DFT study of the 1JCF coupling constant in XCHFX fragments (XÂ =Â O and S)

2-Fluoro-1,3-dioxane and 2-fluoro-1,3-dithiane exhibit the reverse fluorine Perlin-like effect, which was found to be affected by multiple effects, including the interaction between F and O/S electron lone pairs, hyperconjugation and dipolar effects.