Dual Binding Modes of a Small Cavitand

ABSTRACT The small size and high cohesiveness of water means that water-mediated interactions are strongly context dependent.As a result, there is still much to learn about how non-polar solutes and ions interact with themselves or each other.To help address this issue, we report here on a cavitand host, TMAX-Cl (2). Possessing two different binding sites, a shallow non-polar dish that binds hydrophobes, and a crown of ammoniums that bind anions, TMAX-Cl (2) provides insight into the hydrophobic and Hofmeister effects.We find that binding to the non-polar site is weak, suggesting that a larger surface area is needed for substantial binding.In contrast, binding to the crown of ammoniums is relatively strong, despite the high dielectric of water.These findings provide a better understanding of water-mediated interactions, and define the supramolecular properties of TMAX-Cl 2 as we continue our studies of this host and related water-soluble cavitands. Graphical Abstract