Mhanna, Rana and Berger, Julia and Jourdain, Matthias and Muth, Stephan and Kutta, Roger Jan and Jung, Gregor (2025) Effect of Excitation Wavelength in Single-Molecule Photochemistry of Terrylene. CHEMPHYSCHEM, 26 (7): e202400996. ISSN 1439-4235, 1439-7641
Full text not available from this repository. (Request a copy)Abstract
The reaction of terrylene in p-terphenyl with molecular oxygen is reinvestigated by TIRF-microscopy with lambda(exc)=488 nm or lambda(exc)=561 nm and 488 nm. A similar range of fluorescent products is obtained under both experimental conditions with a reaction quantum yield Phi(r)>10(-7) for those molecules which undergo the photoreaction. The majority of these oxygen-susceptible molecules reacts via an electronically relaxed, dark intermediate, presumably an endoperoxide, with a lifetime of <t(off)>similar to 20 s. From this time constant, an activation energy E-A<0.8 eV is estimated for the transition from the intermediate to the final product, the diepoxide, which nicely agrees with values calculated for the terrylene-derivative TDI. However, similar to 20 % of all reacting molecules at lambda(exc)=561 nm and even similar to 40 % at lambda(exc)=488 nm show an immediate change of the fluorescence colour within the time resolution of the experiment, bypassing any dark intermediate. Based on this experimentally observed impact of the excitation energy and the lack of relevant excited-state absorption, we hypothesize that oxygen forms a complex with ground-state terrylene which then undergoes a quasi-unimolecular reaction in the excited-state before vibrational relaxation takes place.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | INDIVIDUAL MOLECULES; P-TERPHENYL; OXYGEN; SPECTROSCOPY; ABSORPTION; EMISSION; GREEN; RED; fluorescence spectroscopy; single-molecule studies; singlet oxygen; cycloaddition |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 07 May 2026 05:14 |
| Last Modified: | 07 May 2026 05:14 |
| URI: | https://pred.uni-regensburg.de/id/eprint/66743 |
Actions (login required)
 |
View Item |
