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Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
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Revisiting fluorenone photophysics via dipolar fluorenone derivatives
Leandro A Estrada1, James E Yarnell, Douglas C Neckers
1Center for Photochemical Sciences at Bowling Green State University, Bowling Green, Ohio 43403, United States.
The Journal of Physical Chemistry. A
|May 20, 2011
Summary
Nonradiative decay in fluorenone derivatives (FODs) was studied. Carbazole-containing FODs primarily use charge separation/recombination, while 3,6-disubstituted variants show intersystem crossing (ISC).
Area of Science:
- Photochemistry
- Organic Chemistry
- Computational Chemistry
Background:
- Fluorenone derivatives (FODs) are important organic molecules.
- Understanding nonradiative decay pathways is crucial for designing new materials.
Purpose of the Study:
- To investigate the nonradiative decay mechanisms of four dipolar fluorenone derivatives (FODs).
- To elucidate the role of substituents and solvent polarity on excited state deactivation pathways.
Main Methods:
- Steady-state and time-resolved UV-vis absorption and fluorescence spectroscopy.
- Cyclic voltammetry.
- Density Functional Theory (DFT) calculations for frontier orbital analysis.
Main Results:
- The first singlet excited state was identified as π-π* across all FODs and solvent polarities.
- Charge separation/recombination dominated excited state deactivation in carbazole-containing FODs.
- Intersystem crossing (ISC) was the exclusive deactivation pathway in 3,6-disubstituted FODs, competing with charge transfer (CT) in CPAFO36.
Conclusions:
- Nonradiative decay in FODs is highly dependent on molecular structure and substitution patterns.
- ISC is a significant deactivation pathway for 3,6-disubstituted FODs.
- The findings provide insights into controlling photophysical properties of fluorenone derivatives.
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