Computational investigation of dimethoate and β-Cyclodextrin inclusion complex: molecular structures, intermolecular interactions and electronic analysis

Abstract

Abstract The proposed study concerns the inclusion complexation of dimethoate (DMT) in the β-cyclodextrin (β-CD) molecule cage using a 1:1 stoichiometry. The interactions between DMT and -CD were evaluated using PM7 and DFT in water and gas with base 6-31G(d,p); using the CAMB3LYP functional. All approaches agree with the optimal 3D structure, which includes full DMT inclusion in the CD cavity. Complexation, LUMO, and HOMO energies were computed. The natural bond orbital (NBO) and UV- visible calculations were determined and discussed. Additionally, the non-covalent intermolecular interactions between dimethoate and β-cyclodextrin are investigated through: reduced density gradient (RDG), non-covalent interaction (NCI) and independent gradient model (IGM) that the main forces stabilizing the examined inclusion complex are H-bond and Van Der Waals interactions. Furthermore, the energy decomposition analysis (EDA) emphasizes the importance of the H-bond as attractive interactions.