Thermal effect of inclusion process of β-cyclodextrin (β-CD) with 6-benzyloxypurine (6-BOP) and 6-Benzylaminopurine (6-BAP) in aqueous solution at pH 8.9 has been determined with microcalorimetry at the temperature 298.15K. Standard enthalpy changes, stoichiometry, and equilibrium constants of the inclusion complexation have been derived based on the directly calorimetric data utilizing non-linear simulation. The thermodynamic parameters were discussed in the light of different structure of the guest molecules combining with UV spectra message of the host –guest interaction. The result indicates that β-CD possesses obvious function of molecular recognition to 6-Benzyloxypurine and 6-Benzylaminopurine.

Key words: 6-Benzyloxypurine, 6-Benzylaminopurine, β-Cyclodextrin, Molecular recognition, Microcalo-rimetry