Experimental thermodynamics and molecular mechanics calculations of inclusion complexes of 9-methyl anthracenoate and 1-methyl pyrenoate with β-cyclodextrin

Steady-state fluorescence and molecular mechanics calculations were used to study the inclusion complexes of 9-methyl anthracenoate (MA) and 1-methyl pyrenoate (MP) with beta-cyclodextrin (beta CD). Binding constants of 1:1 complexes at different temperatures were obtained from the analysis of the fluorescence enhancement of the beta CD solutions with respect to the MA or MP free chromophores. The thermodynamic parameters Delta H and Delta S were also obtained. Molecular mechanics calculations were applied to study both inclusion processes in vacuo and in the presence of water as a solvent. Complexation is mainly due to nonbonded van der Waals host-beta CD interactions. Both MA and MP penetrate only partially into the beta CD cavity.