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Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
Published on: June 10, 2021
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.
Abstract:
The nonradiative decay of four dipolar fluorenone derivatives (FODs) was systematically investigated using steady state and time-resolved UV-vis absorption and fluorescence measurements combined with cyclic voltammetry. Analysis of the frontier orbital localization of the global minimum geometry and the vertical transitions was carried out from DFT calculations. The first singlet excited state was found to be π-π* in all derivatives regardless of the polarity of the solvent. Charge separation/recombination dominates the singlet excited state deactivation for carbazole-containing FODs. Intersystem crossing (ISC) operates exclusively in the 3,6-disubstituted variants as evidenced by phosphorescence experiments. In the case of CPAFO36, ISC competes disadvantageously with CT deactivation.
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