1. Single-File Diffusion in Crystalline Molecular Wheel Nanotubes
Clifford R. Bowers, Chemistry Department, University of Florida, Gainesville
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Hyperpolarized xenon-129 NMR was applied to crystalline Ga10 and Ga18 molecular wheels. Chemical shift and line width studies revealed information about the translational dynamics and guest-host interactions. Diffusion of xenon atoms in the two types of molecular wheel crystals was probed by hyperpolarized selective saturation-recovery NMR (shown right). A transition from single-file diffusion to Fickian diffusion was expected based on the channel sizes.
Selective saturation-recovery results in Ga10 wheel crystals. Dashed lines: one-parameter fits to the single-file diffusion model. Solid line: Fickian diffusion model does not fit the data [J. Am. Chem. Soc., 2010, 132, 5387–5393]