Wavelength-tunable AIEgens based on 6-methoxy-2-naphthaldehyde: AIE behavior and bioimaging performance

Area of Science:

• Materials Science
• Organic Chemistry
• Biotechnology

Background:

• Aggregation-induced emission (AIE) dyes are crucial for advanced applications like bioimaging and theranostics.
• Developing novel AIE fluorophores with enhanced properties is an active area of research.

Purpose of the Study:

• To synthesize novel AIE-active fluorophores using 6-methoxy-2-naphthaldehyde via Knoevenagel condensation.
• To investigate the photophysical properties and bioimaging capabilities of the synthesized compounds, particularly MOP-e.

Main Methods:

• Knoevenagel condensation reaction between 6-methoxy-2-naphthaldehyde and active methylene compounds.
• Characterization of photophysical properties including AIE characteristics, redshift, and Stokes shift.
• Single crystal X-ray diffraction analysis to understand molecular packing.
• In vitro bioimaging experiments in living cells.

Main Results:

• Several AIE-active fluorophores were successfully synthesized.
• MOP-e exhibited significant redshift, large Stokes shift, and an ultra-wide AIE band upon aggregation.
• Single crystal analysis revealed monomolecular and discrete π-π dimeric stacking modes in MOP-e aggregates.
• Discrete dimeric stacking was identified as the cause of excimer-induced enhanced emission and unique AIE behavior.
• MOP-e demonstrated excellent dual-channel (green and red) bioimaging performance in living cells.

Conclusions:

• The synthesized fluorophores, especially MOP-e, possess promising AIE characteristics.
• MOP-e's unique aggregation-induced emission mechanism and dual-channel imaging capability make it a valuable tool for bioimaging.
• This study expands the toolkit of AIE dyes for sophisticated biological applications.