Host-guest complexes between cucurbit[n]urils and acetanilides having aminopropyl units

J Colloid Interface Sci. 2013 Jun 1;399:54-61. doi: 10.1016/j.jcis.2013.02.027. Epub 2013 Mar 4.

Abstract

2-(Propylamino)acetamide of aniline (1a), and bis-2-(propylamino)acetamide of ortho- (1b) and para-(1c) phenylenediamine form host-guest complexes with CB[6], CB[7] and CB[8] as evidenced by the variations in the (1)H NMR spectroscopy chemical shifts and observation in MALDI-TOF-MS and ESI-MS of ions at the corresponding mass. Binding constants for the 1:1 complexes were estimated from fluorescence titrations and were in the range 10(5)-10(6)M(-1). Models based on molecular mechanics for these supramolecular complexes are provided. In spite of the different geometries arising from the ortho- or para-substitution, phenylenediamides form complexes of similar strength in which the hydrophobic alkyl chains are accommodated inside the host cavity. Formation of these host-guest complexes in the solid state was also achieved by modifying an aminopropyl silica with chloroacetanilides and preparing three silica having analogues of compounds 1a-c anchored to the solid particles. Titrations showed, however, that these solids can adsorb a large percentage of CBs by unselective interactions that are not related to the formation of inclusion complexes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetanilides / chemistry*
  • Aniline Compounds / chemistry*
  • Bridged-Ring Compounds / chemistry*
  • Ions
  • Models, Molecular*
  • Phenylenediamines / chemistry*
  • Silicon Dioxide / chemistry*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization

Substances

  • Acetanilides
  • Aniline Compounds
  • Bridged-Ring Compounds
  • Ions
  • Phenylenediamines
  • Silicon Dioxide
  • aniline