Under the Influence of Water: Molecular Recognition of Organic Hydrophilic Molecules in Water with a Prismarene Host Driven by Hydration Effects

A water-soluble prism[5]arene host can form endo-cavity complexes with hydrophilic organic substances in water by displacing frustrated water molecules from its deep cavity. Water molecules structured at both rims of the prismarene host can mediate hydrogen bonding interactions with the guest. Water-mediated hydrogen bonding interactions were invoked here to elucidate the elevated binding affinities and selectivity of the prismarene host toward hydrophilic organic guests. We show that water at the interface of a host-guest complex can act as an extension of the host structure, facilitating the accommodation of neutral guests within the binding site. This study highlights the crucial role of water in facilitating supramolecular interactions between a deep-cavity prismarene host and organic hydrophilic guests in aqueous medium.