Solid-state NMR is an extremely powerful method for probing molecular-level dynamics. Our group is particular interested in the study of such motions in metal-organic framework materials. Dynamic molecules can be arranged in an ordered manner by incorporating them into the skeleton of metal-organic frameworks (MOFs). These molecules can then undergo coherent motion, leading to potential applications as sensors and molecular switches and machines. While single-crystal X-ray diffraction can be used to determine the structure of the framework, it provides little information on the dynamic components.

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Our group uses variable temperature 2H SSNMR to study the rotational motions of the "wheels" (crown ethers) in these systems providing insight into the modes (i.e., jumping, partial or full rotation) and rates of these dynamic processes. Using these techniques, we are able to determine which factors (i.e., ring size, guest molecules, temperature, etc.) affect the motions of the dynamic components. This information will lead to the rational design of systems with finely tuned motions.

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Variable-temperature 2H SSNMR can also be used to study the motions of the linker molecules, revealing motional behaviour that changes with different molecular architectures, guest molecules, and crown ether sizes.

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We can also use variable temperature 1H-13C CP/MAS NMR experiments to observe a variety of different motional modes, including molecular shuttling (i.e., motion of the crown ether wheel down the "strut").

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Selected papers on MOFs


  1. Gonzalez-Nelson, A.; Mula, S.; Šimėnas, M.; Balčiu̅nas, S.; Altenhof, A. R.; Vojvodin, C. S.; Canossa, S.; Banys, J.; Schurko, R. W.; Coudert, F.-X.; van der Veen, M. A. Emergence of Coupled Rotor Dynamics in Metal–Organic Frameworks via Tuned Steric Interactions. J. Am. Chem. Soc. 2021, 143, 12053–12062. https://doi.org/10.1021/jacs.1c03630.
  2. Gholami, G.; Wilson, B. H.; Zhu, K.; O’Keefe, C. A.; Schurko, R. W.; Loeb, S. J. Exploring the Dynamics of Zr-Based Metal–Organic Frameworks Containing Mechanically Interlocked Molecular Shuttles. Faraday Discuss. 2021, 225, 358–370. https://doi.org/10.1039/D0FD00004C.
  3. Stirk, A. J.; Wilson, B. H.; O’Keefe, C. A.; Amarne, H.; Zhu, K.; Schurko, R. W.; Loeb, S. J. Applying Reticular Synthesis to the Design of Cu-Based MOFs with Mechanically Interlocked Linkers. Nano Res. 2021, 14, 417–422. https://doi.org/10.1007/s12274-020-3123-z.
  4. O’Keefe, C. A.; Mottillo, C.; Vainauskas, J.; Fábián, L.; Friščić, T.; Schurko, R. W. NMR-Enhanced Crystallography Aids Open Metal-Organic Framework Discovery Using Solvent-Free Accelerated Aging. Chem. Mater. 2020, 32, 4273–4281. https://doi.org/10.1021/acs.chemmater.0c00894.
  5. Martinez-Bulit, P.; O’Keefe, C. A.; Zhu, K.; Schurko, R. W.; Loeb, S. J. Solvent and Steric Influences on Rotational Dynamics in Porphyrinic Metal-Organic Frameworks with Mechanically Interlocked Pillars. Cryst. Growth Des. 2019, 19, 5679–5685. https://doi.org/10.1021/acs.cgd.9b00669.
  6. Farahani, N.; Zhu, K.; O’Keefe, C. A.; Schurko, R. W.; Loeb, S. J. Thermally Driven Dynamics of a Rotaxane Wheel about an Imidazolium Axle inside a Metal–Organic Framework. Chempluschem 2016, 81, 836–841. https://doi.org/10.1002/cplu.201600176.
  7. Vukotic, V. N.; O’Keefe, C. A.; Zhu, K.; Harris, K. J.; To, C.; Schurko, R. W.; Loeb, S. J.; Nicholas Vukotic, V.; O’Keefe, C. A.; Zhu, K.; Harris, K. J.; To, C.; Schurko, R. W.; Loeb, S. J. Mechanically Interlocked Linkers inside Metal-Organic Frameworks: Effect of Ring Size on Rotational Dynamics. J. Am. Chem. Soc. 2015, 137, 9643–9651. https://doi.org/10.1021/jacs.5b04674.
  8. Zhu, K.; O’Keefe, C. A.; Vukotic, V. N.; Schurko, R. W.; Loeb, S. J. A Molecular Shuttle That Operates inside a Metal-Organic Framework. Nat. Chem. 2015, 7, 514–519. https://doi.org/10.1038/NCHEM.2258.
  9. Zhu, K.; Vukotic, V. N.; Okeefe, C. A.; Schurko, R. W.; Loeb, S. J. Metal-Organic Frameworks with Mechanically Interlocked Pillars: Controlling Ring Dynamics in the Solid-State via a Reversible Phase Change. J. Am. Chem. Soc. 2014, 136, 7403–7409. https://doi.org/10.1021/ja502238a.
  10. Vukotic, V. N.; Harris, K. J.; Zhu, K.; Schurko, R. W.; Loeb, S. J. Metal-Organic Frameworks with Dynamic Interlocked Components. Nat. Chem. 2012, 4, 456–460. https://doi.org/10.1038/nchem.1354.

Selected papers on molecular-level dynamics


  1. Vukotic, V. N.; O’Keefe, C. A.; Zhu, K.; Harris, K. J.; To, C.; Schurko, R. W.; Loeb, S. J.; Nicholas Vukotic, V.; O’Keefe, C. A.; Zhu, K.; Harris, K. J.; To, C.; Schurko, R. W.; Loeb, S. J. Mechanically Interlocked Linkers inside Metal-Organic Frameworks: Effect of Ring Size on Rotational Dynamics. J. Am. Chem. Soc. 2015, 137, 9643–9651. https://doi.org/10.1021/jacs.5b04674.
  2. Prack, E.; O’Keefe, C. A.; Moore, J. K.; Lai, A.; Lough, A. J.; Macdonald, P. M.; Conradi, M. S.; Schurko, R. W.; Fekl, U. A Molecular Rotor Possessing an H-M-H ``Spoke{’’} on a P-M-P ``Axle{’’}: A Platinum(II) Trans-Dihydride Spins Rapidly Even at 75 K. J. Am. Chem. Soc. 2015, 137, 13464–13467. https://doi.org/10.1021/jacs.5b08213.
  3. Schurko, R. W.; Wi, S.; Frydman, L. Dynamic Effects on the Powder Line Shapes of Half-Integer Quadrupolar Nuclei: A Solid-State NMR Study of XO4- Groups. J. Phys. Chem. A 2002, 106, 51–62. https://doi.org/10.1021/jp0130214.