(39e) Dynamic Covalent Assembly of Abiotic, Information-Bearing Oligomers

Self-assembly processes are often based upon weak intermolecular interactions, one consequence of which is that the assembled structures are often fragile and susceptible to thermal or mechanical degradation. Covalent bonds typically exhibit bond energies that are over an order of magnitude higher than those for hydrogen bonds and could conceivably provide a route for the fabrication of far more robust assemblies; however, the selective creation of exquisite nanostructures by self-assembly and the toughness imparted by covalent bonds are generally perceived as mutually exclusive owing to the prevalent irreversibility of covalent bond-generating reactions. Fortunately, several covalent interactions are known to be reversible under particular reaction conditions, enabling the error correction mechanism that is essential for the selective fabrication of supramolecular structures. As a result of the enormously greater strength and directionality offered by covalent bonds in comparison to weak intermolecular interactions, these 'dynamic' covalent chemistries offer an elegant approach to nanostructure assembly that combines complexity AND toughness. Here, we will describe the synthesis and self-assembly of sequence specific oligomers mediated by dynamic covalent interactions, including the dynamic covalent assembly of molecular ladders with up to sixteen rungs between complementary peptoid oligomers bearing either amine, aldehyde, boronic acid, or catechol functional groups, the concurrent assembly of greater than two oligomeric precursor strands to yield long molecular ladders and wide molecular grids, and the in situ deprotection and subsequent, information-directed assembly of strands bearing both amine and aldehyde functional groups.