Fluorine Lewis Acids

When R is sufficiently electron withdrawing, the fluorine in the R-F molecules could interact with electrondonors (e.g. ammonia) and form a non-covalent bond (F⋯N). Inasmuch as there are fundamental differences betweenthese interactions and halogen bonds of iodine, bromine and chlorine, the term fluorine bond is preferred fordescribing these type of interactions. Natural energy decomposition analysis (NEDA) and interacting quantum atoms(IQA) methods reveal that fluorine and halogen bonds are different in their geometrical preference. In contrast to thehalogen bonds (R − X ⋯ Y) that are highly directional and the R − X − Y angle tends to be linear, fluorine bonds are notdirectional.

Keywords:

Fluorine bond , Halogen bond , Directionality , IQA , NEDA