Polymorphic Pure Organic Luminogens with Through-Space Conjugation and Persistent Room-Temperature Phosphorescence.

Area of Science:

• Materials Science
• Organic Chemistry
• Photophysics

Background:

• Pure organic luminogens with persistent room-temperature phosphorescence (p-RTP) are crucial for applications like security inks and bioimaging.
• Existing p-RTP materials typically rely on through-bond conjugation.

Purpose of the Study:

• To report a novel pure organic luminogen, AN-MA, utilizing through-space conjugation.
• To investigate the photophysical properties, including aggregation-enhanced emission (AEE) and p-RTP, of AN-MA.

Main Methods:

• Synthesis of AN-MA via Diels-Alder cycloaddition of anthracene (AN) and maleic anhydride (MA).
• Characterization of AN-MA's optical properties, including fluorescence and phosphorescence in solution and crystalline states.
• Polymorph analysis of AN-MA.

Main Results:

• AN-MA exhibits aggregation-enhanced emission (AEE) with efficiencies up to 8.5% in crystals.
• Two polymorphs of AN-MA were obtained, showing UV and blue emission due to through-space conjugation.
• Persistent room-temperature phosphorescence (p-RTP) with a lifetime up to 1.65s was observed in crystals.

Conclusions:

• AN-MA represents a new class of organic luminogen with dual fluorescence and RTP emission.
• The study demonstrates the potential of through-space conjugation for developing novel pure organic p-RTP materials with tunable emissions.