Fluoride Anions: Unexploited but Effective Halogen Bond Acceptors

Area of Science:

• Supramolecular Chemistry
• Crystal Engineering

Background:

• Fluoride anions possess high electron density, making them theoretically strong halogen bond acceptors.
• Hydration typically hinders fluoride's ability to participate in halogen bonding under standard conditions.

Purpose of the Study:

• To investigate the conditions under which fluoride can act as a halogen bond acceptor.
• To explore the role of fluoride-mediated halogen bonds in crystal structure formation.

Main Methods:

• Specific crystallization techniques were employed to isolate hydrogen bond-free fluoride species.
• Computational chemistry methods were used to analyze the strength of the formed halogen bonds.

Main Results:

• Achieved hydrogen bond-free fluoride capable of acting as an electron donor.
• Demonstrated that these fluoride-mediated halogen bonds are the primary driving force for observed crystal packings.
• Computational analysis confirmed the significant strength of these interactions.

Conclusions:

• Under specific conditions, fluoride can effectively participate in halogen bonding as an acceptor.
• Halogen bonds involving fluoride can be a dominant factor in directing crystal assembly.