Theoretical Evaluation of the Molecular Inclusion Process between Chlordecone and Cyclodextrins: A New Method for Mitigating the Basis Set Superposition Error in the Case of an Implicit Solvation Model

The aim of this work is to describe the molecular inclusion of chlordecone with α, β, and γ-cyclodextrin in aqueous solution using quantum mechanics. The guest-host complexes of chlordecone and cyclodextrins are modeled in aqueous solution using the Multiple Minima Hypersurfaces methodology with PM6-D3H4X semiempirical Hamiltonian, the lowest energy minima obtained are re-optimized using the M06-2X density functional and the intermolecular interactions described using Quantum Theory of Atoms In Molecules (QTAIM). The studied complexes are classified according to the degree of inclusion namely: total occlusion, partial occlusion, and external interaction. The more stable complexes are obtained when γ-CD is used as the host molecule. The interactions characterized through QTAIM analysis are all of electrostatic nature, predominantly of dispersive type. In this work, a method based on the counterpoise correction is also discussed, to mitigate the basis set superposition error in density functional theory calculations when using an implicit solvation model.