Conformation control through concurrent N-H⋯S and N-H⋯O[double bond, length as m-dash]C hydrogen bonding and hyperconjugation effects.

ABSTRACT: In addition to the classical N-H⋯O[double bond, length as m-dash]C non-covalent interaction, less conventional types of hydrogen bonding, such as N-H⋯S, may play a key role in determining the molecular structure. In this work, using theoretical calculations in combination with spectroscopic analysis in both gas phase and solution phase, we demonstrate that both these H-bonding modes exist simultaneously in low-energy conformers of capped derivatives of Attc, a thietane α-amino acid. 6-Membered ring inter-residue N-H⋯S interactions (C6^γ), assisted by hyperconjugation between the thietane ring and the backbone, combine with 5-membered ring intra-residue backbone N-H⋯O[double bond, length as m-dash]C interactions (C5) to provide a C5-C6^γ feature that stabilizes a planar

SUBMITTER: Imani Z 

PROVIDER: S-EPMC8163419 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature