Theoretical study of inclusion complex between R/S-1-[1-(5-chloro-2-methoxyphenyl)ethyl]-3-methyl-3-phenylsulfonylurea and β-cyclodextrin

The inclusion process between β-cyclodextrin (β-CD) and R/S-1[1-(5-chloro-2-methoxyphenyl)ethyl]-3-methyl-3-phenylsulfonylurea (B16) has been investigated by using different methods of molecular modeling such as PM6 and ONIOM hybrid methods, to determine the most important interaction taking place in the inclusion complexation, deformation of molecules, HOMO and LUMO energies. In this study we took into account only the stoichiometry 1:1, two models of inclusion complex were built: A and B orientations. According to the results obtained from PM6 and ONIOM2 methods in a vacuum, the inclusion complex in B orientation is more favorable than A orientation. Once the most favorable inclusion complex is determined, a study of the different interactions between host and guest molecules is carried out by calculating the HOMO-LUMO gap. Theoretical studies propose that hydrophobic interaction and hydrogen bonding significantly determine the complexes stability.