Density functional study of the one-bond C-F coupling constant in alpha-fluorocarbonyl and alpha-fluorosulfonyl compounds

作者：Freitas Matheus P^*; Buehl Michael

来源：Journal of Fluorine Chemistry, 2012, 140: 82-87.

DOI：10.1016/j.jfluchem.2012.05.007

• (1)J(CF) coupling constant
• alpha-Fluorocarbonyl
• alpha-Fluorosulfonyl
• Dipolar interactions
• Hyperconjugation

(1)J(CF) coupling constants of alpha-fluorocarbonyl and alpha-fluorosulfonyl model compounds are analyzed at the BHandH/EPR-III level of density functional theory. For fluoroethanal, (1)J(CF) follows the electrostatic-based behavior exhibited by 1,2-difluoroethane, whereas for (fluoromethyl)sulfone, hyperconjugation is indicated to be important as well. The variation of (1)J(CF) during rotation about the C-S bond parallels that of the n(F) --%26gt; sigma(CS)* donor-acceptor interaction, which is a result of the better electron acceptor ability of the sigma(CS(O2))* orbital when compared to the corresponding sigma(CC(O))* orbital of alpha-fluorocarbonyl compounds. Because the rotational profile of (1)J(CF) is non-monotonic in (fluoromethyl)sulfone, this coupling constant is indicated to be of limited diagnostic value to probe the conformations of alpha-fluorosulfones.

• 出版日期2012-8