Sequence-Selective Formation of Synthetic H-Bonded Duplexes
Journal of the American Chemical Society
American Chemical Society
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Stross, A., Iadevaia, G., Nunez-Villanueva, D., & Hunter, C. (2017). Sequence-Selective Formation of Synthetic H-Bonded Duplexes. Journal of the American Chemical Society, 139 (36), 12655-12663. https://doi.org/10.1021/jacs.7b06619
Oligomers equipped with a sequence of phenol and pyridine N-oxide groups form duplexes via H-bonding interactions between these recognition units. Reductive amination chemistry was used to synthesize all possible 3-mer sequences: AAA, AAD, ADA, DAA, ADD, DAD, DDA, and DDD. Pairwise interactions between the oligomers were investigated using NMR titration and dilution experiments in toluene. The measured association constants vary by 3 orders of magnitude (102 to 105 M–1). Antiparallel sequence-complementary oligomers generally form more stable complexes than mismatched duplexes. Mismatched duplexes that have an excess of H-bond donors are stabilized by the interaction of two phenol donors with one pyridine N-oxide acceptor. Oligomers that have a H-bond donor and acceptor on the ends of the chain can fold to form intramolecular H-bonds in the free state. The 1,3-folding equilibrium competes with duplex formation and lowers the stability of duplexes involving these sequences. As a result, some of the mismatch duplexes are more stable than some of the sequence-complementary duplexes. However, the most stable mismatch duplexes contain DDD and compete with the most stable sequence-complementary duplex, AAA·DDD, so in mixtures that contain all eight sequences, sequence-complementary duplexes dominate. Even higher fidelity sequence selectivity can be achieved if alternating donor–acceptor sequences are avoided.
We thank the Engineering and Physical Sciences Research Council (EP/J008044/2) and European Research Council (ERC-2012-AdG 320539-duplex) for funding.
European Research Council (320539)
External DOI: https://doi.org/10.1021/jacs.7b06619
This record's URL: https://www.repository.cam.ac.uk/handle/1810/267878
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