Dynamic Hydrogen-Bonding Switching Enables Crystal Transformation for Multi-Stimuli Responsive Fluorescence

Area of Science:

• Materials Science
• Supramolecular Chemistry
• Organic Chemistry

Background:

• Controlling solid-state structural transitions in organic cocrystals for stimulus-responsive luminescence is challenging.
• Developing materials with tunable optical properties is crucial for advanced applications.

Purpose of the Study:

• To design and synthesize organic cocrystal systems with reversible crystal transformation and stimulus-responsive luminescence.
• To investigate the role of dynamic hydrogen-bond switching in controlling cocrystal behavior.

Main Methods:

• Synthesis of conformationally adaptive V-shaped molecules (26PY, 35PY, 13PH) acting as electron donors.
• Formation of cocrystals using hydrogen-bond acceptors like water, DMF, DMSO, TCNB, and DNB.
• Mechanical grinding and thermal treatment to induce crystal phase transitions and luminescence changes.

Main Results:

• Achieved reversible crystal transformation and stimulus-responsive luminescence through dynamic hydrogen-bond switching.
• Identified hydrated intermediates and binary/ternary cocrystal formation based on solvent interactions.
• Demonstrated tunable fluorescence in cocrystals with various nitroaromatic compounds.

Conclusions:

• The developed cocrystal systems exhibit controllable structural transitions and luminescence.
• This strategy offers a pathway for creating novel smart materials for sensing and anti-counterfeiting applications.
• Highlights the potential of dynamic hydrogen bonding in designing responsive supramolecular materials.