Evidence for the “Amphoteric” Nature of Fluorine in Halogen Bonds: An Instance of Cl···F Contact

This study presents unambiguous experimental evidence in support of the highly debated “halogen bond donor” character of organic fluorine. Two examples of intermolecular Cl···F contacts, with F-atom as halogen bond acceptor and donor, have been analyzed by in situ cryocrystallography and theoretical charge density studies.