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Atomic resolution of structural changes in elastic crystals of copper(II) acetylacetonate

Nature Chemistry volume 10, pages 6569 (2018) | Download Citation

Abstract

Single crystals are typically brittle, inelastic materials. Such mechanical responses limit their use in practical applications, particularly in flexible electronics and optical devices. Here we describe single crystals of a well-known coordination compound—copper(II) acetylacetonate—that are flexible enough to be reversibly tied into a knot. Mechanical measurements indicate that the crystals exhibit an elasticity similar to that of soft materials such as nylon, and thus display properties normally associated with both hard and soft matter. Using microfocused synchrotron radiation, we mapped the changes in crystal structure that occur on bending, and determined the mechanism that allows this flexibility with atomic precision. We show that, under strain, the molecules in the crystal reversibly rotate, and thus reorganize to allow the mechanical compression and expansion required for elasticity and still maintain the integrity of the crystal structure.

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Acknowledgements

We thank the Australian Research Council for support. Part of this research was undertaken on the MX1 and MX2 beamlines of the Australian Synchrotron, Clayton, Victoria, Australia. We thank Australian Synchrotron for travel support and their staff for assistance. We thank the University of Queensland, Queensland University of Technology and the Central Analytical Research Facility (CARF, QUT) for support.

Author information

Author notes

    • Anna Worthy
    •  & Arnaud Grosjean

    These authors contributed equally to this work.

Affiliations

  1. School of Chemistry, Physics and Mechanical Engineering, Faculty of Science and Engineering, Queensland University of Technology, GPO Box 2434, Brisbane, Queensland 4001, Australia

    • Anna Worthy
    • , Yanan Xu
    • , Cheng Yan
    •  & John C. McMurtrie
  2. School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia, Queensland 4072, Australia

    • Arnaud Grosjean
    • , Michael C. Pfrunder
    •  & Jack K. Clegg
  3. Australian Institute of Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland 4072, Australia

    • Grant Edwards

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Contributions

A.W., M.C.P. and A.G. synthesized the materials investigated. A.G., A.W., M.C.P., J.K.C. and J.C.M. performed the X-ray measurements. A.W., A.G., M.C.P., Y.X., C.Y. and G.E. performed the mechanical measurements. J.K.C. and J.C.M. conceptualized the studies and directed the research. A.W., A.G., M.C.P., J.K.C. and J.C.M. wrote the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Jack K. Clegg or John C. McMurtrie.

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Crystallographic information files

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    Supplementary information

    Crystallographic data for the unbent [Cu(acac)2]

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    Crystallographic data for Crystal 1 (structures a to p)

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    Supplementary information

    Crystallographic data for Crystal 2 (structures a to r)

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DOI

https://doi.org/10.1038/nchem.2848

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