6-fullerenyneshas a strong impact on the products of the reaction undergone by this species after thermal treatment. Whilethe reaction of 1,6-fullerenynes bearing an unsubstituted alkyne moiety results in the cycloaddition of thealkyne group to the fullerene double bond leading to cyclobutene-fused derivatives, the presence of an alkylsubstituent leads to the formation of allenes. In the present work, we have performed an exhaustive theoreticalanalysis of all possible reaction mechanisms leading to cyclobutene-fused derivatives and allenes to offer anexplanation of the reactivity differences observed. The results obtained show that formation of cyclobutene-fused derivatives occurs through a stepwise diradical reaction mechanism, while allene formation proceedsthrough a concerted way involving an uncommon intramolecular ene process. For the 1,6-fullerenynes bearinga substituted alkyne, the ene reaction path leading to allenes has an energy barrier somewhat lower than thestepwise diradical mechanism for the cyclobutene-fused derivative formation, thus explaining the outcome ofthe reaction.