Water‐Mediated Proton Conduction in a Robust Triazolyl Phosphonate Metal–Organic Framework with Hydrophilic Nanochannels |
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Authors: | Salma Begum Zhaoyang Wang Dr Anna Donnadio Prof?Dr Ferdinando Costantino Prof?Dr Mario Casciola Dr Rustem Valiullin Dr Christian Chmelik Dr Marko Bertmer Prof?Dr Jörg Kärger Prof?Dr Jürgen Haase Prof?Dr Harald Krautscheid |
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Institution: | 1. Fakult?t für Chemie und Mineralogie, Universit?t Leipzig, Johannisallee 29, 04103 Leipzig (Germany);2. Department of Chemistry, University of Perugia, Via Elce di Sotto n.8, Perugia (Italy);3. Fakult?t für Physik und Geowissenschaften, Universit?t Leipzig, Linnéstrasse 5, 04103 Leipzig (Germany) |
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Abstract: | The development of water‐mediated proton‐conducting materials operating above 100 °C remains challenging because the extended structures of existing materials usually deteriorate at high temperatures. A new triazolyl phosphonate metal–organic framework (MOF) La3 L 4(H2O)6]Cl ? x H2O ( 1 , L 2?=4‐(4H‐1,2,4‐triazol‐4‐yl)phenyl phosphonate) with highly hydrophilic 1D channels was synthesized hydrothermally. Compound 1 is an example of a phosphonate MOF with large regular pores with 1.9 nm in diameter. It forms a water‐stable, porous structure that can be reversibly hydrated and dehydrated. The proton‐conducting properties of 1 were investigated by impedance spectroscopy. Magic‐angle spinning (MAS) and pulse field gradient (PFG) NMR spectroscopies confirm the dynamic nature of the incorporated water molecules. The diffusivities, determined by PFG NMR and IR microscopy, were found to be close to that of liquid water. This porous framework accomplishes the challenges of water stability and proton conduction even at 110 °C. The conductivity in 1 is proposed to occur by the vehicle mechanism. |
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Keywords: | diffusion studies impedance spectroscopy metal– organic frameworks microporous materials proton conduction |
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