A Highly Efficient Neutral Anion Receptor in Polar Environments by Synergy of Anion-π Interactions and Hydrogen Bonding

J Chem Inf Model. 2021 Sep 27;61(9):4455-4461. doi: 10.1021/acs.jcim.1c00595. Epub 2021 Aug 16.

Abstract

Herein, it is shown how anion recognition in highly polar solvents by neutral metal-free receptors is feasible when multiple hydrogen bonding and anion-π interactions are suitably combined. A neutral aromatic molecular tweezer functionalized with azo groups is shown to merge these two kinds of interactions in a unique system and its efficiency as an anion catcher in water is evaluated using first-principles quantum methods. Theoretical calculations unequivocally prove the high thermodynamic stability in water of a model anion, bromide, captured within the tweezer's cavity. Thus, static calculations indicate anion-tweezer interaction energies within the range of covalent or ionic bonds and stability constants in water of more than 10 orders of magnitude. First-principles molecular dynamics calculations also corroborate the stability through the time of the anion-tweezer complex in water. It shows that the anion is always found within the tweezer's cavity due to the combination of the tweezer-anion interactions plus a hydrogen bond between the anion and a water molecule that is inside the tweezer's cavity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anions
  • Hydrogen Bonding
  • Solvents
  • Thermodynamics
  • Water*

Substances

  • Anions
  • Solvents
  • Water