Molecular recognition and assembly.

The synthesis and characterization of a series of self-assembling capsules is described. Assembly takes place as a result of the self-complementary hydrogen bonding patterns on the subunit pieces and dimerization occurs in such a manner that the concave surfaces of the two subunits are directed at one another. This feature gives rise to close-shelled capsules which are shown to encapsulate smaller guest species. Selectivity is shown for guests ranging in size from methane to adamantane derivatives. Shape selectivity is shown in special capsules capable of recognizing disc-like molecules such as benzene and cyclohexane. Disproportionation reactions are shown to exist between capsules of slightly different sizes, and these are shown to be controlled by the nature of the guest species. The use of these capsules as reaction chambers is proposed.