Chiral Cross-Linked Covalent Organic Framework Films for Highly Sensitive Circularly Polarized Luminescence Probing

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Chirality Studies

Background:

• Developing covalent organic framework (COF) films for circular polarization luminescence (CPL) probing is challenging.
• Chiral sensing requires materials with high sensitivity and specificity for enantiomers.

Purpose of the Study:

• To create uniform and dense chiral COF films (chirCOFilms) for sensitive enantiomer detection.
• To explore the potential of these films in anticounterfeiting and chiral analysis.

Main Methods:

• Vapor-assisted epitaxial method to introduce axial chiral cross-linkers (R-/S-BBNA) into COF films.
• Chiral cross-linking reaction of COF films with R-/S-BBNA under UV irradiation.
• Preparation of chirCOFilm/PDMS flexible films and chiral photopatterns.

Main Results:

• Obtained chirCOFilms with strong chirality, mirror images, fluorescence discoloration, and intense CPL properties.
• Demonstrated advanced anticounterfeiting applications using photochromic properties.
• Achieved highly sensitive CPL probing of phenethylamine enantiomers at 5% concentration, surpassing fluorescence probing.

Conclusions:

• A novel strategy for preparing chiral COF films via chiral cross-linking reaction was developed.
• ChirCOFilms offer a new pathway for highly sensitive enantiomer detection using CPL.
• The study highlights the potential of chirCOFilms in advanced anticounterfeiting and chiral sensing.