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The Magnitude of Hyperconjugation in Ethane: A Perspective from Ab Initio Valence Bond Theory

2004; Wiley; Volume: 43; Issue: 15 Linguagem: Inglês

10.1002/anie.200352931

1521-3773

Yirong Mo, Wei Wu, Lingchun Song, Menghai Lin, Qianer Zhang, Jiali Gao,

Catalysis and Oxidation Reactions

Steric effect dominates: Ab initio valence bond and block-localized wavefunction methods are used to estimate the contributions of hyperconjugation and steric effects to the ethane rotation barrier. The results show that hyperconjugation stabilizes the staggered conformer by about 4 kJ mol−1 relative to the eclipsed form (see picture) and steric hindrance is the major driving force behind the favoring of the staggered conformation in ethane.