Separation Behavior of Common Fullerenes in Cyclodextrin-HPLC Based on Computationally-Derived Interaction Energies

Abstract

Molecular modeling and basic thermodynamic considerations are used to explain previously reported HPLC retention behavior of C₆₀ and C₇₀ using a σ-cyclodextrin stationary phase. Evidence thatinclusion complex formation between the fullerene and σ-cyclodextrin is not essential to resolve C₆₀ and C₇₀ is presented. Computationally-derived interaction energies alone do not correlate with the observed HPLC retention behavior. However, interaction energy values combined with mobile phase solubility data, non-inclusion interactions, and a discussion of entropy changes due to phase transfer provide a more thorough explanation of retention in this separation system.