Annual Review 2024-2025

A N N U A L R E V I E W 2 0 2 4 / 2 5 C RY S TA L L O G R A P H Y G R O U P 14 Hierarchical self-assembly: unlocking new functional materials Pushed and pulled by competing interactions, molecules can self-assemble into complex structures. Using supramolecular self-assembly, we can synthesise materials with unique structures and function. However, predicting how molecules will assemble themselves, and controlling the reaction conditions to nudge them into forming a desirable structure, is challenging. Using porous cage molecules as building blocks for larger structures is an attractive prospect. A team of researchers led by the University of Liverpool, Imperial College London and Heriot-Watt University has developed a hierarchical cage molecule that can adsorb other molecules, like carbon dioxide and sulphur hexafluoride. A key aspect of the project was using computer modelling to accurately predict how the precursor molecules would self-assemble into a new material. In order to validate the accuracy of the computer predictions, they performed diffraction experiments at I11 and I19. This hierarchical cage molecule has a high storage capacity for gas molecules like carbon dioxide and sulphur hexafluoride. In the future, complex hierarchical structures could be used to perform challenging molecular separation, such as filtering toxic volatile organic compounds (VOCs) from the air or have applications in medical science. DOI:10.1038/s44160-024-00531-7 A-C, The predicted structure (red) overlaid with the single-crystal X-ray diffraction structure (blue) is shown as viewed along the a (a), b (b) and c (c) crystallographic axes, highlighting the close structural similarity between the predicted and experimental structures. A B C