The self-sorting behavior of circular helicates and molecular knots and links

We report on multicomponent self-sorting to form open circular helicates of different sizes from a primary monoamine, FeII ions, and dialdehyde ligand strands that differ in length and structure by only two oxygen atoms. The corresponding closed circular helicates that are formed from a diamine - a molecular Solomon link and a pentafoil knot - also self-sort, but up to two of the Solomon-link-forming ligand strands can be accommodated within the pentafoil knot structure and are either incorporated or omitted depending on the stage that the components are mixed. It takes all sorts: Tris(bidentate) ligand strands that differ in length by just two atoms self-sort into circular helicates of different sizes with a monoamine and into different molecular topologies - a molecular Solomon link and a pentafoil knot - with a diamine (see picture). © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.