Abstract
Corroles are a developing class of tetrapyrrole-based molecules with significant chemical potential and relatively unexplored photophysical properties. We combined femtosecond broadband fluorescence up-conversion and fs broadband Vis-pump Vis-probe spectroscopy to comprehensively characterize the photoreaction of 5,10,15-tris-pentafluorophenyl-corrolato-antimony(V)-trans-difluoride (Sb-tpfc-F2). Upon fs Soret band excitation at ~400 nm, the energy relaxed almost completely to Q band electronic excited states with a time constant of 500 ± 100 fs; this is evident from the decay of Soret band fluorescence at around 430 nm and the rise time of Q band fluorescence, as well as from Q band stimulated emission signals at 600 and 650 nm with the same time constant. Relaxation processes on a time scale of 10 and 20 ps were observed in the fluorescence and absorption signals. Triplet formation showed a time constant of 400 ps, with an intersystem crossing yield from the Q band to the triplet manifold of between 95% and 99%. This efficient triplet formation is due to the spin-orbit coupling of the antimony ion.
Highlights
Corroles are a developing class of tetrapyrrole-based photosensitizers with relatively unexplored photophysical properties [1,2,3,4]
Soret band to band transition in agreement to the decay of the stimulated emission (SE) and the excited state absorption (ESA) of the Soret band, and rise of the ESA ofwith our the Q band. It was demonstrated the Q band of the corroles consists of two singletsignals excited states time-resolved fluorescence data
Our data presented here show dynamics that could be interpreted as a single Q band to the decay of the SE and the excited state absorption (ESA) of the Soret band, and rise of the ESA
Summary
Corroles are a developing class of tetrapyrrole-based photosensitizers with relatively unexplored photophysical properties [1,2,3,4]. A combined study on the ultrafast electronic and tracking the photoreaction of corroles [35,39,40,41,42,43,44,45,46]. A combined study on the ultrafast electronic and vibrational dynamics of a brominated corrole system demonstrated intersystem crossing to the triplet vibrational dynamics of a brominated corrole system demonstrated intersystem crossing to the triplet manifold with a time constant of 100 ps and a quantum yield of close to one [39]. Leading to changes in the electronic structure of the complex, is not fully understood It is unclear if the absorption spectra of the triplet and singlet excited states are similar for most. It has been reported that excitation for most corroles or if the spectra are sensitive to metal ions and ligands. Short wavelengthpart partof ofthe the absorption absorption spectrum scaled-down by by a factor of 3.of 3
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