Macromolecular recognition by cyclodextrins. Interaction of cyclodextrins with poly(N-acryloyl-amino acids)

The interactions of cyclodextrins (CDs) with poly(N-acryloyl-amino acids) (pAXaa) were investigated by 1H NMR and two dimensional nuclear Overhauser effect spectroscopy (2D NOESY) to elucidate the effect of attachment of amino acid residues to the polymer chain. Using the 1H NMR data measured at varying pAXaa concentrations, apparent association constants (K) were roughly estimated for the CDs/pAXaa systems. These apparent K values indicated that α-CD interacted with poly(N-acryloylphenylalanine) and with poly(N-acryloyltyrosine) and β-CD and γ-CD interacted with poly(N-acryloyltryptophan). Comparison of these apparent K values with those for the model compounds, i.e., amino acid sodium salts, revealed that the effect of attachment of amino acid residues to the polymer chain was stronger for a smaller amino acid residue.