Solvent Polarity Modulated Excited-State Dynamics within a Pyrene-Based Covalent Organic Cage
Xianyuan Wang1, Shanshan Liu2, Heyuan Liu1
1Shandong Key Laboratory of Intelligent Energy Materials, School of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, Shandong 266580, China.
The Journal of Physical Chemistry. A
|April 7, 2026
Summary
This study synthesized a covalent organic cage (PyTC1) with pyrene units, revealing how solvent polarity influences its excited-state dynamics and triplet state formation. These findings offer insights into solid-state photofunctional materials.
Area of Science:
- Materials Science
- Photochemistry
- Supramolecular Chemistry
Background:
- Establishing structure-property relationships in solid-state photofunctional materials is challenging.
- Covalent organic cages offer a tunable platform to mimic solid-state environments.
Purpose of the Study:
- To synthesize a [3 + 6]-type covalent organic cage (PyTC1) with three pyrene units.
- To investigate the excited-state dynamics of PyTC1 using transient spectroscopy.
- To understand the influence of solvent polarity on photophysical properties.
Main Methods:
- Synthesis of a [3 + 6]-type covalent organic cage (PyTC1).
- Transient spectroscopy techniques.
- Transient absorption spectroscopy.
Main Results:
- PyTC1 forms an H-type aggregate with strong intramolecular electronic coupling.
- Excited-state dynamics are solvent-polarity dependent.
- In low-polarity solvents, intersystem crossing (ISC) to the triplet state is enhanced.
- In high-polarity solvents, symmetry breaking charge separation (SB-CS) leads to a charge transfer state and delayed fluorescence.
Conclusions:
- Solvent polarity significantly impacts the excited-state dynamics of organic cages.
- Insights into the structure-property relationship for solid-state photofunctional materials were provided.
- The study highlights the role of ISC and SB-CS in controlling photophysical pathways.
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