DFT prediction of Dichlorvos β-cyclodextrin inclusion complex: energetic and non-covalent interaction insights

This study investigates the host–guest inclusion complexes involving Dichlorvos and β-cyclodextrin (β-CD) using density functional theory with dispersion correction (DFT-D). The computations utilized the ωB97XD functional with the split valence double zeta 6-31G(d,p) basis set. Our primary objective was to examine the molecular structure, interactions, thermodynamic features, inclusion process, and stabilization energies of Dichlorvos and β-CD inclusion complexes in both gaseous and aqueous phases. Our results indicate that the B orientation, where the chlorine atoms of Dichlorvos enter the β-CD cavity from its narrow side, is more energetically favorable compared to the A orientation, where the chlorine atoms enter from the broad side. Specifically, the complexation energy for orientation B is − 49.59 kcal/mol in water, compared to − 24.15 kcal/mol for orientation A. The interaction energy for orientation B is − 32.20 kcal/mol in water, whereas for orientation A, it is − 24.15 kcal/mol. Additionally, we provided a comprehensive characterization of hydrogen bonding within these inclusion complexes using non-covalent interaction (NCI-RDG) and independent gradient model (IGM) methods. Our findings highlight that dispersion forces play a crucial role in stabilizing these complexes, with significant contributions from electrostatic interactions. Furthermore, the energy decomposition analysis (EDA) was employed to dissect and analyze the various bonding contributions in these complexes. The results underscore the critical importance of dispersion forces in stabilizing the complexes, while also highlighting the substantial influence of electrostatic interactions.