Computational study of the encapsulation of an organic polluant with beta-CD, in vacuum and in water

This article reports the results of a theoretical study of the host/guest inclusion complex involving a herbicide called Diuron in β-cyclodextrin. Various computational techniques were used to determine the structure, geometry and stability energies of the complex. The analysis of the diuron/β-CD inclusion complex was performed both in vacuum and in water in a 1:1 ratio. The DFT/B97-3C method was used to obtain the structures of the complexes and to calculate their stability energies. The specific configurations were determined using nuclear magnetic resonance spectroscopy. The interaction bonds were investigated and the formation of conventional hydrogen bonds was detected by AIM analysis. The nature of the interactions was further elucidated using the method of non-covalent interactions (NCI). This showed that hydrogen bonds and van der Waals interactions contribute significantly to the formation of the inclusion complex. To gain more insight into the absorption and emission energies of the investigated complex, the gap energy (EHOMO-ELUMO) was calculated.