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How Do Molecular Motions Affect Structures and Properties at Molecule and Aggregate Levels?
Deshuang Tu1, Jianyu Zhang1, Yunxiao Zhang1
1Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China.
Journal of the American Chemical Society
|July 22, 2021
Summary
This study reveals how molecular motions influence material properties across different scales. It demonstrates that controlling molecular motion in aggregation-induced emission (AIE) materials enables tunable luminescence and robust, elastic crystals.
Area of Science:
- Materials Science
- Organic Chemistry
- Supramolecular Chemistry
Background:
- Molecular motions are fundamental to material properties but challenging to study across structural hierarchies.
- Aggregation-induced emission (AIE) luminogens offer a unique platform to investigate motion-structure-property relationships.
Purpose of the Study:
- To design and synthesize novel AIE luminogens (PyCz, ClPyCz, BrPyCz, CyPyCz) to understand how molecular motions dictate structure and properties at molecular and aggregate levels.
- To explore the impact of intramolecular and intermolecular motions on emission characteristics and mechanical behavior.
- To develop a paradigm for designing multifunctional AIE materials.
Main Methods:
- Synthesis of pyrimidine-carbazole based AIE luminogens.
- Experimental characterization including spectroscopy and structural analysis.
- Theoretical calculations to elucidate excited-state dynamics and conformational changes.
- Investigation of mechanical properties and deformation behavior of crystalline materials.
Main Results:
- Single-molecule level: Active intramolecular motions lead to twisted conformations and weak emission.
- Aggregate level: Restricted intramolecular motions result in less twisted conformations and bright AIE.
- Macroaggregate level: Activated intermolecular motions in specific crystals (ClPyCz, BrPyCz, CyPyCz) enable reversible deformation and excellent elastic performance, overcoming organic crystal brittleness.
Conclusions:
- Established a comprehensive understanding of motion-structure-property relationships in AIE materials from single molecules to macrocrystals.
- Demonstrated that controlling molecular and intermolecular motions is key to designing materials with tunable luminescence and enhanced mechanical properties.
- Provided a new strategy for creating robust, elastic organic materials with potential applications in advanced technologies.
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