Acceleration of amide bond rotation by encapsulation in the hydrophobic interior of a water-soluble supramolecular assembly
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Updated: Jul 3, 2026

Synthesis of Information-bearing Peptoids and their Sequence-directed Dynamic Covalent Self-assembly
Published on: February 6, 2020
Michael D Pluth1, Robert G Bergman, Kenneth N Raymond
1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.
Abstract:
The hydrophobic interior cavity of a self-assembled supramolecular assembly exploits the hydrophobic effect for the encapsulation of tertiary amides. Variable-temperature (1)H NMR experiments reveal that the free energy barrier for rotation around the C-N amide bond is lowered by up to 3.6 kcal/mol upon encapsulation. The hydrophobic cavity of the assembly is able to stabilize the less polar transition state of the amide rotation process. Carbon-13 labeling studies showed that the (13)C NMR chemical shift of the carbonyl resonance increases with temperature for the encapsulated amides, which suggests that the assembly is able to favor a twisted form of the amide.
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