Revealing the Polarizability of Organic Fluorine in the Trifluoromethyl Group: Implications in Supramolecular Chemistry

The
experimental evidence for the polarization of the electron
density on the fluorine atom of the trifluoromethyl group in the crystal
results in the formation of an electron deficient region. This facilitates
F···F halogen bond formation along with the subsequent
presence of “short” C–H···F intermolecular
contacts (rare geometry) which are a significant electronic and structural
feature. This study proves that such an interaction has a substantial
“electrostatic contribution”. It breaks the long-accepted
lore that “organic fluorine is not polarizable”.