High-Resolution Nuclear Magnetic Resonance Study of 6-O-α- d -Glucopyranosyl-α-cyclodextrin-p-Nitrophenol Inclusion Complex in Aqueous Solution

Abstract 6-O-α-d-Glucopyranosyl-α-cyclodextrin (G1-α-CD)-p-nitrophenol (pNP) inclusion complex has been characterized by high resolution 1H and 13C NMR. From 1H NMR measurements it is concluded that G1-α-CD forms a 1 : 1 inclusion complex with pNP at both pD 7 and 10, and the dissociation constants for their complexation are quite similar to those for α-CD–pNP complexation, suggesting that G1-α-CD and α-CD have a similar ability of complexation with pNP. The geometry of G1-α-CD–pNP complex was found to be similar to that of α-CD–pNP complex. Analysis on the NMR spectral parameters of G1-α-CD have revealed that the asymmetric nature of G1-α-CD molecule is enhanced by complexation with pNP.