Photoisomerization of Arylazopyrazole Photoswitches: Stereospecific Excited‐State Relaxation |
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| Authors: | Dr Ya‐Ting Wang Dr Xiang‐Yang Liu Prof?Dr Ganglong Cui Prof?Dr Wei‐Hai Fang Prof?Dr Walter Thiel |
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| Institution: | 1. Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, China;2. Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr, Germany |
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| Abstract: | Electronic structure calculations and nonadiabatic dynamics simulations (more than 2000 trajectories) are used to explore the Z–E photoisomerization mechanism and excited‐state decay dynamics of two arylazopyrazole photoswitches. Two chiral S1/S0 conical intersections with associated enantiomeric S1 relaxation paths that are barrierless and efficient (timescale of ca. 50 fs) were found. For the parent arylazopyrazole (Z8) both paths contribute evenly to the S1 excited‐state decay, whereas for the dimethyl derivative (Z11) each of the two chiral cis minima decays almost exclusively through one specific enantiomeric S1 relaxation path. To our knowledge, the Z11 arylazopyrazole is thus the first example for nearly stereospecific unidirectional excited‐state relaxation. |
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| Keywords: | arylazopyrazoles conical intersections nonadiabatic dynamics photoisomerization photoswitches |
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