Thermodynamics of binding of α-cyclodextrin to straight-chain alkyl derivatives in aqueous solution

Apparent standard Gibbs energy, enthalpy, entropy, and heat capacity data of the interactions of alpha-cyclodextrin (alphaCD) to some n-carboxylates H(CH2)(n)COO- (n = 4 - 6), are determined by isothermal titration microcalorimetry at different temperatures in phosphate buffer, pH 9.0, assuming a 1 : 1 model in dilute solution. Modelling of contributions of the thermodynamic properties of the solution indicates that aCD undergoes conformational change upon binding to homologous series of n-carboxylates, n-alcohols, alpha,omega-alkane dicarboxylates and alpha,omega-alkane diols.