Hetero Co-Encapsulation within a Supramolecular Cage. Moving Away from the Statistical Distribution of Different Guests.

Beside sensing and delivery, another peculiar property arising from confinement in discrete molecular hosts comes from the possibility to have in close proximity, and in defined position, two different molecules (hetero co-encapsulation). This phenomenon can be tuned considering steric and electronic properties of the guests. In this work, a study on the parameters affecting homo and hetero co-encapsulation processes within a supramolecular cage is reported. In particular, different benzoate guests were bound within a supramolecular cage containing two metal binding sites and the experimental binding thermodynamics measured. Unexpectedly, from competition experiments we observed that the maximum concentration of hetero co-encapsulation is achieved if a weakly binding guest is used to partially displace a strongly binding guest.