Dithienylethene-based donor-π-acceptor photochromic dyes were synthesized to investigate the effect of the structure on photo-switching properties. Specifically, 3,5-dimethoxyphenyl and 4,4′-tert-butyltriphenylamino groups (donors) and benzoic and cyanoacetic acid groups (acceptors) were attached to an oxazole-based dithienylethene core in a horizontal or vertical fashion. The photochromic properties of these dyes were probed by UV–visible absorption spectroscopy upon exposure to UV (365 nm) and visible (>400 nm) light. The dye bearing 3,5-dimethoxyphenyl and carboxylic acid groups showed the best photochromic behavior in terms of quantum yield, and response time, which confirmed that strong electron-withdrawing substituents can hinder photo-induced cyclization by decreasing electron density at thiophene ring carbons 2 and 2’. Moreover, the introduction of an electron-withdrawing group onto the cycloethene moiety of vertical-type dyes led to a lower photochromic quantum yield than the introduction of an electron-withdrawing group at thiophene ring positions 5 and 5’.
Bibliographical noteFunding Information:
This work was supported by the Mid-Career Researcher Program ( 2017R1A2A1A17069537 ) funded by the National Research Foundation of Republic of Korea, the Technology Innovation Program (No. 10052798 ) funded by the Ministry of Trade, Industry and Energy, Republic of Korea, and the Postdoc Researcher Supporting Program (Project No. 2019-12-0021 ) funded by Yonsei University.
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All Science Journal Classification (ASJC) codes
- Chemical Engineering(all)
- Process Chemistry and Technology