In silico properties characterization of water-soluble γ-cyclodextrin bi-capped C60 complex: free energy and geometrical insights for stability and solubility.

Cyclodextrin-related host-guest encapsulation is pivotal to modulate the solubility of C60, thereby promoting its potential therapeutic applications. Here we present a computational study on γ-cyclodextrin bi-capped C60 complex, probing characteristics for all the possible stoichiometry in aqueous solution. The potential of mean force (PMF) delineating the association process was computed, while the geometrical features of corresponding thermodynamically-favored stoichiometry are captured by molecular dynamics simulations, which provides insightful explanations to previous experimental and computational results. PMF partitioning indicates that intermolecular van der Waals dispersion forces are essential for molecular recognition and self-assembly, and the hydrogen-bonding interactions play a key role in dissolving the complex in water.