Artmann, Kevin and Pollok, Corina H. and Merten, Christian and Nuernberger, Patrick (2022) Wavelength-dependent photochemistry of a salicylimine derivative studied with cryogenic and ultrafast spectroscopy approaches. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 24 (48). pp. 30017-30026. ISSN 1463-9076, 1463-9084
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Salicylimines are versatile compounds in which an excited-state intramolecular proton transfer and torsional motions may set in upon photoexcitation. Here, we study N-(alpha-phenylethyl)salicylimine (PESA) to elucidate how the photochemical reaction pathways depend on the excitation wavelength and to what extent the relative photoproduct distribution can be steered towards a desired species. DFT structure and potential energy calculations disclose that the most stable ground-state conformer is an enol species and that the photodynamics may proceed differently depending on the excited state that is reached. With matrix isolation infrared spectroscopy, the predominance of the enol conformer of PESA is confirmed. Illumination of the cryogenic sample with different wavelengths shifts the ratio of enol and keto products, and by sequential irradiation a selective re- and depopulation is possible. Femtosecond transient absorption spectroscopy further reveals that also at room temperature, the outcome of the photoreaction depends on excitation wavelength, and in combination with the calculations, it can be rationalized that the decisive step occurs within the first hundred femtoseconds. Since the ultrafast dynamics mostly match those of similar salicylimines, our findings might also apply to those systems and provide additional insight into their reported sensitivity on excitation energy.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | INTRAMOLECULAR PROTON-TRANSFER; FEMTOSECOND TRANSIENT ABSORPTION; PHOTOCHROMIC SCHIFF-BASES; EXCITED-STATE DYNAMICS; SALICYLIDENEANILINE SA; PHOTOINDUCED PROCESSES; SINGLET-STATE; FLUORESCENCE; PHOTOPHYSICS; ANILINE |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Chair of Physical Chemistry I > Prof. Dr. Patrick Nürnberger |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 07 Feb 2024 10:37 |
| Last Modified: | 07 Feb 2024 10:37 |
| URI: | https://pred.uni-regensburg.de/id/eprint/57248 |
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