Photoactivation of Solid-State Fluorescence through Controllable Intermolecular [2+2] Photodimerization

Area of Science:

• Materials Science
• Organic Chemistry
• Photochemistry

Background:

• Photoresponsive fluorescent materials offer dynamic control over optical properties.
• Intermolecular [2+2] photodimerization is a key reaction for creating novel molecular architectures.
• Developing solid-state fluorescent materials with tunable properties remains a significant challenge.

Purpose of the Study:

• To report efficient photoactivation of bright solid-state fluorescence.
• To utilize controllable intermolecular [2+2] photodimerization of benzo[b]thiophene 1,1-dioxide (BTO) derivatives.
• To construct smart photoresponsive solid-state fluorescent materials.

Main Methods:

• Synthesis of benzo[b]thiophene 1,1-dioxide (BTO) derivatives with rational substituent choices.
• Investigation of intermolecular [2+2] photodimerization triggered by light.
• Analysis of molecular stacking in crystals to control photodimerization.
• Characterization of solid-state fluorescence properties of BTO derivatives and their photodimers.

Main Results:

• Efficient photoactivation of bright solid-state fluorescence was achieved.
• Substituent engineering successfully regulated molecular stacking and photodimerization.
• Photodimers exhibited enhanced solid-state fluorescence and photostability.
• A novel method for synthesizing photostable aggregation-induced emission (AIE) materials via through-space conjugation was established.

Conclusions:

• Controllable intermolecular [2+2] photodimerization of BTO derivatives is an effective strategy for creating photoresponsive fluorescent materials.
• This approach enables the 'switching on' of solid-state fluorescence.
• The method provides a facile route to photostable AIEgens with unique electronic properties.