[N⋯Br⋯N]⁺ Type Halogen Bonding: From Structure to Applications

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Chemistry

Background:

• Noncovalent halogen bonding, especially the [N⋯X⋯N]+ motif, is vital in supramolecular chemistry.
• I+-based systems are established, but [N⋯Br⋯N]+ motifs are gaining attention for their unique properties.

Purpose of the Study:

• To review the emerging [N⋯Br⋯N]+ motif in halogen-bonded organic frameworks (XOFs).
• To summarize synthetic strategies for stabilizing Br+ species.
• To highlight the advantages and applications of Br+-bridged XOFs.

Main Methods:

• Comprehensive literature review of synthetic strategies for [N⋯Br⋯N]+ motifs.
• Structural analysis of Br+-bridged XOFs.
• Performance evaluation in catalysis and biomedical applications.

Main Results:

• Synthetic strategies include spatial constraint, cation substitution, ligand exchange, and anionic regulation.
• The [N⋯Br⋯N]+ motif exhibits shorter N⋯Br bond lengths and enhanced electron deficiency.
• XOFs(Br) outperform I-analogues in alcohol oxidation, H2O2 production, antimicrobial activity, and photothermal therapy.

Conclusions:

• The [N⋯Br⋯N]+ motif offers significant advantages over I+-based systems.
• Stable Br+-bridged XOFs hold great potential for catalysis and precision medicine.
• This work paves the way for designing advanced functional materials using Br+-bridged XOFs.