LAUSR

In this research, the encapsulation and intermolecular non-bonded interactions of an anticancer drug, Diethylstilbestrol (DES), into the inner surfaces of BNNT (8,8–12) were investigated. All Density Functional Theory (DFT) calculations were performed in a gas phase. So, this research focuses on intermolecular hydrogen bonding, van der Waals and steric interactions between active sites of the BNNT and DES by quantum theory of atom in molecule (QTAIM) theory. QTAIM and non-covalent interaction index (NCI) analyses showed the interactions between the DES drug and the BNNT nanotube. The HOMO-LUMO orbitals, Density of States (DOS) plots, and reduced density gradient (RDG) analyses were carried out to determine the effect of DES adsorption into the nanotube. Furthermore, the effect of the abovementioned interactions between the DES and BNNT (8,8–12) on the electronic characteristics, and natural charges have also been estimated. Based on the results, the thermodynamic parameters of BNNT (8,8-12)/DES are in very close agreement with the NCI analysis and showed that the BNNT (8,8–12) adsorb DES via a physisorption process rather than chemical one and the sorption procedure was exothermic in benign and thermodynamically favorable. Therefore, the use of BNNT (8,8–12) as a carrier for DES drug has been confirmed theoretically.