A Periodic System of Supramolecular Elements.

Chemistry "beyond the molecule" is based on weak, noncovalent, and reversible interactions. As a consequence of these bonds being weak, structural organization by folding and self-assembly can only be fully exploited with larger molecules that can provide multiple binding sites. Such "supramolecules" can now be synthesized and their folding into desired conformations predicted. A new level of chemistry can now be realized through the creation of non-natural entities composed of molecular building blocks with defined secondary structures. Herein we define these building blocks as "supramolecular elements". We anticipate that further research on such large molecules will reveal construction principles dictated by recurring motifs that govern structure formation through folding and self-assembly. These principles are comparable to the organization of atoms in the Periodic Table of Chemical Elements and may lead to the establishment of a Periodic System of Supramolecular Elements.