Theoretical study of the Diels-Alder reactions between singlet (1Delta g) oxygen and acenes.
The G3(MP2) method has been employed to study the 1,4-addition reactions between singlet oxygen and five acenes, including benzene, naphthalene, anthrecene, tetracene, and pentacene. In all, nine pathways between O(2) and the five acenes have been investigated. Our calculated results indicate that all nine pathways are concerted and exothermic and that the most reactive sites on the acenes are the center ring's meso-carbons. In addition, reactivity increases along the series benzene < naphthalene < anthrecene < tetracene < pentacene. This trend is identical to that of aromaticity for the five acenes. A correlation between reactivity and aromaticity is briefly rationalized with natural bond orbital (NBO) analysis and frontier molecular orbital (FMO) analysis. Furthermore, some experimental kinetics data from the literature supporting the calculated results are cited.
Chien
Siu-Hung
SH
Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong.
Cheng
Mei-Fun
MF
Lau
Kai-Chung
KC
Li
Wai-Kee
WK