A switchable red-emitting fluorophore involving a 7.6.6 defect

Area of Science:

• Supramolecular Chemistry
• Organic Fluorophore Design
• Photophysics

Background:

• Macrocyclic compounds offer unique structural control.
• Acridine derivatives are known for their photoluminescent properties.
• Controlling fluorescence via external stimuli is crucial for sensor development.

Purpose of the Study:

• To design and synthesize a novel macrocyclic derivative incorporating an acridine unit.
• To investigate the photophysical properties of the resulting fluorophore.
• To explore the mechanism of fluorescence quenching and on/off switching behavior.

Main Methods:

• Synthesis of a macrocyclic derivative with a 7.6.6 defect structure.
• Spectroscopic analysis (UV-Vis absorption, fluorescence emission).
• Computational modeling to understand electronic interactions.

Main Results:

• The designed molecule exhibits efficient fluorescence.
• The internal cavity and rigid macrocycle enable tunable optical properties.
• Hydrogen-like interactions were identified as the primary mechanism for fluorescence quenching, facilitating on/off switching.

Conclusions:

• Entangling an acridine unit into a rigid macrocycle creates a highly efficient and switchable fluorophore.
• The unoccupied cavity plays a critical role in modulating photophysical behavior.
• Hydrogen-like interactions are key to controlling emission in these organic chromophores.