Luminescent MOFs constructed by using butterfly-like AIE ligands

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Organic Chemistry

Background:

• Aggregation-induced emission (AIE) is a phenomenon where molecules exhibit enhanced luminescence upon aggregation.
• Metal-organic frameworks (MOFs) are porous materials with diverse applications, including luminescence.
• The design of novel AIEgens and their integration into functional materials like MOFs is an active research area.

Purpose of the Study:

• To synthesize novel butterfly-like oxacalix[2]naphthalene[2]pyrazine (ONP) isomers.
• To investigate the aggregation-induced emission (AIE) properties and mechanism of the synthesized ONPs.
• To construct luminescent metal-organic frameworks (MOFs) using ONPs as ligands and explore their characteristics.

Main Methods:

• One-step, catalyst-free synthesis of oxacalix[2]naphthalene[2]pyrazine (ONP) isomers.
• Characterization of AIE properties through photoluminescence spectroscopy.
• Mechanism study focusing on restriction of intramolecular vibration (RIV).
• Construction and characterization of three ONP-based luminescent MOFs.

Main Results:

• A series of butterfly-like ONP isomers were successfully synthesized.
• ONPs exhibit typical aggregation-induced emission (AIE) properties, attributed to the restriction of intramolecular vibration (RIV).
• Three luminescent MOFs were constructed using ONPs, showing intense emission with microsecond lifetimes.
• The conformation of ONP isomers dictates their binding capacity, leading to selective MOF formation even from isomer mixtures.

Conclusions:

• This work introduces a new class of RIV-type AIEgens based on ONP structures.
• The study demonstrates the potential of ONPs as versatile ligands for constructing luminescent MOFs.
• The findings highlight the critical role of molecular conformation in ligand design for MOF applications.