title: Switching Thin Films of Azobenzene-Containing Metal-Organic Frameworks with Visible Light.
abstract: Stimuli-responsive molecules change their properties when exposed to external signals, such as light, and enable the preparation of smart materials. UV light, which often destroys organic materials, is typically required for activating the desired response of photoswitchable compounds, significantly limiting the potential applications of light-operated smart materials. Herein, we present the first metal-organic framework (MOF), which enables reversible modulation of key properties upon irradiation with visible light only. The fluorinated azobenzene side groups in the MOF structure can be reversibly switched between the trans and cis state by green and violet light, avoiding UV light. It was demonstrated that the uptake of guest molecules by these MOF films can be switched in a fully remote-controlled way. The membrane separation of hydrogen/hydrocarbon mixtures was investigated. The light-induced changes of the MOF pore size result in the switching of the permeation and of the selection factor.
authors.affiliation: Chemistry of Oxydic and Organic Interfaces, Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Müller
authors.affiliation: Institute for Physical Chemistry and Electrochemistry, Leibniz University Hanover, Callinstrasse 3a, 30167, Hannover, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Knebel
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany.
authors.forename: Fangli
authors.initials: F
authors.lastname: Zhao
authors.affiliation: Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse 2, 12489, Berlin, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Bléger
authors.affiliation: Institute for Physical Chemistry and Electrochemistry, Leibniz University Hanover, Callinstrasse 3a, 30167, Hannover, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Caro
authors.affiliation: Chemistry of Oxydic and Organic Interfaces, Institute of Functional Interfaces, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany.
authors.forename: Lars
authors.identifier: http://orcid.org/0000-0002-1439-9695
authors.initials: L
authors.lastname: Heinke
keywords: membrane separation; metal-organic frameworks; photoswitching; remote control; thin films