Freiburg 2024 – scientific programme

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MO: Fachverband Molekülphysik

MO 21: Ultrafast Dynamics II

MO 21.2: Talk

Thursday, March 14, 2024, 14:45–15:00, HS 3044

Unraveling the photochemistry of Ti^IVCp2(NCS)2 — •Jonas Schmidt, Luis Ignacio Domenianni, Marcel Leuchner, Andreas Gansäuer, and Peter Vöhringer — Rheinische Friedrich-Wilhelms-Universität, Bonn, Deutschland

Recently, we reported the observation of the entry event of Ti^IVCp2(NCS)2 into a photocatalytic cycle in real-time.^[1] In this study we were able to show the thermally activated delayed fluorescence of Ti^IVCp2(NCS)2 after excitation with 450 nm light. Furthermore, we were able to observe the reductive quenching of the reactive triplet state with NPh3 as an electron donor using time-resolved spectroscopy.

In a further step, we now want to investigate the following steps in the catalytic cycle. Therefore, we employ a substrate that acts as the amine electron donor to reduce the titanocene as well as the epoxide for radical arylation. To achieve this goal, we will utilize the long pump-probe delays of up to 300 µs of our synchronized double Ti:Sapphire regenerative amplifier setup for fs-UV/Vis-pump/mIR-probe spectroscopy. To aid the analysis of the spectroscopic findings, we will employ density functional theory as well as cooperate with synthetic chemists. From these experiments, we hope to gain further insight into the later mechanism of the photocatalytic cycle as it is still unclear if one or two equivalents of the substrate are involved.

Literature:

[1] J. Schmidt et al., Angew. Chem. Int. Ed. 2023, 62, e202307178.

Keywords: ultrafast infrared spectroscopy; photo-redox catalysis; thermally activated delayed fluorescence; transition-metal photochemistry