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Shape-switchable azo-macrocycles

Mueri, Marcel and Schuermann, Klaus C. and De Cola, Luisa and Mayor, Marcel. (2009) Shape-switchable azo-macrocycles. European Journal of Organic Chemistry, 2009 (15). pp. 2562-2575.

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Official URL: http://edoc.unibas.ch/dok/A5259896

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Abstract

The synthesis of four shape-switchable macrocycles comprising different peripheral substituents is described. The macrocycles 1-4 consist of m-terphenyl semicircles interlinked by two azo joints, These macrocycles were assembled from nitro-functionahzed m-terphenyl moieties through reductive dimerization. The semicircles were assembled through Suzuki cross-coupling reactions. The molecular weights of the macrocycles were determined by vapour pressure osmometry, because mass spectrometry failed in the cases of 2 and 3. The E -< Z photoisomerization reactions were analysed by UV/Vis spectroscopy complemented by H-1 NMR studies. A very slow thermal back-reaction indicated considerable stabilization of the Z isomer. The reduced efficiency of the thermal back-reaction probably arises from the reduced degree of freedom due to the mechanical interlinking of the two azo groups. The photostationary state consisted of all-Z (85 %) and all-E isomers (15 %). The E -< Z transformation induced by irradiation displayed simple exponential kinetics, which indicates pairwise switching of the two azo groups in a macrocycle, at least on the timescale under investigation. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Faculties and Departments:05 Faculty of Science > Departement Chemie > Chemie > Molecular Devices and Materials (Mayor)
UniBasel Contributors:Mayor, Marcel
Item Type:Article, refereed
Article Subtype:Research Article
Publisher:Wiley
ISSN:1434-193X
e-ISSN:1099-0690
Note:Publication type according to Uni Basel Research Database: Journal article
Identification Number:
Last Modified:05 Apr 2017 14:10
Deposited On:22 Mar 2012 14:06

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