Information in nucleic acids is encoded in their nucleobase residue sequences. The double and triple hydrogen bonding between paired nucleobase residues of adenine–thymine and guanine–cytosine, respectively, enable complementary nucleic acid sequences to selectively self-assemble, yielding molecular ladders encoded in base-4. Owing to this sequence-selective self-assembly, nucleic acids have emerged as versatile nanoconstruction media where, upon thermal melting and annealing, mixtures of designed nucleic acid strands can hybridize to afford complex, multi-dimensional structures. Unfortunately, the versatility of nucleic acid assemblies is tempered by their thermal and mechanical instability, attributable to the weakness of the hydrogen bonds that hold the strands together. The substitution of the canonical nucleic acid base pairs with dynamic covalent base pairs would preclude this instability and yield a unique and powerful nanofabrication strategy wherein the complex, information-driven assembly of nucleic acids is combined with the strength of covalent bonds.<br/><br/>Mimicking the sequence-selective hybridization of nucleic acids in robust, abiotic systems, the self-assembly of molecular ladders incorporating covalent bond rungs from complementary oligomeric precursor strands bearing covalently coreactive pendant groups has been previously described; nevertheless, the systems examined to date have typically employed a single reactant pair such that residue sequences can only be encoded in binary. In contrast, mimicking the base-4 encoding of nucleic acids requires the use of dual concurrent and orthogonal dynamic covalent reactant pairs. We demonstrate an abiotic, DNA mimetic dynamic covalent system encoded in base-4 by demonstrating the sequence-directed self-assembly of molecular ladders and grids from oligomers bearing two covalently coreactive pendant group pairs whose condensation reactions are orthogonal but proceed under the same reaction conditions.

Dynamic covalent assembly of information-bearing, base-4-encoded oligomers

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.