BOWL-SHAPED MOLECULES AS ENZYME MODELS

Resorcinol-aldehyde tetramers (1a-c) possessing bowl shaped structures with hydrophobic cavity, prepared under acidic conditions, have been studied by H-1 NMR spectral studies are shown-to form host-guest complexes with a variety of guests like pyndinium methiodides. These cyclophanes help in solubilizing different hydrocarbons in the aq. phase. Although the discrimination favours benzene due to its complementarity to the cavity, the association constant is higher valued for acetophenone showing that hydrogen-bonding plays an important role in host-guest complex formation. The host-guest complexation is further utilized to catalyze or inhibit the hydrolysis of N-methyl-p-nitrophenylnicotinium isodide and amminolysis of tetramer 1b as compared to resorcinol diacetate with different amines.