Interpreting the nature of interactions in the inclusion complex of danofloxacin, a third-generation fluoroquinolone with Cucurbit[7]uril: A computational study

Abstract

The Stabilities and electronic structures of inclusion complexes formed between Cucurbit(7)uril and the third generation fluoroquinolone drug, danofloxacin and its zwitterionic form were investigated using the Density Functional Theory. The main aim of this study is to understand the nature of interactions existing between the host–guest molecules in these complexes. The binding and deformation energies, thermodynamic parameters and chemical reactivities of the complexes were calculated. The results indicate that complexation of the zwitterionic form of the drug molecule with CB7 is energetically most favourable. The process of creating these supramolecular complexes is thermodynamically spontaneous and exothermic. The MESP, NCI-RDG, and NBO analysis reveals that the electrostatic interactions and charge transfer between the host and guest molecules contributes to the stability of the complexes. These results are also supported by the Local Energy Decomposition Analysis performed for the complexes.