A1 Journal article (refereed)
Oligoamide Foldamers as Helical Chloride Receptors : the Influence of Electron-Withdrawing Substituents on Anion-Binding Interactions (2019)

Helttunen, K., Annala, R., Suhonen, A., Iloniemi, J., Kalenius, E., Aragay, G., Ballester, P., Tuononen, H., & Nissinen, M. (2019). Oligoamide Foldamers as Helical Chloride Receptors : the Influence of Electron-Withdrawing Substituents on Anion-Binding Interactions. Chemistry : An Asian Journal, 14(5), 647-654. https://doi.org/10.1002/asia.201801869

JYU authors or editors

Annala, Riia
Suhonen, Aku
Tuononen, Heikki
Nissinen, Maija
Kalenius, Elina
Helttunen, Kaisa

Publication details

All authors or editors: Helttunen, Kaisa; Annala, Riia; Suhonen, Aku; Iloniemi, Juho; Kalenius, Elina; Aragay, Gemma; Ballester, Pablo; Tuononen, Heikki; Nissinen, Maija

Journal or series: Chemistry : An Asian Journal

ISSN: 1861-4728

eISSN: 1861-471X

Publication year: 2019

Volume: 14

Issue number: 5

Pages range: 647-654

Publisher: Wiley - VCH Verlag GmbH & Co. KGaA

Publication country: Germany

Publication language: English

DOI: https://doi.org/10.1002/asia.201801869

Publication open access: Not open

Publication channel open access:

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/63409

Abstract

The anion‐binding properties of three closely related oligoamide foldamers were studied using NMR spectroscopy, isothermal titration calorimetry and mass spectrometry, as well as DFT calculations. The 1H NMR spectra of the foldamers in [D6]acetone solution revealed partial preorganization by intramolecular hydrogen bonding, which creates a suitable cavity for anion binding. The limited size of the cavity, however, enabled efficient binding by the inner amide protons only for the chloride anion resulting in the formation of a thermodynamically stable 1:1 complex. All 1:1 chloride complexes displayed a significant favourable contribution of the entropy term. Most likely, this is due to the release of ordered solvent molecules solvating the free foldamer and the anion to the bulk solution upon complex formation. The introduction of electron‐withdrawing substituents in foldamers 2 and 3 had only a slight effect on the thermodynamic constants for chloride binding compared to the parent receptor. Remarkably, the binding of chloride to foldamer 3 not only produced the expected 1:1 complex but also open aggregates with 1:2 (host:anion) stoichiometry.

Keywords: supramolecular chemistry; anions

Free keywords: receptors; host-guest systems; foldamers

Fields of science: