Accompanying the continued progress towards atomic control over macromolecular, or supramolecular, structures and materials has arisen the challenge of architecting and engineering regular, but modifiable, self-assembled nanostructures. Conventional self-assembly mechanisms involve the use of inherently weak intermolecular bonds allowing for rearrangement and error-checking of sub-units but result in comprehensive structures readily susceptible to thermal and mechanical degradation. Attempts to incorporate robust bonds induce kinetic trapping of sub-units, and thus incomplete architectures and unselective hybridization between units. Here, we describe the dynamic covalent assembly of information-bearing peptoid oligomers, where information is encoded in their sequence of pendant groups, by employing scandium triflate as a multi-role reagent to deprotect ethylene acetal-protected aldehydes in situ, to affect the equilibrium of amine/aldehyde condensation reactions, and to catalyze imine rearrangement reactions. Thus, by initially utilizing high loadings of Sc(OTf)3 to deprotect and separate complementary strands, then reducing the Sc(III) concentration via extraction and annealing at raised temperature, the selective, information-directed assembly of these oligomers was achieved. Moreover, the precursor oligomers were differentiated by incorporating spacer residues of varying lengths, enabling characterization of the generated structures by mass spectrometry to affirm sequence-selective assembly.

Selective, information-directed dynamic covalent assembly of sequence-specific peptoids

256th National Meeting (2018)

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