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. 2021 Oct 22;60(48):25290–25295. doi: 10.1002/anie.202111748

Figure 2.

Figure 2

Spectroscopic and computational studies on the isomerization of PIO. (A) Comparison of the short timescale kinetic traces of the excited‐state absorption band of PIO dissolved in toluene and methanol, upon excitation at 500 nm. Inset: Evolution‐associated difference spectrum (EADS) obtained from global analysis of transient absorption data recorded for PIO in toluene upon excitation at 500 nm. (B) Representation of the full isomerization cycle in PIO. Surfaces obtained as a SF‐BH&HLYP/cc‐pVDZ single point calculation on the geometry optimized at the TD‐ωB97X‐D/MIDI! (S1) or GFN2‐xTB (S0) level of theory. Inset: Population of S0 and S1 states as a function of time obtained from OM2/MRCI NAMD calculations. (C) Differential spectra of E‐PIO in Et2O (3×10−4 M) upon irradiation with a 505 nm LED. PSS was reached after 22 min. Inset: kinetics observed at 443 nm when irradiating Z‐PIO with 420 nm LED vs. thermal isomerization.