Conformational analysis. Part 35.1NMR, solvation and theoretical investigation of rotational isomerism in methyl fluoroacetate and methyl difluoroacetate
Abstract
The O 0°) and trans (F–C–C
O 180°) conformers of ca. equal energy. The gauche conformer was not a minimum in the energy surface. The
) between the cis and trans conformers of 0.90 kcal mol−1 in the vapour phase, decreasing to 0.41 kcal mol−1 in
O 0°) and gauche (H–C–C
O 141.9°) conformers with an energy difference (Ecis − Egauche
) of 0.2 kcal mol−1. The
) between the cis and gauche conformers of 0.0 kcal mol−1 in the vapour phase, increasing to 0.46 kcal mol−1 in