Crystallization‐Induced Emission of Azobenzene Derivatives. (23rd August 2019)

• Record Type: Journal Article
• Authors: Yamauchi, Mitsuaki; Yokoyama, Kosuke; Aratani, Naoki; Yamada, Hiroko; Masuo, Sadahiro
• Is Part Of: Angewandte Chemie. Volume 131:Number 40(2019)
• Page Start: 14311
• Page End: 14316
• Publication Date: 2019-08-23
• Subjects: Azobenzol -- Kinetik -- Kristallisationsinduzierte Emission -- Selbstassemblierung; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201908121
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: Most azobenzene derivatives are utilized as well‐defined photoresponsive materials, but their emission properties have not been of great interest as they are relatively poor. Here, we report crystallization‐induced emission (CIE) based on the suppression of the photoisomerization of azobenzene derivatives. Although these molecules show negligible emission in solution, their microcrystals exhibit intense emission from the azobenzene moieties as a result of CIE. Upon rapid precipitation, fine particles with low crystallinity were kinetically formed and underwent CIE over time with a concomitant increase in crystallinity. Furthermore, we demonstrated "photocutting" of an emissive single crystal using a strong laser by a combination of CIE behavior and photomelting based on the photoisomerization of the azobenzene moiety. Our results regarding the CIE behavior of azobenzene derivatives in addition to their photoisomerization can provide a new platform for developing photoresponsive luminescent materials. Abstract : Leuchtendes Azobenzol : Die kristallisationsinduzierte Emission (CIE) eines Azobenzol‐Derivats wurde durch die Herstellung von Mikrokristallen demonstriert. Die Unterdrückung der Photoisomerisierung der Azobenzolgruppe stellt einen Schlüsselfaktor für den CIE‐Mechanismus dar, und die Erkenntnisse können für die Entwicklung neuartiger photolumineszierender Materialien genutzt werden.