A complex molecular knot with eight crossing points has been made

Molecular knot - cropped

Source: © Robert W. McGregor

David Leigh’s group at the University of Manchester, UK, has tied the tightest molecular knot to date, comprising three molecular strands plaited together to create a circular triple helix, a loop with eight crossings.

The knot was tied using existing self-assembly techniques to weave the ligand strands around four octahedral iron(II) ions which fix the eight crossing points. The strands are joined up to close the loop using a transition metal catalyst, and the ions can then be removed.

Leigh’s team has a long track record producing interlocking molecular structures, including a knot shaped like a Star of David and a trefoil knot that can act as a catalyst. This latest knot is the most complex regular woven molecule ever made.