Molecular mechanisms of β-cyclodextrin solubilization in natural deep eutectic solvents: A quantum chemical investigation

Abstract

Cyclodextrins, particularly β-cyclodextrin (β-CD), exhibit remarkable host-guest complexation capabilities due to their unique toroidal structures. Natural deep eutectic solvents (NADES), biocompatible mixtures of readily available components, represent sustainable alternatives to conventional solvents with tunable physicochemical properties. This work investigates the molecular interplay between β-CD and NADES, focusing on their potential to create sustainable, multifunctional materials. Two configurations were explored: (i) β-CD dissolved in NADES and (ii) β-CD acting as a NADES component. Using density functional theory simulations, the study examined intermolecular forces, confinement effects, and molecular topology to characterize host–guest interactions between atomistic models of selected NADES (menthol + thymol and menthol + decanoic acid) and β-CD complexes. Energetic and kinetic analyses provided insights into the driving forces and timescales of complexation processes. The findings contribute to a mechanistic understanding of NADES–CD systems, enabling rational selection of solvent compositions and cyclodextrin forms for optimized guest encapsulation and targeted functionalities.