Petersen, Anne Ugleholdt, Jevric, Martyn, Mandle, Richard J orcid.org/0000-0001-9816-9661 et al. (5 more authors) (2017) Photoswitching of Dihydroazulene Derivatives in Liquid-Crystalline Host Systems. Chemistry : A European Journal. pp. 5090-5103. ISSN 1521-3765
Abstract
Photoswitches and dyes in the liquid-crystalline nematic phase have the potential for use in a wide range of applications. A large order parameter is desirable to maximize the change in properties induced by an external stimulus. A set of photochromic and nonphotochromic dyes were investigated for these applications. It was found that a bent-shaped 7-substituted dihydroazulene (DHA) photoswitch exhibited liquid-crystalline properties. Further investigation demonstrated that this material actually followed two distinct reaction pathways on heating, to a deactivated form by a 1,5-sigmatropic shift and to a linear 6-substituted DHA. In addition, elimination of hydrogen cyanide from the photoactive DHA gave both bent and linear azulene dyes. In a nematic host that has no absorbance around 350 nm, it was found that only the linear DHA derivative has nematic properties; however, both 6- and 7-substituted DHAs were found to have large order parameters. In the nematic host, ring opening of either DHA to the corresponding vinylheptafulvene resulted in a decrease in dichroic order parameter and an unusually fast back-reaction to a mixture of both DHAs. Likewise, only the linear azulene derivative showed mesomorphic properties. In the same nematic host, large order parameters were also observed for these dyes.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. |
Keywords: | Journal Article |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Chemistry (York) |
Funding Information: | Funder Grant number EPSRC EP/M020584/1 |
Depositing User: | Pure (York) |
Date Deposited: | 31 Mar 2017 16:20 |
Last Modified: | 01 Dec 2024 01:09 |
Published Version: | https://doi.org/10.1002/chem.201700055 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1002/chem.201700055 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:114423 |