Chemists have tied the knot! Researchers at the University of Jyväskylä, Finland, and the University of Edinburgh, UK, have constructed the most complicated chemical knot yet without resorting to biological materials, such DNA, to do so. The molecular knot ties itself through the self-assembly of five bis-aldehyde and five bis-amine building blocks, five metal cations and a chloride anion. The result is a 160-atom-loop with a pentafoil knot structure; it has five crossing points.

Not only are such demonstrations impressive, but creating such a structure could lead to even more complex supramolecular entities with new and untested physical properties.

• A synthetic molecular pentafoil knot
  J.-F. Ayme, J. E. Beves, D. A. Leigh, R. T. McBurney, K. Rissanen, D. Schultz,
  Nature Chem. 2011.
  DOI: 10.1038/nchem.1193