Hydration and Counterion Binding of an Aminomethylated Resorcin[4]arene.

Supramolecular chemistry based on host-guest complexes is a rapidly evolving research field with numerous potential applications. However, up to date investigations mainly focused on molecular recognition and self-assembly in nonpolar media where hydrogen-bond formation could be used for selective host-guest binding. Obviously, in aqueous solutions hydration will compete, hampering supramolecular chemistry to go green. As practically no information on host hydration is available yet, we study in this contribution the competition of hydration and counterion binding for the aminomethylated resorcin[4]arene hydrochloride, TAM·(HCl)4, using dielectric spectroscopy. We find that TAM·(HCl)4 is strongly hydrated but binds Cl- ions only weakly in a noncooperative manner.