SAMOP 2023 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 2: Photochemistry
MO 2.2: Vortrag
Montag, 6. März 2023, 11:15–11:30, F142
Unraveling the photochemistry of TiIV(Cp)2(NCS)2 — •Jonas Schmidt, Luis Ignacio Domenianni, and Peter Vöhringer — University of Bonn, DE
Recently, the complex, Cp2Ti(Cl)2, has been used as a photo-redox-catalyst for atom economical transformations in one-electron steps.[1] We investigated the initial excitation and quenching of the catalyst using time-correlated single-photon-counting and femtosecond ultraviolet-pump mid-infrared-probe spectroscopy (UVmIR). The chlorido ligands were substituted with isothiocyanato ligands to render the catalyst amenable to UVmIR.
We recorded the emission spectrum and determined luminescence lifetimes of Cp2Ti(NCS)2 in liquid tetrahydrofuran solution at room temperature. The bi-exponential nature of the luminescence decay is highly indicative of thermally activated delayed fluorescence in addition to prompt fluorescence from the optically prepared singlet excited state. The triplet state was successfully quenched with triphenylamine and a Stern-Vollmer quenching constant of 9.4x109 L/mol s was determined
UVmIR data obtained continuously from 50 femtoseconds to several microseconds supported this interpretation and the vibrational signatures of the S1- and T1-states were obtained by performing a target analysis of the time- and frequency-dependent pump-probe data set.
References:
[1] Z. H. Zhang et al., Angew. Chem. Int. 2020, 59, 9355–9359.