Nature creates hierarchical, self-assembling structures across all length scales to achieve superior properties, for example, in mechanics, photonics, reactivity and adaptability. These hierarchical structures are well defined in both form and function, although generally only a limited number of building blocks are used. In natural systems, chirality, precise sequencing of macromolecules, and combinations of non-covalent interactions are known to play a central role in the formation of hierarchical structures and superstructures, suggesting that synergies between different structure-defining elements are crucial. In this perspective, we highlight selected examples from nature and present artificial examples exemplifying a transition from supramolecular polymers to structures with higher levels of aggregation. These include supramolecular systems based on chiral building blocks, which typically allow for hierarchical structures with tailored shapes and tuned helicity but also defined lateral dimensions. We also outline artificial supramolecular systems combining orthogonal secondary interactions, which allow the hierarchical structure to be confined to defined dimensions and shapes. Finally, we briefly discuss selected applications related to the hierarchy in the bulk or the corresponding surface of hierarchically structured systems. We also propose guidelines for defined hierarchical structures with potential to enhance light harvesting or to create artificial supramolecular antibodies.
Kreger et al. (Wed,) studied this question.