Enhancing Fluorescence in Both Solution and Solid States Induced by Imine Cage Formation.

Area of Science:

• Materials Science
• Organic Chemistry
• Supramolecular Chemistry

Background:

• Developing luminescent materials with strong emission in both solution and solid phases is a significant challenge.
• Existing materials often suffer from aggregation-caused quenching in the solid state or weak emission in solution.

Purpose of the Study:

• To design and synthesize a rigid organic cage for confinement-induced fluorescence enhancement.
• To demonstrate a single-step synthetic strategy for creating highly emissive luminescent materials.

Main Methods:

• Synthesized a tetraphenylethylene-cored tetra-aldehyde (TPE-TA) and a clip-like diamine (XA).
• Utilized [2+4] imine condensation to form the rigid TPE-cage.
• Characterized the photophysical properties of the TPE-cage in solution and aggregated states.

Main Results:

• The TPE-cage exhibited a ~520-fold emission enhancement in dichloromethane solution compared to the non-emissive TPE-TA.
• A control TPE-model compound showed only minor emission enhancement, highlighting the cage effect.
• Further ~1.5-fold emission enhancement was observed in the aggregated state due to aggregation-induced emission enhancement (AIEE).

Conclusions:

• Imine-bond directed formation of rigid organic cages effectively enhances fluorescence.
• This strategy provides a facile route to luminescent materials with superior performance in both solution and solid states.
• The developed TPE-cage demonstrates significant potential for advanced luminescent material applications.