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Published on: July 19, 2019
Substituent effects in N-acetylated phenylazopyrazole photoswitches
Radek Tovtik1, Dennis Marzin1, Pia Weigel1
1Institute of Organic and Biomolecular Chemistry, Georg-August-University, Tammannstraße 2, 37077 Goettingen, Germany.
Abstract:
Phenylazopyrazole photoswitches proved to be valuable structural motifs for various applications ranging from materials science to medicine. Despite their potential, their structural diversity is still limited and a larger pool of substitution patterns remains to be systematically investigated. This is paramount as electronic effects play a crucial role in the behavior of photoswitches and a deeper understanding enables their straightforward development for specific applications. In this work, we synthesized novel N-acylpyrazole-based photoswitches and conducted a comparative study with 33 phenylazopyrazoles, comparing their photoswitching properties and the impact of electronic effects. Using UV-vis and NMR spectroscopy, we discovered that simple acylation of the pyrazole moiety leads to increased quantum yields of isomerization, long Z-isomer life-times, good spectral separation, and high photostability.
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