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Making Fast Photoswitches Faster—Using Hammett Analysis to Understand the Limit of Donor–Acceptor Approaches for Faster Hemithioindigo Photoswitches
Author(s) -
Maerz Benjamin,
Wiedbrauk Sandra,
Oesterling Sven,
Samoylova Elena,
Nenov Artur,
Mayer Peter,
de VivieRiedle Regina,
Zinth Wolfgang,
Dube Henry
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201403661
Subject(s) - photoswitch , photoisomerization , chemistry , photochemistry , absorption (acoustics) , bistability , chemical physics , ultrafast laser spectroscopy , spectroscopy , materials science , isomerization , optoelectronics , optics , physics , quantum mechanics , catalysis , biochemistry
Hemithioindigo (HTI) photoswitches have a tremendous potential for biological and supramolecular applications due to their absorptions in the visible‐light region in conjunction with ultrafast photoisomerization and high thermal bistability. Rational tailoring of the photophysical properties for a specific application is the key to exploit the full potential of HTIs as photoswitching tools. Herein we use time‐resolved absorption spectroscopy and Hammett analysis to discover an unexpected principal limit to the photoisomerization rate for donor‐substituted HTIs. By using stationary absorption and fluorescence measurements in combination with theoretical investigations, we offer a detailed mechanistic explanation for the observed rate limit. An alternative way of approaching and possibly even exceeding the maximum rate by multiple donor substitution is demonstrated, which give access to the fastest HTI photoswitch reported to date.