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Excitonic Hamiltonians for Calculating Optical Absorption Spectra and Optoelectronic Properties of Molecular Aggregates and Solids
Published on: May 27, 2020
Bonded exciplex formation: electronic and stereoelectronic effects
Yingsheng Wang1, Olesya Haze, Joseph P Dinnocenzo
1Department of Chemistry and Center for Photoinduced Charge Transfer, University of Rochester, Rochester, New York 14627, USA.
The Journal of Physical Chemistry. A
|October 25, 2008
Summary
Researchers explored bonded exciplex formation in photochemical reactions. Electronic and steric effects influence quenching rates, supporting this novel charge transfer model, even with dioxane.
Area of Science:
- Photochemistry
- Organic Chemistry
- Physical Chemistry
Background:
- Bonded exciplexes represent a novel mechanism in photochemical charge transfer reactions.
- Understanding factors influencing their formation is crucial for advancing photochemistry.
Purpose of the Study:
- To investigate electronic and steric effects on bonded exciplex formation rates.
- To explore the behavior of bonded exciplexes in polymer matrices.
- To demonstrate competing reaction pathways and expand the scope of bonded exciplexes.
Main Methods:
- Kinetic studies of cyanoaromatics reacting with pyridine derivatives.
- Spectroscopic analysis of excited-state quenching.
- Computational modeling to support experimental observations.
- Investigation of reactions involving poly(vinylpyridine) and dioxane.
Main Results:
- Electronic and steric factors significantly impact quenching rate constants, supporting the bonded exciplex model.
- Excited-state quenching in poly(vinylpyridine) is inhibited compared to neat pyridine, indicating specific orientational requirements.
- Evidence for bonded exciplex formation between 2,6,9,10-tetracyanoanthracene (TCA) and dioxane was observed, expanding the known scope of these complexes.
- Competing reactions forming conventional and bonded exciplexes were analyzed, highlighting the energetic balance.
Conclusions:
- The study provides strong support for the bonded exciplex model in photochemical charge transfer.
- Restrictive orientational requirements are key for bonded exciplex formation, particularly in polymer systems.
- The scope of bonded exciplexes has been expanded to include oxygen-substituted donors like dioxane.
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