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  • Review Article
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Metal–organic cages for molecular separations

Nature Reviews Chemistry volume 5, pages 168–182 (2021)Cite this article

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Abstract

Separation technology is central to industries as diverse as petroleum, pharmaceuticals, mining and life sciences. Metal–organic cages, a class of molecular containers formed via coordination-driven self-assembly, show great promise as separation agents. Precise control of the shape, size and functionalization of cage cavities enables them to selectively bind and distinguish a wide scope of physicochemically similar substances in solution. Extensive research has, thus, been performed involving separations of high-value targets using coordination cages, ranging from gases and liquids to compounds dissolved in solution. Enantiopure capsules also show great potential for the separation of chiral molecules. The use of crystalline cages as absorbents, or the incorporation of cages into polymer membranes, could increase the selectivity and efficiency of separation processes. This Review covers recent progress in using metal–organic cages to achieve separations, with discussion of the many methods of using them in this context. Challenges and potential future developments are also discussed.

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Fig. 1: Metal–organic cages used for cargo extraction in solution.
Fig. 2: Phase transfer of metal–organic cages for target separation.
Fig. 3: Metal–organic cages for guest separation through crystallization or precipitation.
Fig. 4: Crystalline metal–organic cages as absorbents for target separation.
Fig. 5: Crystalline metal–organic cages for fullerene separation.
Fig. 6: Amorphous metal–organic cages as absorbents for guest separation.
Fig. 7: Metal–organic-cage-incorporated polymer membranes for target separation.
Fig. 8: Metal–organic-cage-decorated capillary electrochromatography column for target separation.

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Acknowledgements

This work was supported by the European Research Council (695009) and the UK Engineering and Physical Sciences Research Council (EPSRC EP/P027067/1). D.Z. acknowledges a Herchel Smith Research Fellowship from the University of Cambridge.

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Authors and Affiliations

  1. Department of Chemistry, University of Cambridge, Cambridge, UK

    Dawei Zhang, Tanya K. Ronson, You-Quan Zou & Jonathan R. Nitschke

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  1. Dawei Zhang
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  2. Tanya K. Ronson
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  3. You-Quan Zou
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  4. Jonathan R. Nitschke
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Contributions

D.Z. and T.K.R. researched the literature for the Review. D.Z. wrote the first version of the manuscript. T.K.R., Y.-Q.Z. and D.Z. prepared the figures. All authors contributed to the discussion and editing of the manuscript before submission.

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Correspondence to Jonathan R. Nitschke.

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Zhang, D., Ronson, T.K., Zou, YQ. et al. Metal–organic cages for molecular separations. Nat Rev Chem 5, 168–182 (2021). https://doi.org/10.1038/s41570-020-00246-1

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