Encoding complexity within supramolecular analogues of frustrated magnets


The solid phases of gold(I) and/or silver(I) cyanides are supramolecular assemblies of inorganic polymer chains in which the key structural degrees of freedom—namely, the relative vertical shifts of neighbouring chains—are mathematically equivalent to the phase angles of rotating planar (‘XY’) spins. Here, we show how the supramolecular interactions between chains can be tuned to mimic different magnetic interactions. In this way, the structures of gold(I) and/or silver(I) cyanides reflect the phase behaviour of triangular XY magnets. Complex magnetic states predicted for this family of magnets—including collective spin-vortices of relevance to data storage applications—are realized in the structural chemistry of these cyanide polymers. Our results demonstrate how chemically simple inorganic materials can behave as structural analogues of otherwise inaccessible ‘toy’ spin models and also how the theoretical understanding of those models allows control over collective (‘emergent’) phenomena in supramolecular systems.

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Figure 1: Crystal structures of AuCN and AgCN and their relationship to the ground states of triangular XY (anti)ferromagnets.
Figure 2: Interactions in AuCN and AgCN.
Figure 3: Interactions and structural complexity in Au1/2Ag1/2(CN).


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A.B.C., M.J.C., J.A.M.P. and A.L.G. acknowledge financial support from the Engineering and Physical Sciences Research Council (EPSRC; EP/G004528/2), the Science and Technology Facilities Council (STFC) and the European Research Council (ERC; grant ref: 279705). High-pressure synchrotron X-ray powder diffraction measurements were carried out at the I15 Beamline, Diamond Light Source, UK. Quantum chemistry calculations made use of high performance computing resources from GENCI (grant x2015087069).

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A.B.C., M.J.C., J.A.M.P., F.-X.C. and A.L.G. conceived and designed the study. A.B.C., D.D. and M.G.T. performed the experiments. A.B.C., M.J.C., J.A.M.P. and A.L.G. interpreted the experimental data. F.-X.C. performed and interpreted the quantum chemistry calculations. A.L.G. wrote the paper. All authors discussed and commented on the manuscript.

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Correspondence to François-Xavier Coudert or Andrew L. Goodwin.

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Cairns, A., Cliffe, M., Paddison, J. et al. Encoding complexity within supramolecular analogues of frustrated magnets. Nature Chem 8, 442–447 (2016). https://doi.org/10.1038/nchem.2462

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