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”.