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Updated: Jun 10, 2025
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Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
Published on: November 29, 2018
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Intramolecular benzene excimer formation in 13,14-diphenyldibenzo[b,j][4,7]phenanthroline
Jiafen Lin1, Lin Ma2, Yilun Zhao2
1State Key Laboratory of Fine Chemicals, Frontiers Science Center for Smart Materials, Dalian University of Technology, Dalian 116024, China.
The Journal of Chemical Physics
|October 14, 2024
Summary
13,14-diphenyldibenzo[b,j][4,7]phenanthroline (DBP3) forms an intramolecular benzene excimer, leading to redshifted emission. This process involves rapid fluorescence quenching and relaxation via hot excimer states, influenced by solvent interactions.
Area of Science:
- Photochemistry
- Spectroscopy
- Organic Chemistry
Background:
- 13,14-diphenyldibenzo[b,j][4,7]phenanthroline (DBP3) is a complex organic molecule with potential applications in optoelectronics.
- Understanding its excited-state dynamics is crucial for designing efficient light-emitting materials.
Purpose of the Study:
- To investigate the excited-state dynamics of DBP3 in various solvents.
- To elucidate the mechanism of intramolecular excimer formation and its influence on fluorescence.
- To characterize the relaxation pathways and triplet state formation.
Main Methods:
- Time-resolved fluorescence spectroscopy
- Femtosecond transient absorption (fs-TA) spectroscopy
Main Results:
- Demonstrated the formation of an intramolecular benzene excimer in DBP3, exhibiting redshifted emission (540-640 nm).
- Observed dramatic quenching of intrinsic DBP3 fluorescence (τ = 50-400 fs) due to excimer formation.
- Identified three lifetime components (50 fs, ~3.5 ps, ~25 ps) for relaxed intramolecular benzene excimer formation from the S1 state via a hot excimer state, attributed to inertial and diffusive relaxation influenced by solute-solvent interactions.
- Directly observed the formation of triplet states via intersystem crossing from upper excited electronic states of DBP3.
Conclusions:
- DBP3 undergoes rapid intramolecular benzene excimer formation, significantly altering its photophysical properties.
- Solute-solvent interactions play a critical role in the relaxation dynamics of the excited states.
- The study provides insights into the complex photochemistry of DBP3, relevant for molecular design in materials science.
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