Biomimetic macrocyclic receptors for carboxylate anion recognition based on C-linked peptidocalix[4]arenes

Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):4842-7. doi: 10.1073/pnas.062625499.

Abstract

Two neutral macrobicyclic anion receptors 4 and 6, containing a calix[4]arene in the cone conformation, two l-alanine units, and a 2,6-diacylpyridine or a phthaloyl bridge, are described. The x-ray crystal structure of the acetone complexes of the pyridine containing macrocycle 6 shows the four amide NH groups to be in close proximity to the chiral pocket delimited by the pyridine and one aromatic nucleus of the calix[4]arene. This conformation is also the most stable in acetone-d6 solution, as proven by one- and two-dimensional NMR spectral measurements. Electrospray ionization-MS and (1)H NMR experiments reveal that the two ligands strongly bind carboxylate anions in acetone solution. H-bonding interactions between the carboxylate anions and the amide NH groups, together with pi/pi stacking, are invoked to explain the efficiency and the selectivity of these anion receptors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anions
  • Calixarenes
  • Carbon / chemistry*
  • Crystallography, X-Ray
  • Hydrogen Bonding
  • Hydrogen-Ion Concentration
  • Ligands
  • Macromolecular Substances*
  • Magnetic Resonance Spectroscopy / methods*
  • Models, Chemical
  • Models, Molecular
  • Peptides / chemistry
  • Phenol / chemistry
  • Protein Conformation

Substances

  • Anions
  • Ligands
  • Macromolecular Substances
  • Peptides
  • Calixarenes
  • Phenol
  • Carbon