Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 27: Photoswitchable Materials

CPP 27.6: Talk

Tuesday, March 21, 2017, 15:15–15:30, ZEU 114

Switching Thin Films of Metal-Organic Frameworks with Visible Light — •Kai Müller and Lars Heinke — Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany

Stimuli responsive molecules, also referred to as smart molecules, change their properties when exposed to external signals like 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 photoswitchable smart materials. Here, 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 can be reversibly switched between the trans and cis state by green and violet light, avoiding UV light. It is demonstrated that the uptake of guest molecules by these MOF films can be significantly increased in a fully remote controlled way. Furthermore, membrane separation experiments demonstrate the switching of the molecular separation factor by illumination with light of different color. The light-induced changes of the size of the pore windows result in the switching of the selection factor.