| Abstract
| - Considering the findings of Fujii et al. showing that the cis isomer of the o-cresol radical cation shows alow-frequency shift of the OH stretching attributed to an intramolecular hydrogen bond with the CH3 groupand considering the studies of Knak Jensen et al. concluding that such an O−H···C interaction was notpossible, the work presented in this article tries to understand if this is a consequence of the nature of thehydrogen bond acceptor (a CH3 group) or of the five-member ring that would be formed as a result of theintramolecular interaction. Thus, we have studied o-cresol, 8-methyl-1-hydroxynaphthalene, 1-hydroxy-1-propene, 1-hydroxy-3-methyl-1,3-butadiene, and their derivatives in which the −CH3 group has been substitutedby a −F atom or by an −OH group. Taking into account interaction distances and angles, interaction energies(from isodesmic reactions), and electron density characteristics, we can conclude that, in general, a methylgroup cannot behave as a hydrogen bond acceptor. In addition, we found that the formation of intramolecularhydrogen bonds driving to the formation of five-member rings is not favored even in the presence of a goodacceptor. Moreover, different methods of evaluating intramolecular interaction energies have been analyzed.
|
