Free‐energy calculations of the host–guest association in grafted supramolecular assemblies

Abstract

Herein, we investigate the impact of grafting macrocyclic hosts with hydrophobic cavities onto a gold surface on the association with a guest molecule of particular importance to applications for molecular machines. We establish that the increase of the grafted alkyl chain length and number of anchor points strengthens the binding of the guest with the β‐cyclodextrin host. This is the opposite effect with the p‐sulfonatocalix[4]arene host for which the grafting considerably reduces the strength of the host–guest association. The structural and thermodynamic characterizations, carried out with free energy simulations, are combined to rationalize the differences in the association process in both heterogeneous and homogeneous conditions.