Controllable aggregation-induced emission based on a tetraphenylethylene-functionalized pillar[5]arene via host-guest...

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Fluorescent Materials

Background:

• Aggregation-Induced Emission (AIE) is a phenomenon where luminogens are non-emissive in solution but become highly fluorescent in the aggregated state.
• Pillararenes are macrocyclic hosts known for their host-guest complexation abilities, offering potential for molecular recognition and material design.
• Tetraphenylethylene (TPE) is a well-known AIE-active luminogen whose fluorescence is sensitive to molecular environment and aggregation.

Purpose of the Study:

• To synthesize a novel supramolecular material combining TPE and pillar[5]arene functionalities.
• To investigate the effect of host-guest interactions on the photophysical properties of TPE.
• To achieve controlled fluorescence enhancement through molecular design and supramolecular assembly.

Main Methods:

• Synthesis of tetraphenylethylene-functionalized pillar[5]arene (TPEP5).
• Host-guest complexation studies to investigate molecular recognition between TPEP5 components.
• Fluorescence spectroscopy to monitor emission changes upon complexation and cross-linking.
• Analysis of the mechanism controlling fluorescence based on the AIE effect.

Main Results:

• Successful synthesis of the TPEP5 molecule.
• Demonstration of host-guest recognition-mediated restriction of TPE motif motion within the pillararene cavity.
• Observation of efficient 'turn-on' fluorescence emission, confirming the AIE mechanism.
• The cross-linking strategy effectively suppressed non-radiative decay pathways, enhancing luminescence.

Conclusions:

• The study presents a novel TPE-functionalized pillar[5]arene (TPEP5) with controllable fluorescence.
• Host-guest recognition is a viable strategy to restrict molecular motion and activate AIE.
• This work provides a new avenue for designing advanced fluorescent materials based on supramolecular self-assembly.