title: Arylazoindazole Photoswitches: Facile Synthesis and Functionalization via SNAr Substitution.
abstract: A straightforward synthetic route to arylazoindazoles via nucleophilic aromatic substitution is presented. Upon deprotonation of the NH group, a C6F5-substituted formazan undergoes facile cyclization as a result of intermolecular nucleophilic substitution (SNAr). This new class of azo photoswitches containing an indazole five-membered heterocycle shows photochemical isomerization with high fatigue resistance. In addition, the Z-isomers have long thermal half-lives in the dark of up to several days at room temperature. The fluorinated indazole group offers a handle for further functionalization and tuning of its properties, as it is shown to be susceptible to a subsequent, highly selective nucleophilic displacement reaction.
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Raquel
authors.initials: R
authors.lastname: Travieso-Puente
authors.affiliation: Laboratoire CEISAM - UMR CNRS 6230, Université de Nantes , 2 Rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France.
authors.forename: Simon
authors.initials: S
authors.lastname: Budzak
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Peter
authors.initials: P
authors.lastname: Stacko
authors.affiliation: Organic Chemistry & Catalysis, Debye Institute for Nanomaterials Science, Utrecht University , Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
authors.forename: Johann T B H
authors.initials: JT
authors.lastname: Jastrzebski
authors.affiliation: Laboratoire CEISAM - UMR CNRS 6230, Université de Nantes , 2 Rue de la Houssinière, BP 92208, 44322 Nantes Cedex 3, France.|Institut Universitaire de France , 1, rue Descartes, 75005 Paris Cedex 5, France.
authors.forename: Denis
authors.identifier: 0000-0002-4217-0708
authors.initials: D
authors.lastname: Jacquemin
authors.affiliation: Stratingh Institute for Chemistry, University of Groningen , Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Edwin
authors.identifier: 0000-0002-5905-5108
authors.initials: E
authors.lastname: Otten