Complexation of small neutral organic molecules by water soluble calix[4]arenes

The inclusion of small neutral organic guests (alcohols, ketones and nitril es) by water-soluble calix[4]arene receptors was studied by H-1 NMR spectro scopy at neutral pH. The guests are included into the host hydrophobic cavi ty by their apolar aliphatic residues. The binding constants, determined by H-1 NMR titrations, confirm the importance of charge assistance in the apo lar binding of guests inside calixarene cavities and highlight the role pla yed by the conformational properties of the receptors in the recognition pr ocess. (C) 2000 Elsevier Science Ltd. All rights reserved.