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Imani Z, Mundlapati VR, Goldsztejn G, Brenner V, Gloaguen E, Guillot R, Baltaze JP, Le Barbu-Debus K, Robin S, Zehnacker A, Mons M, Aitken DJ. Conformation control through concurrent N-H⋯S and N-H⋯O[double bond, length as m-dash]C hydrogen bonding and hyperconjugation effects. Chem Sci 2020; 11:9191-9197. [PMID: 34123167 PMCID: PMC8163419 DOI: 10.1039/d0sc03339a] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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 (C6γ), 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-C6γ feature that stabilizes a planar geometry in the monomer unit. Two contiguous C5-C6γ features in the planar dimer implicate an unprecedented three-centre H-bond of the type C[double bond, length as m-dash]O⋯H(N)⋯SR2, while the trimer adopts two C5-C6γ features separated by a Ramachandran α-type backbone configuration. These low-energy conformers are fully characterized in the gas phase and support is presented for their existence in solution state.
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Affiliation(s)
- Zeynab Imani
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay 91405 Orsay France
| | - Venkateswara Rao Mundlapati
- Laboratoire Interactions, Dynamiques et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay 91191 Gif-sur-Yvette France
| | - Gildas Goldsztejn
- Laboratoire Interactions, Dynamiques et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay 91191 Gif-sur-Yvette France
| | - Valérie Brenner
- Laboratoire Interactions, Dynamiques et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay 91191 Gif-sur-Yvette France
| | - Eric Gloaguen
- Laboratoire Interactions, Dynamiques et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay 91191 Gif-sur-Yvette France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay 91405 Orsay France
| | - Jean-Pierre Baltaze
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay 91405 Orsay France
| | - Katia Le Barbu-Debus
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay 91405 Orsay France
| | - Sylvie Robin
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay 91405 Orsay France .,Faculté de Pharmacie, Université de Paris 75006 Paris France
| | - Anne Zehnacker
- Institut des Sciences Moléculaires d'Orsay (ISMO), CNRS, Université Paris-Saclay 91405 Orsay France
| | - Michel Mons
- Laboratoire Interactions, Dynamiques et Lasers (LIDYL), CEA, CNRS, Université Paris-Saclay 91191 Gif-sur-Yvette France
| | - David J Aitken
- Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), CNRS, Université Paris-Saclay 91405 Orsay France
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