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  • Review Article
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Radical-pairing-induced molecular assembly and motion

Nature Reviews Chemistry volume 5, pages 447–465 (2021)Cite this article

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A Publisher Correction to this article was published on 18 June 2021

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Abstract

Radical-pairing interactions between conjugated organic π-radicals are relative newcomers to the inventory of molecular recognition motifs explored in supramolecular chemistry. The unique electronic, magnetic, optical and redox-responsive properties of the conjugated π-radicals render molecules designed with radical-pairing interactions useful for applications in various areas of chemistry and materials science. In particular, the ability to control formation of radical cationic or anionic species, by redox stimulation, provides a flexible trigger for directed assembly and controlled molecular motions, as well as a convenient means of inputting energy to fuel non-equilibrium processes. In this Review, we provide an overview of different examples of radical-pairing-based recognition processes and of their emerging use in (1) supramolecular assembly, (2) templation of mechanically interlocked molecules, (3) stimuli-controlled molecular switches and, by incorporation of kinetic asymmetry in the design, (4) the creation of unidirectional molecular transporters based on pumping cassettes powered by fuelled switching of radical-pairing interactions. We conclude the discussion with an outlook on future directions for the field.

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Fig. 1: Radical-recognition pairs.
Fig. 2: Radical-pairing-interactions-driven supramolecular assembly.
Fig. 3: Radical-pairing-interactions-templated assembly of mechanically interlocked molecules.
Fig. 4: Redox-controlled molecular switches driven by radical-pairing interactions.
Fig. 5: Radical-pairing-interactions-driven switchable molecular motions within mechanically interlocked molecules.
Fig. 6: Timeline for the advances in the design and synthesis of molecular pumps.
Fig. 7: Working mechanisms of different generations of the molecular pumps.
Fig. 8: Two examples of utilizing molecular pumps in the syntheses of mechanically interlocked polymers.

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Acknowledgements

The authors thank Northwestern University for its continuing financial support.

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Author notes

  1. These authors contributed equally: Kang Cai, Long Zhang.

Authors and Affiliations

  1. Department of Chemistry, Nankai University, Tianjin, China

    Kang Cai

  2. Department of Chemistry, Northwestern University, Evanston, IL, USA

    Long Zhang & J. Fraser Stoddart

  3. Department of Physics, University of Maine, Orono, ME, USA

    R. Dean Astumian

  4. School of Chemistry, University of New South Wales, Sydney, NSW, Australia

    J. Fraser Stoddart

  5. Stoddart Institute of Molecular Science, Department of Chemistry, Zhejiang University, Hangzhou, China

    J. Fraser Stoddart

  6. ZJU-Hangzhou Global Scientific and Technological Innovation Center, Hangzhou, China

    J. Fraser Stoddart

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  1. Kang Cai
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  2. Long Zhang
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  4. J. Fraser Stoddart
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K.C. and L.Z. contributed equally to this manuscript. All authors contributed to every aspect of the manuscript.

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Correspondence to Kang Cai, R. Dean Astumian or J. Fraser Stoddart.

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Cai, K., Zhang, L., Astumian, R.D. et al. Radical-pairing-induced molecular assembly and motion. Nat Rev Chem 5, 447–465 (2021). https://doi.org/10.1038/s41570-021-00283-4

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