STRUCTURE AND SELECTIVITY OF A SMALL DIMERIC ENCAPSULATING ASSEMBLY

The binding selectivity of a dimeric molecular capsule in solution and its X-ray crystal structure in the solid state are reported. The caps ule is a self-complementary bisglycoluril molecule, formed through a s eries of intermolecular hydrogen bonds, The dimeric host is capable of discriminating in CDCl3 solution between methane and ethane as guests , and direct evidence for the selectivity is presented from H-1 NMR st udies, The thermodynamic parameters for the encapsulation of methane, obtained from a VT H-1 NMR (500 mHz) study, are presented.