Anion receptors based on halogen bonding with halo-1,2,3-triazoliums

J Org Chem. 2015 Mar 20;80(6):3139-50. doi: 10.1021/acs.joc.5b00028. Epub 2015 Mar 3.

Abstract

A systematic series of anion receptors based on bidentate halogen bonding by halo-triazoles and -triazoliums is presented. The influence of the halogen bond donor atom, the electron-withdrawing group, and the linker group that bridges the two donor moieties is investigated. Additionally, a comparison with hydrogen bond-based analogues is provided. A new, efficient synthetic approach to introduce different halogens into the heterocycles is established using silver(I)-triazolylidenes, which are converted to the corresponding halo-1,2,3-triazoliums with different halogens. Comprehensive nuclear magnetic resonance binding studies supported by isothermal titration calorimetry studies were performed with different halides and oxo-anions to evaluate the influence of key parameters of the halogen bond donor, namely, polarization of the halogen and the bond angle to the anion. The results show a larger anion affinity in the case of more charge-dense halides as well as a general preference of the receptors to bind oxo-anions, in particular sulfate, over halides.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anions / chemistry
  • Binding Sites
  • Halogens / chemistry*
  • Molecular Structure
  • Quantum Theory
  • Triazoles / chemistry*

Substances

  • Anions
  • Halogens
  • Triazoles