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The title compound, C 10 H 13 NO 2 S, was synthesized by a nucleophilic substitution reaction between allyl amine and p -toluenesulfonyl chloride. The sulfonate S—O bond lengths are 1.4282 (17) and 1.4353 (17) Å, and the C—N—S—C torsion angle involving the sulfonamide moiety is −61.0 (2)°. In the crystal, centrosymmetric dimers of the title compound are present via intermolecular N—H...O hydrogen bonds between sulfonamide groups. These dimers are linked into ribbons along the c -axis direction through offset π–π interactions.
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Hydronium ion diffusion in model proton exchange membranes at low hydration: insights from ab initio molecular dynamics
Fuel-cell deployable proton exchange membranes (PEMs) are considered to be a promising technology for clean and efficient power generation. However, a fundamental atomistic understanding of the hydronium diffusion process in the PEM environment is an ongoing challenge. In this work, we employ fully atomistic ab initio molecular dynamics to simulate diffusion mechanisms of the hydronium ion in a model PEM. In order to mimic a precise polymer with a layered morphology, as recently introduced by Trigg, et al. , Nat. Mater. , 2018, 17 , 725, a nano-confined environment was created composed of graphane bilayers to which sulfonate end groups (SO 3 − ) are attached, and the space between the bilayers was subsequently filled with water and hydronium ions up to λ values of 3 and 4, where λ denotes the water-to-anion ratio. We find that for the low λ value, the water distribution is not homogeneous, which results in an incomplete second solvation shell for H 3 O + , fewer water molecules in the vicinity of SO 3 − , and a higher probability of obtaining a coordination number of ∼1 for the nearest oxygen neighbor to SO 3 − . These conditions increase the probability that H 3 O + will react with SO 3 − according to the reaction SO 3 − + H 3 O + ↔ SO 3 H + H 2 O, which was found to be an essential part of the hydronium diffusion mechanism. This suggests there are optimal hydration conditions that allow the sulfonate end groups to take an active part in the hydronium diffusion mechanism, resulting in high hydronium conductivity. We expect that the results of this study could help guide synthesis and experimental characterization used to design new PEM materials with high hydronium conductivity.
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- Award ID(s):
- 1904767
- PAR ID:
- 10267608
- Date Published:
- Journal Name:
- Journal of Materials Chemistry A
- Volume:
- 9
- Issue:
- 4
- ISSN:
- 2050-7488
- Page Range / eLocation ID:
- 2448 to 2458
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1039/d0ta10565a
