Heptakis(2,3-di-O-carboxymethyl)-(beta)-cyclodextrin as a pH-sensitive Host

Acid-dissociation of heptakis(2,3-di-O-carboxymethyl)-(beta)-cyclodextrin occurred between pD 2 and 6. At pD 2.0, 1pyrenesulfonate was included into the host cavity with a binding constant of 2300 (plus-minus) 100 M^-1, while no complexation occurred at pD > 6.0. Much sharper pH-dependency in complexation proceeded with 1-anilino-8naphthalenesulfonate and 2-(p-methylanilino)-6-naphthalenesulfonate.