Quantum Mechanical Study of Complexation of Dopamine and Epinephrine with β-Cyclodextrin Using PM6, ONIOM and NBO Analysis

The structural aspects for complexation of dopamine (DA) and epinephrine (EP) to beta-CD were explored by using PM6, HF and ONIOM methods. The most stable structure was obtained at the optimum position and angle. The complex orientation in which the catechol ring of the guest penetrates into beta-CD cavity near primary hydroxyls is preferred in energy. The inclusion complex of DA with beta-CD is more stable than that of EP. The structures show the presence of several intermolecular hydrogen bond interactions that were studied on the basis of NBO analysis employed to quantify the donor-acceptor interactions between the guest molecules and beta-CD.