Erlangen 2022 – scientific programme
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MO: Fachverband Molekülphysik
MO 11: Photochemistry I
MO 11.5: Talk
Wednesday, March 16, 2022, 11:30–11:45, MO-H7
Selenyl Radicals in Solution: Photogeneration and Reactions — •Carina Allacher1, Roger Jan Kutta1, Elias Harrer1, Daniel Grenda1, Amit Kumar-Dutta2, Sooyoung Park2, Alexander Breder2, and Patrick Nuernberger1 — 1Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93040 Regensburg — 2Institut für Organische Chemie, Universität Regensburg, 93040 Regensburg
Due to the low bond energy of selenium bonds, selenium-centered radicals can be formed photochemically with visible or near-UV light [1], thereby opening up new synthetic strategies based on the versatile reactivity of these radical species. A prominent precursor of the phenylselenyl radical (PhSe•) is diphenyl diselenide (Ph2Se2) which upon irradiation with UV light may dissociate homolytically [2].
In this work, we identify an additional reaction pathway that is pursued after excitation of Ph2Se2 with 355 nm light. To quantify the dynamics of these competing photochemical processes, transient absorption studies on a timescale from nano- to milliseconds are performed in various solvent environments. Solely in the solvent hexafluoro-2-propanol, a further intermediate, namely the radical PhSeH+•, can be photogenerated. Beyond Ph2Se2, we present time-resolved studies on further organoselenium compounds as light-triggered sources of PhSe• and PhSeH+• radicals.
[1] S. Ji et al., Angew. Chem. Int. Ed. 53, 6781 (2014).
[2] I. P. Beletskaya et al., J. Chem. Soc., Perkin Trans. 2, 107 (2007).