A ring-shaped molecule now makes it possible to control the self-assembly of nanoparticles from the outside, according to an Amsterdam-based group writing in Nature Chemistry.

The synthesis of crown ethers, or the self-assembly of small nanoparticles, involves using templates such as anions or cations around which molecules form. ‘These are always at the centre’, says Joost Reek, Professor of Homogeneous and Supramolecular Catalysis at the University of Amsterdam. ‘If you look at this type of self-assembly process, you see a small guest [the template, ed.] around which a structure is built. This is called an endo-template.’ Reek and his team have now reversed this process by using exo-templates to influence self-assembly from the outside. ‘This is something completely new.’