Spectrophotometric study of the interaction of β-cyclodextrin with hydroxamic acids

Cyclodextrins have attracted considerable interest because of their ability to form stable inclusion complexes with a wide variety of inorganic and organic guest molecules. In the present communication, binding constant of beta-cyclodextrin and a series of substituted benzohydroxamic acids (X-C6H4CON(OH) H), X = H, 4-NO2, 4-Me 4-OMe, and 2-OH and N-phenylbenzohydroxamic acid (C6H5CON(OH)C6H5) were determined at 27 degrees C spectrophotometrically. In all the cases the formation of 1: 1 host-guest complex was established. The addition of beta-CD results in an increase in the absorbance intensity but does not cause a shift in lambda(max). The values of binding constants are in good agreement with in those determined from kinetic and pH metric techniques.