Computational study of inclusion complex formation between carvacrol and β-cyclodextrin in vacuum and in water: Charge transfer, electronic transitions and NBO analysis

The interactions between carvacrol (CAR) and β-cyclodextrin (β-CD) have been analyzed employing PM3, ONIOM2 and DFT methods in vacuum and in water. Complexation, deformation, HOMO and LUMO energies were determined and discussed. Van der Waals interactions are mostly responsible for enthalpy driven complex formation of CAR with β-CD. Finally, TD-DFT of visible spectra and NBO calculations were analyzed and discussed. Theoretical studies propose that hydrophobic interaction and hydrogen bonding play significant role in determining the stability of the complexes.