Enhancement of coloring under ultraviolet irradiation in photochromic diarylbenzenes

• Published in: Tetrahedron letters Vol. 61; no. 24; p. 151968
• Main Authors: Hamatani, Shota, Kitagawa, Daichi, Nakahama, Tatsumoto, Kobatake, Seiya
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 11.06.2020
• Subjects: bleaching; chemical reactions; Diarylbenzene; Enhancement of coloring; irradiation; isomers; moieties; oxazoles; Photochromism; spectral analysis; Substitution of aryl groups; T-type photoswitch; thiazoles; thiophene; ultraviolet radiation; Photochromism; Diarylbenzene; T-type photoswitch; Substitution of aryl groups; Enhancement of coloring
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2020.151968

[Display omitted] •Novel T-type photochromic diarylbenzenes were designed and synthesized.•The aryl moiety was changed from thiophene ring to thiazole and oxazole rings.•The thermal bleaching reaction rate was decelerated.•The absorption band of the closed-ring isomer was blue-shifted.•The coloring under ultraviolet light irradiation was significantly improved. 1,2-Diarylbenzenes have been developed as a new family of T-type photochromic switches that have potential applications such as ophthalmic lenses, real-time holography, and super-resolution microscopy. In this work, we have designed and synthesized novel diarylbenzenes bearing thiazole and oxazole rings as the aryl groups to improve the coloring under ultraviolet (UV) irradiation. The substitution of the aryl groups with thiazole and oxazole rings having lower aromaticity than thiophene brought about the deceleration of the thermal bleaching reaction, the blue-shift of the absorption spectra of the closed-ring isomers, and the increase of the photocyclization reactivity, which results in the enhancement of the coloring when exposed to UV light. The results would provide useful information for the development of practical applications using diarylbenzene chromophores.