Reversible Encapsulation of Disc-Shaped Guests by a Synthetic, Self-Assembled Host

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Science  26 Jan 1996:
Vol. 271, Issue 5248, pp. 487-489
DOI: 10.1126/science.271.5248.487


Here, the synthesis of a bowl-shaped molecule is described and evidence of its reversible dimerization by means of hydrogen bonds is presented. The dimer features a flattened spherical cavity of peculiar symmetry and acts as a host for the encapsulation of guest molecules of complementary shape. Encapsulation of aromatic guests in chloroform solution and of cyclohexane in p-xylene solution was demonstrated by nuclear magnetic resonance experiments. The passage of guests into and out of the cavity is slow and occurs on a time scale of hours. The system was used to explore the effects of size, shape, and solvation on molecular recognition coupled with assembly.