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Abstract Water‐mediated proton conductivity in nanoporous materials is influenced by channel water ordering and the hydrophobicity/hydrophilicity of interior walls, making metal‐organic nanotubes (MONTs) useful systems for exploring these relationships due to their high crystallinity and tunable hydrophobicity. In the current study, electrochemical impedance spectroscopy is utilized to explore the proton conductivity on two metal organic nanotubes (UMONT and Cu‐LaMONT) with weak hydrophobic behavior that possess extended water networks within the 1‐D channels. Measurements performed at 95% RH and 20 °C indicate values of 1.63 × 10−4S cm−1for UMONT and 3.80 × 10−4S cm−1for Cu‐LaMONT, which is lower than values for walls with acidic, hydrophilic functional groups or nanotubular materials with strictly hydrophobic behavior. Proton conductivity decreases sharply with lower humidity, with Cu‐LaMONT being more sensitive to humidity changes. At low temperatures, UMONT outperforms LaMONT due to its well‐established hydrogen bonding network and hydrophobic interior. The anisotropic nature of proton conduction is also confirmed through pelletized powder sample analysis, emphasizing that the conductivity occurs through the water networks located within the 1‐D MONT channels. These findings emphasize the importance of understanding water–pore interactions and the resulting proton conductivity mechanisms to understand complex systems and design advanced materials.
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This content will become publicly available on November 21, 2025
Water Networks within Metal Organic Nanotubes: Assessment of Techniques to Understand Structure and Properties.
Abstract Hybrid materials, such as metal organic nanotubes (MONTs) can possess nanoconfined water molecules within their pore space and the overall behavior of the water within the material may be tuned based upon interactions with the inner channel walls. We have previously developed a range of methods (electron density mapping, kinetic models, and water interaction enthalpies) to evaluate water behavior under nanoconfinement using a uranium‐based metal organic nanotube (UMONT) but have not explored their applicability across a range of materials. In the current study, we test our methodologies on two additional MONT materials (LaMONTandCu‐LaMONT) to determine if the techniques can be utilized in other systems to predict behavior within complex hybrid materials. In addition, we explored how to use Hirshfeld surface maps generated by the CrystalExplorer software in the visualization and prediction of water behavior within complex hybrid materials.
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- Award ID(s):
- 2004220
- PAR ID:
- 10585624
- Publisher / Repository:
- European Chemical Societies Publishing
- Date Published:
- Journal Name:
- European Journal of Inorganic Chemistry
- Volume:
- 27
- Issue:
- 33
- ISSN:
- 1434-1948
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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