Selective encapsulation and sequential release of guests within a self-sorting mixture of three tetrahedral cages.

A mixture of two triamines, one diamine, 2-formylpyridine and a Zn(II) salt was found to self-sort, cleanly producing a mixture of three different tetrahedral cages. Each cage bound one of three guests selectively. These guests could be released in a specific sequence following the addition of 4-methoxyaniline, which reacted with the cages, opening each in turn and releasing its guest. The system here described thus behaved in an organized way in three distinct contexts: cage formation, guest encapsulation, and guest release. Such behavior could be used in the context of a more complex system, where released guests serve as signals to other chemical actors.